C Viburnum - Viburnum spp. - Clemson University

CHAPTER 5

Viburnum - Viburnum spp.

William E. Klingeman, University of Tennessee © Sarah A White 2012
Sarah A. White, Clemson University
Anthony V. LeBude, North Carolina State University
Nicole Ward Gauthier, University of Kentucky
Frank Hale, University of Tennessee
Amy Fulcher, University of Tennessee

SECTION 1 The genus Viburnum contains deciduous, sometimes evergreen, shrubs or small trees with
tremendous ornamental merit for all seasons. There are approximately 150 species of
Introduction viburnum native to North and Central America, Europe, North Africa, and Asia (Rehder,
1927; Krüssmann 1984; Dirr, 2007). Those viburnum species native to North America and
© Sarah White, CU common in commerce include V. acerifolium, V. bracteatum, V. cassinoides, V. dentatum, V.
lantanoides, V. lentago, V. nudum, V. obovatum, V. opulus var. americana, V. prunifolium, V.
VIBURNUM BASICS rafinesquianum, and V. rufidulum. None of the U.S.-native viburnum species are evergreen
nor do they have a particularly pleasing fragrance. Native viburnums possess vibrant fall
1. Economic Value foliage (Figure 5.1A), produce large volumes of bright colored berries (Figure 5.1B), and
2. Species and Cultivar Characteristics have the capability of surviving in wetlands to dry uplands and in a variety of habitats
3. Adaptability and Nutritional Needs ranging across these two extremes. Evergreen foliage can be found in viburnum species
like V. tinus from Southern Europe, V. rhytidophyllum from central Asia, and V. awabuki
This chapter is adapted from a review article submitted for publication in The Journal of Environmental ‘Chindo,’ V. suspensum, and V. davidii from the Far East. With the exception of V.
Horticulture in 2014, entitled “A Review of Arthropod Pests, Plant Diseases and Abiotic Disorders and rhytidophyllum, plants with evergreen foliage are not usually as cold hardy as their
their Management on Viburnum Species in the Southeastern U.S.” by William E. Klingeman, Sarah A. deciduous counterparts, and may not be as fragrant as other viburnums native to the same
White, Anthony V. LeBude, Amy Fulcher, Nicole Ward Gauthier, and Frank Hale. area. Viburnum species have been hybridized to create cultivars with desirable foliage, fall
color, and fragrance, while other breeding strategies have produced stalwart evergreens for
the landscape (Table 5.1 - end of section 1).

Economic Value
About 30 species or hybrids comprise most viburnum sales in the southeastern U.S. (Plant
and Supply Locator, 2014; Table 5.2). Including these selections, some 4.67 million
evergreen and deciduous viburnum plants are produced by about 1,592 U.S. operations,
which, in turn reported wholesale revenues exceeding $40.9 M in 2007 (USDA, 2009).
Roughly 25 percent of the total wholesale revenue ($10.7M) is generated from Region 4,
containing the southeastern U. S., followed by Regions 2 ($6.7M, Northeast) and 5 ($5.2M,
upper Midwest, Table 5.3). Regionally, these farm gate sales shift in plant material types
from mostly evergreen in the south to a balance in the mid-Atlantic regions to more
deciduous in the upper Midwest. Presumably, this is due to cold hardiness of the two types
of viburnum and not to market preference. Demand for viburnum is so great that GIE

AB

© Winston Dunwell, UK
Figure 5.1 Vibrant fall color (A) of V. plicatum ‘Spellbound’ and brightly colored berries
(B) of V. dentatum

122

Table 5.2 Number of production nurseriesZ growing various Viburnum species reportedY ABC
for twelve southern states

Species Number of Nurseries

Viburnum odoratissimum and cultivars 122

V. suspensum 116

V. obovatum and cultivars 71 © Winston Dunwell, UK © Winston Dunwell, UK © Sarah White, CU

V. dentatum and cultivars 23 Figure 5.2 Viburnum foliage differs in texture, thickness, and coloration (A) V. tinus
davidii ‘Sapphire Sunset’, (B) V. rafinesquianum ‘Louise’s Sunbeam’, and (C) V.
V. plicatum var. tomentosum and cultivars 13 rhytidophyllum
V. xpragense 13

V. macrocephalum 10 Media polled 4,000 of its Lawn & Landscape Magazine readers in April 2011 regarding
their plant material purchases. Viburnum was number two on the list behind boxwood
V. tinus and cultivars 10 (Anonymous, 2011).

V. trilobum and cultivars 6

V. carlesii and cultivars 5

V. lentago 5 Species and Cultivar Characteristics
The desirable traits for viburnum range from fragrant flowers, lustrous dark green foliage,
V. nudum and cultivars 5 brilliant fall color, to extravagant fruits and branch architecture that can anchor a winter
landscape. Leaves are oppositely attached to stems and their margins can be entire, dentate
V. prunifolium 5 with small teeth, or lobed (Rehder, 1927). Foliage texture can be thick and smooth, rough
textured and glabrous, corrugated, thin, or slender with subtle venation. Leaf colors range
V. rhytidophyllum and cultivars 5 from dull green to metallic blue, and color combined with various textures creates foliar
attributes that enhance nearby garden plants when viburnum are not in flower (Figure 5.2).
Z Only Viburnum species in production at more than 5 nurseries were included. Cultivars were grouped Flowers are tubular, yet small and come in white or pinkish colors (Figure 5.3A, B). The
within each species when more multiple cultivars were available display of flowers in umbel-like or paniculate compound cymes, condenses many small
flowers into attractive inflorescences, thus creating a larger, slightly curving flat
Y (Plant Supply Locator, 2014) inflorescence or sometimes a truss or ball of flowers (Figure 5.3C-E). Flowers can be all
fertile, as in V. xjuddii, mostly sterile, as in V. macrocephalum, or have both flower types
Table 5.3 Wholesale revenue generated by region for deciduous or evergreen sales of
viburnum in the U.S.Z present in the inflorescence to varying degrees as in V. plicatum var. tomentosum. Sterile
flowers are showy, irregularly shaped florets extended on small pedicels displayed
RegionY States within regionX Deciduous Evergreen Total prominently on the margins of inflorescences when both flower types are present. Flowers
Value ($1,000) can have a wonderfully delicate, yet complex sweet-spicy fragrance, no perceptible
fragrance, or an unpleasant odor that can become worsened when flowers are wet or
1 CT, MA 708 19 727 decomposing.
2 NJ, PA, NY 3,876 2,837 6,713
3 MD, VA 1,460 1,633 The fruit is a one-seeded drupe with a hard stone that provides radiant color in the
4 FL, TN, NC, SC, KY, GA, AL 173 7,465 10,680 landscape and food for wildlife. Fruit colors can be dynamic changing from green to blue,
5 OH, IL, WI, MI, IN, MN 3,215 1,453 5,170 red, purple, orange, yellow or black, with combinations of these colors on the same. Fall to
6 TX, AR, LAW 3,717 winter fruit display of viburnums can combine clusters of bright red berries and scarlet-
9 CA 18 41 orange fall color along with grey or brown stems. In some circumstances, high seed
10 OR, WA, ID 23 1,293 3,789 viability among non-native viburnums has raised concerns of possible plant invasiveness.
Total United States 2,496 3,712 6,364 Viburnum dilatatum, for example, is an Asian species with several different commercially-
2,652 22,090 40,857 traded cultivars that has high seed viability and propensity for establishing dense,
18,767 competitive thickets (Dirr, 2007). These characteristics has led to placement of this, as

Z (USDA, 2009) 123
Y Standard federal regional boundaries
X States are arranged within region by descending total sales of viburnum
W Not all states reported revenue from this region

A well as other viburnum species (V. lantana, V. AB
plicatum, V. plicatum var. tomentosum, V. setigerum, V.
seiboldii), on at least one regional list of potentially © Matthew Chappell, UGA
invasive species (Anonymous, 2013). Microsatellite Figure 5.4 Viburnum PearlificTM (A) after 7 years in the landscape and (B) blooming habit
markers have been characterized for V. dilatatum that of V. PearlificTM (right) beside ‘Nantucket’ (left)
will be used to assist ongoing viburnum breeding
efforts that can lead to development of sterile cultivars produced in several commercially important cultivars (Table 5.1). ‘Mohawk’ viburnum
(Dean et al., 2011). reaches seven feet high and wide, and has three inch wide rounded cymes in early spring
consisting of dark red flower buds that open to pinkish flowers (Figure 5.3A, B). The
B In winter, some viburnum stems are dark brown to fragrance rivals any plant available in the trade. The rough textured, dark green foliage
maroon and covered with dormant buds and a brown obtains streaks of orange-red first, and then becomes scarlet-red in fall among sparsely
velvety pubescence. Though most plants are present red berries that turn black eventually before both berries and leaves fall in winter.
deciduous, their stocky branches, oppositely arranged, Plants are intermediate in height and branch density and hardy to USDA Plant Hardiness
create a screening mass that successfully hides Zones 4-7a.
unsightly views, utilities, or creates privacy. This
mass can be spreading wider than tall, rounded to oval Two exemplary deciduous viburnums, known less for fragrance and small stature, and
or simply upright and tall. The small statured more for bright white flowers, fall color, and splendid berry displays include V. dentatum
(Figure 5.1B) and V. Pearlific™ (Figure 5.4). Viburnum dentatum is native from southern
C evergreen plants make great foundation plants in Canada south to Georgia and thrives in almost every landscape imaginable within that
partial shade to full sun, or manicured hedges, sweetly range. A large growing shrub with dark green, coarse textured, serrated foliage with deep
scented, along southern streets. Diversity within the veins, this viburnum has slightly off-scented white flowers followed by brilliant blue
genus truly lends itself to almost any garden situation berries. Since it is extremely cold hardy to USDA Plant Hardiness Zone 4, some cultivars
in every season. For example, V. awabuki ‘Chindo,’ V. produced from seeds collected in more northerly ranges have trouble adapting to the south.
plicatum var. tomentosum ‘Mariesii,’ V. prunifolium, V. This provenance effect manifests itself as early leaf drop with minimal or no fall color
rhytidophyllum, V. xrhytidophylloides, V. tinus, and V. when planted in the south. Choose cultivars that are adapted to heat for the south unless
trilobum are valuable large shrubs for use under utility ultimate sales are destined for colder climates (Table 5.1).

D lines to decrease the need for trimming (Touchette and The other deciduous viburnum is new from Plant Introductions, Inc., bred by Dr. Michael
Appleton, 1995). Dirr and marketed through Bailey Nurseries. Viburnum Pearlific™ is a hybrid obtained by
parental crosses of V. macrocephalum form keteleeri with
 V. ‘Eskimo,’ which descends
Most of the commercially available cultivars and from V. utile, thus plants are evergreen and heat tolerant (Table 5.1). According to Dirr, the
species are described in Table 5.1. A few exemplary dark green coloration of PearlificTM foliage is maintained throughout winter. Flowers are
clones will be described here to provide a brief survey. white, slightly fragrant and have red to black fruits. PearlificTM is more compact, growing
The first is V. burkwoodii ‘Mohawk’ introduced by the 5 feet (1.5 meters) tall by 6 feet (1.8 meters) wide after 7 years in trials in Georgia. Dirr
U.S. National Arboretum in 1966 by Dr. Donald adds that PearlificTM has been more vigorous than V. ‘Conoy’ and produces abundant
E Egolf. ‘Mohawk’ is a cross between V. carlesii, thus flower buds on young container-grown plants (Dirr, M.A., personal communication, 17 Oct
providing spicy-sweet clove fragrance and cold 2013).
hardiness to USDA Plant Hardiness Zones 4-6. By
contrast, V. utile contributes evergreen, lustrous green 124
foliage and heat tolerance in southern landscapes.
Breeding efforts that included these two species (and
individual crosses to other parent species) have

Figure 5.3 Tubular flower buds of V. burkwoodii ‘Mohawk’ (A) and flowers of (B) V.
burkwoodii ‘Mohawk.’ (C) V. lobophyllum, (D) V. opulus, and (E) V. plicatum var.
tomentosum

Adaptability and Nutritional Needs
Viburnum species are tolerant of a range of solar exposures from full sun to part shade.
For example, V. ‘Pragense’
 tolerates full sun to up to 60% shade during production; plants
produced in both conditions were of similar size and overall quality. Plants grown in shade
had a higher number of leaves per plant (Fini et al., 2010).

Most of the nitrogen (N) absorbed by V. odoratissimum is taken up when shoots are
actively growing, rather than when roots are actively growing. Viburnum odoratissimum
shoot and root growth is cyclical, yet can be affected by N. Normally, peak root growth
occurs 6 to 18 days before shoot growth begins (Schoene and Yeager, 2006). Nitrogen
fertilization rates of 100 ppm N resulted in three root growth flushes, while plants fertilized
with 50 ppm N or less had four root growth flushes. The majority of N (70%) absorbed
while roots are actively growing is, in turn, translocated into mature leaves; when shoots
are actively elongating, the majority of N fixed in expanding tissues is likely to be
mobilized from mature tissues (Schoene and Yeager, 2007).

Many species of Viburnum can adapt to a range of soil moisture levels (García-Navarro et © Wise Nurseries, LLC

al., 2004). As a consequence, viburnum plants should be irrigated according to daily water Figure 5.6 Viburnum odoratissimum (Awabuki Sweet Viburnum) in
production at Wise nurseries.
use (DWU), which represents the daily volume of water lost to evapotranspiration from
efficiently, with no decrease in plant quality (Figure 5.5; García-Navarro et al., 2004).
plants plus that lost via evaporation from the growing substrate. This approach has been
By contrast, Sweet viburnum (V. odoratissimum) are high water use plants, and plant
examined as a means of enhancing crop growth while reducing water applications to quality will decline if plants are allowed to dry down excessively (>20% plant available
moisture used) between irrigation events (Figure 5.6; Beeson, 1995). As long as plants
commercial nursery systems. Plants of V. receive the appropriate volume of irrigation, whether in a single application or via cyclic
irrigation, plant growth will not be affected (Beeson, 1998). Million and colleagues
dentatum ‘Ralph Senior’ produced in trade 3- (2007a) determined that 0.4 in (1 cm) per day of applied overhead irrigation was adequate
for commercial production of V. odoratissimum. When 0.8 in (2 cm) per day was applied,
gallon (11.4 L) containers were irrigated to 95% of the water was collected as runoff. Plants grown under a higher irrigation regime
were smaller, regardless of controlled release fertilizer (CRF) application rate. The
achieve either 100% DWU (100 DWU), 100 excessive irrigation rates led to nutrient leaching from containers, which reduced the
amount of nutrient available for plant growth (Million et al., 2007a).
DWU alternated every other irrigation cycle
When evapotranspiration-based irrigation scheduling was used for container grown V.
with 75% DWU (75DWU), or a three-cycle odoratissimum, water application volumes were reduced by 39% and water lost to leaching
by 42% (Million et al., 2010). By reducing leaching, 16% of N, 25% of P and 22% of K
schedule of 100 DWU, 75 DWU, and remained within the container, accessible to the crop, compared with V. odoratissimum
plants that were irrigated with the standard 1cm per day application rate. The maximum
75DWU. Warsaw and colleagues (2009) evapotranspiration rate of market-ready V. odoratissimum grown in trade 3-gallon (11.4 L)
containers was 0.3 gal (1.14 L) per day (Beeson, 2010).
reduced irrigation volumes by 33%, 41%, and


44% respectively, when treatments were
125
compared to a control irrigation standard of

1.9 cm (0.75 in) water per application. At the

end of two subsequent growing seasons, V.

dentatum ‘Ralph Senior’ plants grown with

water deficit treatments were larger than

control plants. After two seasons of growth,

EC measurements indicated that salinity levels

had not increased enough to affect plant

quality (Warsaw et al., 2009). Similarly, the

leaf area of V. tinus grown with deficit

irrigation was larger than V. tinus irrigated © Sarah White, CU

daily to container capacity, and deficit Figure 5.5 Viburnum tinus for sale at a
irrigated plants used the water applied more retail garden center

Table 5.4 Average range of foliar concentrations reportedZ for macronutrient (A) and micronutrients (B) measured in recently mature leaves collected at mid-season from current season’s
growth of select Viburnum species

(A) Macronutrient Nitrogen Phosphorus Potassium Calcium Magnesium Sulfur
(N) (P) (K) (Ca) (Mg) (S)
Viburnum awabuki
Viburnum burkwoodii 1.54 0.63 % dry weight 0.22 0.34
Viburnum bodnantense 1.21-2.32 0.16-0.22 0.22-0.29 0.13-0.20
Viburnum bracteatum 1.93 0.28 2.87 1.54 0.29 0.18
Viburnum carlesii 'Cayuga' 2.26 0.28 0.36 0.18
Viburnum cassinoides 1.52-2.32 0.20-0.73 1.16-1.41 1.41-2.84 0.40-0.43 0.15-0.21
Viburnum dentatum Y 1.88 0.15 0.29 0.15
Viburnum dilatatum 2.18 0.23-0.25 2.55 1.75 - -
Viburnum juddii 1.83-2.01 0.09-0.12 0.23-0.42 0.16-0.20
Viburnum macrocephalum 1.84 0.19 1.4 1.38 0.44 0.19
Viburnum obovatum 1.79-1.93 0.17-0.21 0.20-0.26 0.13-0.15
Viburnum odoratissimum 1.19 0.18 1.09-1.53 1.54-2.16 0.15 0.11
Viburnum opulus 'Roseum' 1.53 0.17 0.16 0.14
Viburnum plicatum Y 2.46-3.29 0.21-0.47 0.84 1.22 0.2 0.27
Viburnum xpragense 0.97-2.42 0.09-0.23 0.13-0.34 0.13-0.25
Viburnum rhytidophylloides 1.61-1.90 0.16-0.17 1.12-1.18 - 0.27-0.29 0.15-0.16
Viburnum rufidulum 1.79-2.06 0.16-0.54 0.21-0.36 0.15-0.17
Viburnum suspensum 1.2 0.14 1.18-1.48 1.91-2.88 0.25 0.12
Viburnum tinus Y 1.50-2.50 0.15-0.40 0.25-1.00 0.20-0.40
Viburnum x'Eskimo' 1.47-1.94 0.10-0.25 0.98 2.35 0.20-0.21 0.15
1.59-2.11 0.23-0.29 0.16-0.34 0.16-0.18
1.08-1.12 1.33-1.52

0.86 0.97

1.73 1.47

1.83-2.93 1.72

0.77-2.05 0.97-2.75

1.24-1.35 1.96-2.13

1.43-2.28 0.81-1.82

1.75 1.98

0.90-2.00 0.66-1.50

1.51-1.99 0.68-0.84

1.26-1.49 1.81-2.08

126

Table 5.4 continued Average range of foliar concentrations reportedZ for macronutrient (A) and micronutrients (B) measured in recently mature leaves collected at mid-season from current
season’s growth of select Viburnum species

(B) Micronutrient Iron Manganese Boron Copper Zinc Molybdenum Aluminum Sodium
(Fe) X (Mn) W (B) (Cu)W (Zn)W (Mo) (Al) (Na)

ppm (µg/g)

Viburnum awabuki 58 83 46 9 131 0.12 182 78
Viburnum burkwoodii 75-278 90-384 45-80 4-11 17-183 0.12-1.29 136-241 50-251
Viburnum bodnantense 49 97 53 2 61 0.02 99 88
Viburnum bracteatum 70 31 43 7 58 0.12 180 45
Viburnum carlesii 'Cayuga' 76-222 148-357 47-79 6-9 40-228 0.12-0.30 208-216 57-188
Viburnum cassinoides 55 406 48 4 24 0.12 115 83
Viburnum dilatatum 76-97 280-376 44-77 3-9 38-156 0.12-0.30 142-229 50-156
Viburnum juddii 115 336 64 8 31 0.12 340 49
Viburnum macrocephalum 71-104 113-384 76-114 6-8 24-27 .012-0.30 123-201 33-36
Viburnum obovatum 25 75 24 4 27 0.12 24 130
Viburnum odoratissimum 63 38 45 5 63 0.08 85 101
Viburnum opulus 'Roseum' 83 52 110 7 29 0.12 137 86
Viburnum plicatum Y 40-133 58-568 35-81 1-7 18-150 0.02-0.52 32-240 22-404
Viburnum xpragense 80-134 178-246 22-60 3-9 17-55 0.12-0.30 174-179 48-82
Viburnum rhytidophylloides 41-314 115-170 27-45 7-12 34-68 0.13-2.37 68-595 65-172
Viburnum rufidulum 40 153 77 2 12 0.12 325 87
Viburnum suspensum 30-200 30-200 20-75 7-25 20-200 0.12-3.0
Viburnum tinus Y, V 47-118 317 70 6 38 0.12 184 77
Viburnum x 'Eskimo' 90-107 115-234 39-86 8-11 51-54 0.12-0.30 180-220 61-80

Z (Gori et al., 2000; Mills and Jones, 1996; Robinson and Hamilton, 1980)
Y 227 kg/ha and 454 kg/ha applied - range given, V. plicatum spring and summer averaged, V. dentatum spring only
X Surface contamination of foliage from soil and presence of unavailable (physiologically inactive) and immobile iron in plant tissues limits the information value of iron measured by foliar analyses
W Leaf tissue analysis of Cu, Mn, and Zn may not be reliable indicators of Viburnum spp. nutritional status because foliage in commercial plant nurseries may be exposed to fungicides and nutrient solutions containing trace

elements, and trace levels of surface contamination may persist, even after leaves are washed
V Values for V. tinus 'French White' Na 1203 ppm and Cl 5033 ppm

127

Typical foliar tissue analyses results are provided for micro- and macronutrient observed, likely the result of increased heat stress. In addition, 9% more fertilizer leached
concentrations that may be determined by technical analyses of recently mature foliage from containers spaced at planting compared with those spaced mid-season, especially
collected from container grown viburnum plants (Table 5.4). In general, viburnums grow when CRFs were incorporated within the media, rather than top-dressed to the substrate
well when supplemented with a variety of nitrate (NO3) fertilizer forms and rates, but surface (Million et al., 2007a; 2007b).
viburnums are sensitive to ammoniacal forms of supplemented nitrogen. If provided Use of containers lined with the root growth regulator Spin Out™ (cupric hydroxide)
application rates of 200 ppm and 400 ppm NH4-N, most viburnum plants died or looked (SePRO Corp, Carmel, IN promoted secondary root branching in V. plicatum var.
very poor (Raker and Dirr, 1979). In addition to ammoniacal nitrogen sources, viburnums tomentosum ‘Mariesii’ and V. xrhytidophylloides ‘Alleghany’ with no signs of copper
are sensitive to excess (> 400 ppm) fertilization with urea based fertilizer, which will yield toxicity (Krieg and Witte, 1993). Viburnum odoratissimum, grown in containers treated
symptoms of marginal necrosis, foliar wilting and premature leaf abscission. If N is with Spin Out™ also developed improved root system architecture, but canopy quality was
supplied as calcium-nitrate-N (Ca(NO3)2), slight marginal necrosis can occur (Raker and not improved compared with plants grown in non-treated containers (Beeson, 1996).
Dirr, 1979). Viburnum odoratissimum grew sufficiently in Florida when a range of Season-long control of yellow nutsedge, morning glory, and honeyvine milkweed was
nitrogen rates from 3.0 to 5.7 g N per gallon container volume was applied using common achieved when the pre-emergence herbicide sulfentrazone (0.33 lbs ai/A) was combined
8-9 month controlled release fertilizer (CRF) plus micronutrients (Cashion and Yeager, with either Gallery 75WG (0.5 lbs ai/A), Pennant 7.8L (3.0 lbs ai/A), or Snapshot 80DF
1991). (2.0 lbs ai/A), without causing phytotoxicity among field-grown ‘Mohawk’ Viburnum
(Weston and McNiel, 1994). In another study, no phytotoxic affects were observed on
To determine if time of potting and fertilization application rate could influence viburnum foliage of container-grown V. tinus and root and shoot growth were unaffected when
cold hardness or plant growth, V. awabuki ‘Chindo’ were potted in July, September, tefluthrin (Fireban 1.5G) was applied to control imported fire ants at either 50 ppm or 150
October, March, and May, then the potting substrate was amended with either a 0.5X, 1X ppm (Lockley et al., 1995). Finally, some viburnum species, including V. rhytidophyllum
or 2X rate of CRFs (as polymer coated urea, ammonium nitrate and ammonium (Fargione et al., 1991), may occasionally be damaged by browsing deer.
phosphate), either all at once or with a split timing (Ivy et al., 2002). ‘Chindo’ viburnum
potted in September or October grew larger than plants potted in March, regardless of 128
fertilizer and rates of fertilization. ‘Chindo’ viburnum potted in September had
significantly greater N and P content in plant tissues compared to viburnum potted in
March or May. No plants were injured by winter temperatures experienced during the
study period regardless of potting date or rate of fertilization. In fact, plants potted in July,
September, or October had the highest substrate EC values in March, compared with plants
potted in either March or May, which in turn, had highest EC values in August, regardless
of fertilizer or rate of fertilization (Ivy et al., 2002). Nitrogen fertilization rate does not
affect degree of freeze injury, but the form of N applied does. Ammoniacal forms of N
predisposed doublefile viburnum (V. plicatum var. tomentosum) to freezing injury, as
evidenced by soft, brown cambial tissue on stems and the inability of vegetative buds to
resume active growth (Raker and Dirr, 1979). This might not be true of V. awabuki
‘Chindo’ because Ivy and colleagues (2002) used ammoniacal forms of N to supply
nutrients and reported no instances of freeze injury.

Plant spacing in nurseries also influences crop growth and resource use efficiency. To
achieve optimal spacing efficiency, plant canopies should not be arranged such that
individual canopies become isolated (Beeson and Yeager, 2003). For example, optimal
irrigation efficiency, defined as the highest proportion of water collected within the crop
canopy during overhead irrigation, was achieved in V. odoratissimum production blocks
when plants were grown at the minimum spacing required to produce saleable material
(Beeson and Yeager, 2003). Timing of plant spacing also effects resource uptake and
capture efficiency. When V. odoratissimum were spaced at planting instead of about mid-
season once canopies become developed, a 37% growth reduction in plant mass was

Table 5.1 Growth and horticultural characteristics of selected Viburnum species and cultivars currently in production in southeastern U.S. nurseriesu

Species Cultivar Size Form Flower Foliage Spring (S) Fruit Growth USDA Plant
(H’ x W’) and Fall (F) (Berries) Rate Hardiness

Zone

Deciduous shrubs

acerifolium - 4-6 x 3-4 Suckering thickets Yellow-white flowers, May-June Pastel pink to purple (F) Bright red, turn black, persists in Medium -
xbodnantense ‘Dawn’ 10 x 6 - Pale-pink buds, white flowers, fragrant Bronze fade to green (S) winter 5-7
bracteatum ‘Emerald Luster’ 10 x 8 Rounded, coarse textured White cymes, May Yellow to bronze (F) Red, turn black Medium 6-8
xbracteatum ‘Emerald Triumph’ Compact 3" wide cymes Maroon (F) Blue-black 4-7
6-8 x 6-8 - - Medium
Pink buds, white flowers, fragrant - Early red, black Slow to 5a
- 8-10 x 6-8 Upright, multi-stemmed moderate
- Slow to 4-7(8)
‘Anne Russell’ 5x5 Compact, densely twiggy, moderate 4
‘Chenaultii’ 10 x 10 rounded - 4
‘Compact Beauty’ unknown Rounded, less dense Slow 4
‘Fulbrook’ 8 x 10
Compact 2-3" white cymes, fragrant - - Medium 4-7a
4-7
xburkwoodii Upright, spreading -- Slow 5-8
5-7(8)
Pink buds, white flowers, fragrant, May - - Medium
4
‘Mohawk’ 7x7 Rounded 3" white cymes, clove-scented Yellow, orange, to red (F) Sparse red berries turn black persist Slow to
moderate (4)5-7(8)
(4)5-7(8)
‘Duvone’ 4x5 Compact Coral pink buds, white 1-2" cymes, fragrant Orange, scarlet & yellow (F) 1/2" long red to black Slow (4)5-7(8)
‘Cayuga’ (4)5-7(8)
xcarlcephalum - 8 x 10 Upright, spreading Pink buds, white 5" cymes, fragrant Orange-red (F) - Medium
carlesii Red, egg-shaped fruit (Sep-Oct) Slow to 4a-8b
- 10-15 x 10-15 Upright, rounded White 4-6" snowball cymes moderate 4a-8b
Pink-red buds, 2-3" white cymes, spice 3-8
‘Aurora’ 4-8 x 4-8 Rounded outline, dense fragrance Wine-red, muted purple (F) Red, turn black Slow 3-8
‘Diana’ 6-8 x 6-8 foliage 3-8
‘Compactum’ Rounded outline, dense Pink to red buds, 5" white cymes - - Slow 7-9
Spiced BouquetTM 6x8 foliage (2)3-8
Spice GirlTM Red buds, pink flowers - - Slow (2)3-8
Spice BallTM Compact habit Slow 4-8
4-8
3-4 x 3-4 Compact Rose pink buds, pink flowers - - Slow 4-8
5x6
7x7 Rounded outline, dense Reddish-pink flowers mature to blush white - - Slow
5x5 foliage
Rounded outline, dense - - - Slow
foliage White 2-5" cymes bronze-purple (S), yellow,
- orange, red, purple (F)
Compact, dense White Orange-red (F)
Small white
- 5-10 x 5-10 Upright, arching White cymes Red (F) pink, rose, blue-black concurrently Moderate

cassinoides ChallengerTM 5-8 x 5-8 Rounded Yellow, orange, to red (F) Green to pink then blue to black Moderate
DefenderTM Green to pink then blue to black Moderate
5-8 x 4-7 Upright, rounded Yellow to red (F) Abundant red Moderate
- Slow to fast
corymbiflorum - 8x8 Rounded

- 6-15 x 6-15 Varies

Autumn JazzTM 8-10 x 10-12 Multi-stemmed, vase White cymes Yellow, orange, to red (F) Blue to blue-black Fast
shaped
Black ForestTM
dentatum Blue BlazeTM 10-12 x 10-12 Upright rounded White flowers Burgundy (F) Blue-black Fast
Blue MuffinTM White 2-4" cymes, May-June Moderate
5x7 Low, spreading - Green, purple underneath (S) Blue Moderate

5-7 x 2-4 Upright - Blue, require cross pollination

129

Table 5.1 continued Growth and horticultural characteristics of selected Viburnum species and cultivars currently in production in southeastern U.S. nurseriesu

Species Cultivar Size Form Flower Foliage Spring (S) Fruit Growth USDA Plant
(H’ x W’) and Fall (F) (Berries) Rate Hardiness
-
Deciduous shrubs White cymes Moderate Zone
- Fast
CardinalTM 10-12 x 10-12 Upright Creamy-white cymes Red (F), unreliable in south Blue Fast 3-8
- Moderate 4-8
Chicago LustreTM 10 x 10 Rounded - Reddish purple (F), unreliable in south Blue-black Moderate 4-8
Cream-white with red speckles Slow 4-8
Crimson TideTM 10-12 x 10-12 Multi-stemmed, vase shaped - Red (F) - Slow 4-8
- Moderate 4-8
FireworksTM 6-7 x 4-5 Compact, columnar White cymes Ruby-red (F) Blue-black Slow 4-8
- Moderate 4-8
Indian SummerTM 8-12 x 8-12 Upright, rounded White cymes Orange-red (F) - Moderate 4-8
- Slow 4-8
Little JoeTM 4x4 Compact - Purple-green (F) - Moderate 4-8
Moderate 4-8
dentatum ‘Moonglow’ 8x8 Rounded White cymes, May-Jun, malodorous - Blue Aug-Sept. Moderate 4-8
Moderate 4-8
Northern BurgundyTM 10-12 x 8-10 Upright - Burgundy (F) - Moderate (4)5-7
- Slow 5-7
PapooseTM 5x5 Compact, rounded - Pink tinged new (S), gold-red (F) - Slow (4)5-7
- Moderate 5-7
PathfinderTM 5-6 x 3-4 Upright slender - Blue-black Slow 5-7
- Slow 5-7
‘Perle Blue’ 8-10 x 8-10 Rounded - Blue, abundant Moderate 5-7
- Moderate (4)5-7
Raspberry TartTM 4-5 x 4-5 Compact, rounded - Raspberry-red (F) Blue-black Slow 5-7
Abundant, May-summer Slow 5-7
Red FeatherTM 8-10 x 8-10 Rounded - Red-purple (S), burgundy-red (F) - (4)5-7(8)
Pink flowers, fragrant Moderate
Red RegalTM 8-12 x 8-12 Upright Pink buds, white 2-3" cymes, Mar- Reddish-orange (F) - 4-7
- 8-10 x 8-10, Apr, fragrant Red (F), unreliable in south Red, ovoid fruit (Sep-Oct), Moderate
‘Asian Beauty’ Upright, arching, compact, White 3-5" cymes, Apr-May, Russet-red (F) persistent y Moderate (3)4-7
10 x 10 rounded malodorous Cherry-red darken to black Moderate
- Moderate 4-7
Upright 4-7
- 4-7
Cardinal CandyTM 6x6 Rounded - - Glossy red, no pollinator 4-7
-
‘Catskill’ 5x5 Compact Yellow to red (F) Red mid-Aug to mid-winter

dilatatum ‘Erie’ 6 x 10 Rounded, mounded Yellow, orange, to red (F) Red, coral to pink after frost
‘Iroquois’ 9 x 12 Globose, dense Orange-red to maroon (F)
Red (F) Dark scarlet mid-Aug to
‘Michael Dodge’ 5x6 Rounded mid-winter
‘Mt. Airy’ 10 x 10 Upright, rounded
‘Oneida’ 10 x 10 - Bright yellow, large
‘Xanthocarpum’ Rounded, dense
‘Nanum’ 6x8 Rounded - Bright red
5x5
- Rounded, broad --
6-8 x 8-10
- Yellow to amber

farreri Reddish purple (F), unreliable in south Red-black, unreliable
xjuddii
- -
- 10-15 x 10-15 Rounded, upright
- Yellow, red, black (Aug-
lantana ‘Mohican’ 8x9 Compact Sept)
‘Aureum’ 8x8 Rounded - Orange-red, persistent (Jul-
‘Rugosum’ 10 x 10 Rounded, open Golden yellow new stems Sept)
‘Variegatum’ 10 x 10 Rounded, open - -
Yellow variegated
-

-

130

Table 5.1 continued Growth and horticultural characteristics of selected Viburnum species and cultivars currently in production in southeastern U.S. nurseriesu

Species Cultivar Size Form Flower Foliage Spring (S) Fruit (Berries) Growth Rate USDA Plant
Deciduous shrubs (H’ x W’) and Fall (F) Hardiness
hybrid
lantanoides Red BalloonTM 8x8 Rounded White cymes, Apr-May - Bright redz Moderate Zone
lentago - Red-scarlet (F)
luzonicum - 9-12 x 9-12 Rounded, spreading White 3-5" cymes Yellow, red, purple (F) Red to purple to black. Slow 4-7
macrocephalum - Reddish purple (F) 3-5(6)
macrocephalum f. 15-18 x 15-18 Rounded, upright, suckers White 3-4" cymes Yellow, pink, rose, blue-black Moderate
keteleeri - - 3-7
macrocephalum 12-15 x 12-15 Rounded, dense White 1-2" cymes, Apr, Red, sparsey Moderate 7-9
mongolicum - 12-15 x 12-15 Rounded, dense malodorous -
‘Sterile’ - Moderate 6-9
nudum ‘Summer Reflection’ White 3-8" lace-caps, Apr and
- fall 6-9
opulus ‘Brandywine’ 6-9
10-15 x 10-15 Rounded, dense White 5-6" lace-caps Shiny red to black 1/2" long Moderate -
plicatum ‘Count Pulaski’ 5-9
‘Earth Shade’ 12 x 12 Rounded, dense White 6-8" lace-caps, sterile - - Moderate 5-9
‘Pink Beauty’ 9 x 8 Oval, rounded
‘Winterthur’ 6-10 x 4-8 - Creamy-white, flat-topped cymes, Wine-red (F) Yellow to red (Aug), then Moderate 5-9
- 6-8 x 6-8 Round May black 5-9
‘Aureum’ Moderate 5-9
‘Compactum’ White 2-4" cymes, May Yellow, red, purple (F) Pink to blue (Sept), persist 5-9
‘Leonards Dwarf’ Slow (3)4-7(8)
‘Nanum’ 6-10 x 6-10 Round White flowers - Green to pink then blue to 4-7
‘Roseum’ or ‘Sterile’ black, heavy Moderate 4-7
‘Notcutt’ 6-10 x 6-10 Round White 6-10" cymes - Pink, bluish-lavender, 4-7
‘Xanthocarpum’ White Yellow, orange, to red (F) purplish black Moderate 4-7
- 6 x 5 Compact White Reddish purple (F) Moderate 3-7
‘Alfredo’ - Red (F) - Moderate 4-7
‘Bailey Compact’ 8x8 Round Fast 4-7
‘Phillips’ Pink, mature to blue-purple Moderate 3-7
Red WingTM black, persist Slow to moderate 3-7
‘Spring Red’ Slow 3-7
‘Wentworth’ Blue, abundant Slow to moderate 2-7
- Moderate 3-7
10-15 x 10-15 Rounded, thicket White 2-3" lacecaps Yellow, red, purple (F) Red (Sept-Oct), persist Moderate 3-7
Slow to moderate 2-7
12 x 10 Rounded - Yellow, fade to lime green (S) - Moderate to fast 5-7(8)
Slow to moderate
4-6 x 4-6 Dense - Red (F) Red, reliable Slow to moderate 131
Moderate
5-6 x 5-6 Rounded - Burgundy (F) Reddish-orange Moderate
Slow to moderate
2-3 x 2-3 Dense White, infrequent - Infrequent Moderate
Moderate
10-12 x 10-12 Rounded White 2-3.5" snowball cymes - -

12 x 12 Upright rounded Larger than species Maroon (F) -
- -
6-8 x 6-8 Compact, rounded White 3-4" lacecaps, May Yellow to red, purple (F) Yellow, persists, gold after
frost
10 x 10 Rounded, multi-stemmed
5-6 x 5-6 Dense, broad Red 1/3", persist
Compact
6x6 Upright - Red (F) -
8-10 x 8-10 Dense
8-12 x 8-12 Upright - Deep red (F) -
Rounded
3-5 x 3-5 - - Wine-red
6-10 x 6-10
White 3-4" cymes Red (F) Red, persist

- Orange-red (F) Infrequent

8-10 x 9-12 Rounded, horizontal - - Red, persist
Reddish purple (F) -
White 2-3" snowball cymes,
sterile, Apr

Table 5.1 continued Growth and horticultural characteristics of selected Viburnum species and cultivars currently in production in southeastern U.S. nurseriesu

Species Cultivar Size Form Flower Foliage Spring (S) Fruit (Berries) Growth USDA Plant
(H’ x W’) and Fall (F) Rate Hardiness

Zone

Deciduous shrubs

‘Rosace’ 8-10 x 9-12 Upright Medium pink-white cymes Bronze (F) - Moderate 5-7(8)
- Slow 5-7(8)
‘Leachs Compacta’ 6 x 6 Rounded Double white cymes Burgundy (F) - Moderate 5-7(8)
- Slow 5-7(8)
‘Mary Milton’ 8-10 x 9-12 Upright Pink snowball cymes - Moderate 5-7(8)
- Slow 5-7(8)
NewportTM 5-6 x 5-6 Mounded, dense White, loose snowball cymes Burgundy (F) Moderate 5-7(8)
‘Popcorn’ 8-10 x 9-12 Rounded, horizontal - - Moderate 5-7(8)
TriumphTM 5-6 x 6-8 Rounded, dense White 3" snowball cymes, profuse, - - Moderate 5-7(8)
early - --
- Moderate 5-7(8)
White, prolific Red, do not persist Moderate 5-7(8)
Moderate 5-7(8)
Sparkling Pink ChampagneTM 6-10 x 10-12 Rounded, horizontal Double-pink, profuse - - Moderate 5-7(8)
Moderate 5-7(8)
‘Rotundifolium’ 7-8 x 8-10 Rounded, horizontal - - Dark red (July) Moderate 5-7(8)
- Moderate 5-7(8)
‘Spellbound’ 8-10 x 9-12 Upright White, snowball cymes Red (F) - Moderate 5-7(8)
- Moderate 5-7(8)
plicatum - - - White 2-4" flat, sterile, Apr Reddish purple (F) - Slow 5-7(8)
‘Fireworks’ 8x6 Horizontal - Heavy fruiting, periodic Moderate 5-7(8)
‘Igloo’ 6 x 12 Broadly horizontal White 6" cymes, red interior, white - - Moderate 5-7(8)
outside Red (July) mature to black Fast
Heavy (June) Moderate 3-9
White 4-5" cymes, May Small Moderate 5-9
Small Moderate 3-9
‘Lanarth’ 12-14 x 12-14 Horizontal Ray flowers 2" wide - Pink-rose to bluish black, Moderate 3-9
Sept Moderate 3-9
‘Mariesii’ 10 x 12 Horizontal Ray flowers 1.75" - - (3)4-7
- Moderate
‘Molly Schroeder’ 8 x 5 Horizontal Pink flowers, persist - - Moderate 4-7
Typical (4)5-8
‘Nanum Semperflorens’ 5-6 x 5-6 Compact, horizontal White, persist - Moderate
Black (July) 5-9
‘Pink Beauty’ 6-10 x 5-7 Vase Deep pink, small, persist -
-
‘Roseum’ 6-10 x 5-7 Vase White fade to deep pink - Red to black (Aug-Sept) y

‘Shasta’ 6 x 10-12 Horizontal White 4-6" cyme, florets 1.5-2" wide - Blue 1/2"

‘Shoshoni’ 5 x 8 Compact, horizontal White 2-4" cyme -

‘Summer Snowflake’ 15 x 8 Upright White, Apr through summer (sporadic) -

‘Summer Stars’ 8 x 6-8 Broadly horizontal White, Apr through summer (sporadic) -
-
‘Summer Magic’ 15-18 x 20-24 Rounded, multi- White 2-4" cymes Bronze-red (F)
‘Forest Rouge’ stemmed

8-10 x 6-8 Upright - Red to pink (S), yellow to red (F)
- Purple-red (F)
prunifolium 8-10 x 8-10 Uniform

OvationTM 10 x 4 Columnar - Rosy-pink (S), yellow to red (F)

GuardianTM 10-12 x 6-8 Upright White cymes Crimson (F)
5-6 x 6-8 Compact White 1.5-3" cymes, Apr-May,
rafinesquianum - 5-6 x 6-8 Compact malodorous Russet-red (F)
‘Louise’s Sunbeam’ Red stems, bright yellow leaves
10-15 x 10-15 Rounded - (S)
xrhytidophylloides - 10-20 x 10-20 Rounded --
White 3-4" cymes, Apr
rufidulum - Rusty brown buds, cream-white 5" Maroon to burgundy (F)
cymes, Apr, fragrant

132

Table 5.1 continued Growth and horticultural characteristics of selected Viburnum species and cultivars currently in production in southeastern U.S. nurseriesu

Species Cultivar Size Form Flower Foliage Spring (S) Fruit (Berries) Growth Rate USDA Plant
(H’ x W’) and Fall (F) Hardiness

Zone

Deciduous shrubs

rufidulum Emerald Charm TM 10-12 x 8-10 Upright, rounded - Burgundy (F) - Moderate 5-9
sargentii Maroon to burgundy (F) - Moderate 5-9
opulus ‘Royal Guard’ 12 x 8 Upright, rounded - Yellow to red (F) Scarlet red (Aug-Oct)y Moderate (3)4-7
- Golden yellow Moderate (3)4-7
- 12-15 x 12-15 Rounded White 3-4" lacecaps. purple anthers, Dark maroon (S) - Moderate (3)4-7
malodorous - Striking Moderate (3)4-7
‘Flavum’ 8 x 6-8 Upright, vase
Yellow anthers
‘Onondaga’ 6-10 x 6-10 Upright, rounded
Maroon red buds, white flowers with
‘Susquehanna’ 10 x 10 Corky pink trace

Abundant

setigerum - 8-12 x 6-10 Upright, vase White 1-2" cymes, Apr Red (F), persistent Red 1/2" Moderate 5-7(8)
sieboldii - 15-20 x 10-15 Tree, upright White 2-3" cymes, Apr-May, fragrant Red (F), unreliable in south 4-7(8)
trilobum IroncladTM Abundant Green-burgundy (F) Bright red, pink, rose-red Fast 4-7(8)
‘Seneca’ 15 x 12 Tree, upright - - (Aug-Oct) 4-7(8)
‘Hahs’ 15-20 x 15-20 Tree, upright - Deep red (F)
- Moderate 2-7
6-8 x 6-8 Rounded
Large red, pendulous, Moderate
persists 3 months

Red, persist Moderate

wrightii - 6-10 x 6-10 Upright, rounded White 2-4" cymes, Apr-May Red (F) Red (Aug), persist Moderate 5-7
‘Hessei’ 6-8 x 6-8 Rounded - - Moderate 5-8
Brilliant red (Aug-Sept),
persist

Evergreen shrubs

‘Susy’ 6-7 x 5 Upright, mounded Profuse white, fragrant - Red, turn black Fast
‘Nantucket’
carlesii x PearlificTM 12 x 6 Upright, compact Profuse white, slightly fragrant - Red, turn black Slow to moderate 5-7(8)
carlcephalum ‘Conoy’
- 5x6 Compact White, slightly fragrant - Red, turn black Slow - 6a-8
xburkwoodii ‘Jermyns Globe’ (7)8-9
davidii 5-6 x 6-8 Compact Pink buds, 2-3” white, fragrant Mar-Apr Maroon (F) Small red, turn black Slow to moderate
xglobosum 5-7
3-5 x 3-5 Compact, mounded Pink buds open to white 2-3" cymes, - blue 1/4" berries, persist y Slow
Apr-May

5-10 x 5-10 Rounded, dense Pink buds and flowers, fragrant - Red-black, unreliable Moderate

- 15-20 - Cream-white 3-6", Apr-May, fragrant - Red to purple to black. Fast 8b-10a

‘Irvini Sweet’ 25 x 20 Upright White - - Fast 8b-10a

odoratissimum ‘Red Tip’ 25 x 20 Upright - Reddish-green new shoots (S) - Fast 8b-10a
Red, turn black x Moderate 7a-9b
Handsome DevilTM 9x8 Rounded White, June Burgundy, orange-bronze hues Red, infrequent Fast 7-10
(S, F)
‘Chindo’ 15-25 x 10-15 Upright, dense, pyramidal White, infrequent
-

- 10-15 x 10-15 Rounded White 4-8" flat cymes, Apr - Red to black y Moderate (5)6-8

rhytidophyllum ‘Cree’ 8x8 Compact Abundant - Red to black, persist Moderate (5)6-8

‘Green Triumph’ 8x8 Compact - - - Moderate (5)6-8

133

Table 5.1 continued Growth and horticultural characteristics of selected Viburnum species and cultivars currently in production in southeastern U.S. nurseriesu

Species Cultivar Size Form Flower Foliage Spring (S) Fruit (Berries) USDA Plant
‘Willowwood’ (H’ x W’) White 6" cymes, spring and fall (south) and Fall (F) Growth Rate Hardiness
Evergreen shrubs
xrhytidophylloides Zone

15 x 10 Arching -- Moderate

suspensum - 6-12 x 6-12 Rounded White, pink-tinged cymes, Feb, fragrant - Red, infrequent Fast

tinus - 6-12 x 6-8 Upright, oval Pink buds, white 2-4", Feb-Apr fragrant - Metallic blue y Moderate

‘Bewleys Variegated’ 6-7 x 6-7 Rounded - Cream variegations - Moderate (7)8-10
fade to soft yellow

‘Compactum’ 4-6 x 4-6 Rounded - -- Moderate (7)8-10

tinus ‘Gwenllian’ 10 x 10 Rounded Dark pink buds, blush-pink flowers - - Moderate (7)8-10
- Moderate (7)8-10
‘Robustum’ 15 x 15 Upright, dense Blush white flowers -

‘Spirit’ 6 x 6 Compact Red-purple buds, white flowers - - Moderate (7)8-10

‘Spring Bouquet’ 6 x 6 Rounded Dark red buds, white flowers - - Moderate (7)8-10

Semi-evergreen shrubs

carlesii x carlcephalum ‘Chesapeake’ 6 x 10 Compact, mounded Pink buds, white 2" cymes, fragrant - - Slow to moderate 6a-8
‘Eskimo’ 5x5 - Sparse, dull red to black Medium 5b
8 x 10 Compact, dense Cream-pink buds, white 3-4" snowball cymes Maroon to red (F) Dark red (Aug), persist w Moderate 6-8(9)
7x9 Purple (F) Red (Aug) v Slow to moderate 6a-8(9)
hybrid ‘Chippewa’ Multi-stemmed, dense White 4-7" cymes, Apr-May
‘Huron’
Multi-stemmed, dense White 4-6" cymes, Apr

‘Small’ 12 x 12 Upright, rounded White 1.5-2.5" cymes - Red to shiny black, small Moderate 6-9

‘Densa’ 4-5 x 4-5 Compact, dense - Red in winter - Moderate 6-9

obovatum ‘Mrs. Schillers Delight’ 2x5 Compact, dense White, abundant - - Slow 6-9
‘Reifler’s Dwarf’ 4x5 Compact, dense White, abundant Purple (F) - Slow 6-9

‘St. Pauls’ 12 x 8 Loose, open White, sparse -- Moderate 6-9

‘Whorled Class’ 3 x 4 Compact, dense White, sparse -- Slow 6-9

xpragense - 8-10 x 6-8 Pyramidal Pink buds, 3-6” cymes, creamy-white 3-6", Apr - Red, infrequent Fast 5-8
‘Decker’ 8-10 x 6-8 Pyramidal -- - Fast 5-8

xrhytidophylloides ‘Alleghany’ 11 x 11 Rounded Abundant, May - Bright red (Sept-Oct) Moderate (4)5-8
Darts DukeTM 8-10 x 8-10 Rounded White 6" cymes, spring and fall - - Moderate (4)5-8

z Cross pollinate with ‘Mohican’ or V. rhytidophylloides ‘Alleghany’
y May require cross pollination
x V. odoratissimum pollinator
w Cross-pollinate with 'Huron'
v Cross-pollinate with ‘Chippewa’
u Krüssmann 1984; Dirr, 2007 and 2013

134

SECTION 2 Several abiotic disorders can be induced by winter cold; these disorders can be confused
with pest injury or plant diseases. Once cold damage occurs, viburnum plants will be
Abiotic Stressors predisposed to injury both by opportunistic arthropod pests and infection by plant diseases.
Managers who can discriminate pest injury and plant appearance caused by abiotic
© Sarah White, CU disorders will be able to limit unnecessary pesticide applications that would result from
Figure 5.7 Tender foliage and buds of V. lantana damaged by a late spring freeze in SC misdiagnosis of the problem.

ABIOTIC STRESSORS Winter Burn
Winter burn or scorch is a common problem on evergreen shrubs and trees and may be
1. Winter Burn more of a concern for containerized plants than field-grown or landscape transplanted
2. Bark Cracking and Sunscald plants. Winter burn appears as desiccated leaf margins and will be most pronounced on the
3. Water Quality: Boron and Salinity sunward or windward sides of the plant. Because evergreen foliage continues to lose
4. Ozone Injury moisture during winter, injury is particularly bad following clear, cold sunny winter days
when the ground is frozen and plant roots cannot absorb water to replace that which is lost
through transpiration (Relf and Appleton, 2009). Buds of V. lantana are susceptible to
injury caused by freezing temperatures (Figure 5.7). If stress from high soil or substrate
salt (NaCl) concentrations (see below) occurs, V. lantana tissues were more likely to be
damaged, especially when cold stress occurs late in spring (Zimmerman et al., 2005).

Bark Cracking and Sunscald
Excess nitrogen fertilizer or unseasonably warm temperatures can cause plants to remain
actively growing too late in the season and as a result the basal portion of the trunk does
not sufficiently harden before cold weather (Hartman et al., 2000). Frost cracking and
sunscald appear most likely on wood from the south or southwest sides of exposed trunks
and limbs because these exposures experience the greatest winter temperature fluctuations.
Vertical frost cracks that appear in bark, particularly on thin barked trees and shrubs,
usually become evident in the spring but may have originated from freezing conditions
experienced from the late fall throughout early spring. Where sunscald occurs, sunken or
discolored bark may precede bark splitting. Split bark and trunk cracks will generally
close and heal, often leaving callus tissue formation as evidence of past injury. However,
affected shrubs may not be marketable at point-of-sale. Damaged plants can also become
susceptible to subsequent pest and plant disease problems.

Management
In areas where winter burn has been a problem, evergreen shrubs and trees should be
planted in early fall, which will allow roots to become established and optimally hydrate
the plant prior to the onset of freezing conditions and drying winds (Adkins et al., 2010).
Managers should plan for regular irrigation in the fall to increase water availability to
newly planted shrubs. Avoid bark cracking in production by reducing irrigation and
nitrogen availability towards the end of the growing season, e.g. September 15 in middle
Tennessee, to prevent succulent growth late in the season (Adkins et al., 2010; Fulcher,
2013). Summer applications of top-dressed or soluble fertilizers should be timed so that
these products will not continue releasing nitrogen too late in the season. Most CRFs
release less nitrogen during colder temperatures. Sunscald can be prevented by wrapping

135

the trunks of young trees in November with a commercial tree wrap in which the insulating © Gail Zawacki, Wits End Blogspot
paper mitigates temperature fluctuations. Wraps must be used carefully as they can lead to Figure 5.8 Typical stippling damage on viburnum foliage after
other problems, such as harboring insect pests. Anti-desiccants have not been found to exposure to ozone
consistently benefit plants during transplanting (Relf and Appleton, 2009).
136
Water Quality: Boron and Salinity Related Injury
Symptoms of boron toxicity in V. tinus include development of yellow to orange spots on
the leaf tips of new foliage and leaf margins along older leaves within the canopy. These
symptoms are likely to develop only when boron concentrations exceed 6 ppm. As
symptoms advance with sustained exposure to boron, affected leaves curled inward and
prematurely senesced (Bañon et al., 2012). Viburnum davidii is highly sensitive to
rhizospheric salt stress (either as Na or Cl) and does not recover quickly from stress
induced by exposure to salt. Viburnum tinus is similarly sensitive to rhizospheric salt
exposure, yet recovered slightly after the salt leached from its root system (Devecchi and
Remotti, 2004). By contrast, V. recognitum (formerly V. lucidum) grown under increasing
salt stress regimes of 1.4, 4.4, and 7.4 dS/m for 6 months displayed few visual foliar
symptoms, even at the highest exposure levels. Viburnum recognitum tolerated salt
exposure by limiting salt uptake into shoot tissues (Cassiniti et al., 2009). Exposure of salt-
sensitive V. tinus to 6 dS/m salinity induced necrotic lesions on leaves, preceded by foliar
wilting that started at the leaf tips and spread to the center of the leaf blade. Leaves curled
inward and were eventually dropped. Viburnum tinus growth was reduced by 12% when
exposed to boron and by 60% when exposed to salinity in comparison with unexposed
control plant comparisons (Bañon et al., 2012).

Water quality management
Fox and others (2005) determined that reclaimed water containing > 0.75 dS/m salinity
could be safely used for landscape irrigation of V. tinus ‘Compactum’, which provided
visual quality ratings similar to plants irrigated with potable water. Maximum exposure
concentrations of 2 dS/m salinity and 1 ppm B are recommended to maintain commercial
value of V. tinus (Bañon et al., 2012). Cassaniti and colleagues (2009) used irrigation
water applied via drip emitters at a rate 0.5 gal/hour and applied until a 50% leaching
fraction was reached to mitigate salt concentrations. Limiting salt accumulation in the root
zone by increasing leaching may be an important irrigation management strategy,
particularly when poorer quality water sources are used.

Ozone Related Injury
Symptoms of ozone sensitivity in viburnum include seasonally premature reddish
coloration to upper leaf surfaces, often paired with inter-veinal stippling (Figure 5.8). As
injury progresses, reddish stippling can cover the majority of the upper leaf surfaces
(Novak et al., 2008). Viburnum tinus tolerated ozone exposures of 200 ppb for 5 hours
without injury symptoms, while V. lantana plants were much more sensitive and
demonstrated foliar sensitivity after exposure to 21.8 to 41.5 ppm per hour ozone
(Lorenzini et al., 1999).

SECTION 3 Most viburnum species and cultivars are A
considered to be "trouble-free" and generally B
Arthropod Pest Management support very few pests and plant diseases that
cause significant or lasting aesthetic injury
(Dirr, 2007; Johnson and Lyon, 1991). Despite
the pest tolerance and durability of viburnums,
diverse pests and plant diseases are capable of
causing injury in the southeastern U.S. Pest-
specific insecticidal activity and Insecticide
Resistance Action Committee (IRAC, 2013)
codes can be used to develop a pesticide
rotation plan to manage key viburnum pests
(Table 5.5, at end of section 3). A list of
viburnums resistant to viburnum leaf beetle
(see below) are provided (Table 5.6). Life stage
and seasonal activity of primary pests of
viburnum are provided based on normal
monthly occurrence in USDA Plant Hardiness
Zone 7 (Table 5.7).

Viburnum Leaf Beetle C

The native range of viburnum leaf beetle

[Pyrrhalta viburni (Paykull)] extends across

most of Europe. This leaf beetle (Coleoptera:

Chrysomelidae) has become an invasive pest of

viburnum species in northeastern North

America. First encountered in North America

© William Klingeman, UT in 1947 in Ontario, Canada, breeding © William Klingeman, UT
Viburnum leaf beetle damage
populations causing severe defoliation of Figure 5.9 Adult viburnum leaf beetle
COMMON ARTHROPOD PESTS ornamental viburnum were not discovered until (A) feeding on foliage, skeletonizing
1978 in the Ottawa/Hull region of Canada. It leaves (B), and eventually causing
was first detected in the U.S. in 1996 in Cayuga branch dieback (C)
County New York, where extensive larval

feeding was occurring on the native V. dentatum

1. Viburnum Leaf Beetle 8. Oystershell Scale complex. This pest has spread into many parts of Ontario, the Canadian Maritime
2. Japanese Beetle 9. Clearwing Borers
3. Cranberry Rootworm 10. Dogwood Tree Borer Provinces, Maine, New York, Pennsylvania, Vermont, Massachusetts, and Ohio (Weston et
4. Four-Lined Plant Bug 11. Thrips
5. Aphids 12. Southern Red Mite al., 1999).

Adult viburnum leaf beetles are ¼ inch-long with a brownish head, thorax and elytral wing
covers. The dorsal (top) surface has a thick, golden-grey pubescence (Weston et al., 1999).
Larger than adult beetles, 0.24 to 0.36 inch long viburnum leaf beetle larvae are elongate
and with a shiny, greenish-yellow body covered with black dots (Figure 5.9A; Barr and
Hoover, 2011). Both larvae and adults feed on viburnum foliage. Eggs hatch by early to
mid-May and the resulting larvae skeletonized the foliage (Figure 5.9B), devouring all but

137

the midribs and major veins. Adults emerge by early July and make irregular circular holes Japanese Beetle1 A
in the foliage. The adults feed on foliage until the first killing frost in the fall. Adult Adult Japanese beetles, Popillia japonica Newman
females chew holes in small branches in which to deposit their egg clusters. It takes 8 to (Figure 5.10A), attack flowers, fruits and foliage of © Amy Fulcher, UT
10 weeks for the insect to develop from egg hatch to adult emergence (Weston et al., 1999). more than 300 species of plants including viburnum. B
Since its introduction in 1916 via infested nursery
Defoliation, branch dieback and shrub death can occur under heavy infestations, especially stock, Japanese beetles have become one of the most © David Cappaert, MSUBugwood
when injury persists for two or more years (Figure 5.9C). Viburnum leaf beetle has a damaging pests in the eastern U.S. (Held, 2004). Figure 5.10 Adult Japanese beetle
strong preference for V. dentatum, V. opulus, V. opulus var. americanum, and V. Adult beetles are 0.3 to 0.4 inch (8 to 11 mm) long (A) feeding on foliage and
rafinesquianum (Table 5.6). Species most resistant include V. carlesii, V. xburkwoodii, V. and metallic green and copper-brown in color. They eventually skeletonizing leaves
plicatum var. tomentosum, V. xjuddii, V. rhytidiophylloides, and V. rhytidiophyllum (Weston are active day fliers that disperse readily across long and Japanese beetle grubs (B)
distances. Japanese beetles require one full year to
et al., 2000). Other less susceptible viburnum species include tea viburnum (V. setigerum), complete egg to egg development. Larvae, or white
Japanese snowball (V. plicatum), Siebold viburnum (V. sieboldii), and carlcephalum grubs, feed on roots of turfgrasses and other
viburnum (V. xcarlcephalum; Table 5.6). susceptible plants (Figure 5.10B). Up to five dozen
eggs per female are deposited into moist soil, hatch
Management and develop through three instars. Third instar larva
In addition to use of resistant and tolerant viburnum species (Table 5.6), fertilization rates overwinter and pupation occurs in the spring. Adult
can be reduced to limit herbivory by viburnum leaf beetles. For example, containers of V. beetles emerge in early summer, usually following a
dentatum shrubs could be maintained using less than 0.75 oz per ft3 (1.3 lbs N per yd3) N rainfall event. They are highly mobile and
fertilization. When N fertilization levels were kept below this rate, Surround WP, a kaolin gregarious, capable of rapidly defoliating susceptible
clay-based wettable powder, effectively lowered foliar feeding injury and egg mass plants. On viburnum, adult beetles skeletonize leaves
numbers in experimental trials (Schultz et al., 2007). Surround WP is an OMRI certified (Figure 5.10A).
organic pest management control product. Viburnum species are not specifically listed on
the label. Viburnum leaf beetles can be controlled where they occur with insecticide sprays Management
or soil drenches of systemic insecticides (Table 5.5). Applications should target larvae Traps used for monitoring include both a floral lure and sex attractants that are intended to
when they become active in the spring and any adults after emergence in early summer. help track first flight of adult Japanese beetles. Traps should be placed at least 200 feet
(61.0 meters) away from plants under protection. Because only a fraction of lured beetles
Table 5.6 Susceptibility of Viburnum species to colonization by the viburnum leaf beetle, are caught in traps, trapping is ineffective for managing beetles, but does serve as a
Pyrrhalta viburni (McNeil et al. 2000, Weston and Desurmont, 2002) monitoring tool. Japanese beetle adults on susceptible plants can be controlled with foliar
applications of short-residual insecticides that require repeated applications to maintain
Viburnum species Common name Viburnum species Common name uninjured plants during adult flight periods. Systemic insecticides can provide longer
residual control (Table 5.5). Follow the National Plant Board’s U.S. Domestic Japanese
Most susceptible Particularly resistant Beetle Harmonization Plan when shipping nursery stock from areas that may be infested
with Japanese beetles to beetle-free areas (http://www.nationalplantboard.org/docs/
V. dentatum Arrowwood V. xburkwoodii Burkwood jbcolumn.pdf) (NPB, 2013).

V. opulus European cranberrybush V. carlcephalum Fragrant
V. rafinesquianum
V. sargentii Downy-leaved V. carlesii Koreanspice
arrowwood
V. xjuddii Judd
Sargent V. plicatum Doublefile

V. trilobum American cranberrybush Predation by birds, small mammals and generalist insect predators also can reduce
Japanese beetle populations. Two wasp species (Tiphia vernalis Rohwer and T.
Moderately susceptible V. xrhytidiophylloides Lantanaphyllum popilliavora Rohwer) parasitize larvae underground, and a tachinid fly, Hyperecteina
aldrichi (Mesnil) attacks adult beetles. The bacteria Bacillus popilliae exclusively attacks
V. acerifolium Mapleleaf V. rhytidiophyllum Leatherleaf
V. dilatatum Linden V. setigerum Tea
V. lantana Wayfaring tree V. sieboldii Siebold

V. lentago Nannyberry 1 Discussion of Japanese beetles (Popillia japonica) is largely reprinted from text prepared for Optimizing
V. xpragense Prague plant health and pest management of Lagerstroemia spp. in commercial production and landscape situations
V. prunifolium Blackhaw in the Southeastern U.S.: A review (Chappell et al. 2012. J. Environ. Hort. 30(3): 161-172). Reprint of this
content herein is made possible by permission of the original content authors.

138

Table 5.7 Seasonal activities of the major arthropod pests of Viburnum in the mid-southern U.S., and unless otherwise noted, represent
occurrence in USDA Plant Hardiness Zone 7. Depicted activity may be early or later than shown depending on location. Activities
represented in the table are scale insect crawler emergence, as well as adult or nymphal activity of the most common insect and mite
pests. Peaks in arthropod feeding injury and pest abundance, when reported are denoted by ‘D’ and ‘P’, respectively

D

P © Sridhar Polavarapu, Rutgers

Z Viburnum leaf beetle activity is based on observations in New York where it has become widespread, thus reflects seasonality primarily within USDA Figure 5.11 Cranberry rootworm larvae and
Plant Hardiness Zones 4b and 5a pupa (middle) infected with. H. bacteriophora

Japanese beetle larvae, but it is best suited for large scale, regional application rather than 2 weeks after emergence, and then seek refuge in leaf litter where they deposit eggs.
individual site applications. Microscopic entomopathogenic nematodes occur naturally in Larvae are active root feeders (Oliver and Chapin, 1980).
the soil, and, together with a symbiotic bacterium, can ultimately kill larvae by means of
septicemia. Nematodes that have been shown to be most effective against Japanese beetle Management
larvae are Steinernema glaseri (Steiner) and Heterorhabditis bacteriophora Poinar. The Pesticides may provide control when beetles are actively feeding (Table 5.5). A fraction of
latter is commercially available. applications can also be directed toward leaf litter and debris beneath the affected plant
where nocturnal beetles will hide. Entomopathogenic nematodes including
Cranberry Rootworm2 Heterorhabditis bacteriophora Poinar and Steinernema scarabei (Stock & Koppenhöfer)
Cranberry rootworm [Rhadopterus picipes (Olivier)] is a chrysomelid leaf feeding beetle have shown some potential for cranberry rootworm control (Polavarapu, 1999; van Tol and
widely distributed east of the Mississippi River. Adults and larvae of this nursery and Raupp, 2005).
landscape pest have an extremely broad host plant range. In addition to viburnum species,
cranberry rootworm feed on camellia (Camellia sp.), cherry laurel (Prunus laurocerasus), Four-Lined Plant Bug
golden rain tree (Koelreuteria paniculata), Japanese holly (Ilex crenata), Chinese holly The four-lined plant bug, Poecilocapsus lineatus (Fabricius), is a native and widespread
(Ilex cornuta), magnolia (Magnolia sp.), oaks (Quercus sp.), redtips (Photinia sp.), generalist feeder with host plants including more than 250 species across 57 plant families.
Rhododendron sp., roses (Rosa sp.), silver maple (Acer saccharinum), sycamore (Platanus Host preferences are for several dicots including many herbaceous and woody ornamental
sp.), sumac (Rhus sp.), sassafras (Sassafras albidum), and Virginia creeper (Parthenocissus plants. Azalea (Rhododendron sp.), deutzia (Deutzia sp.), dogwood (Cornus sp.), forsythia
quinquefolia). Adult beetles are about 0.2 inches (0.51 cm) long, dark brown, and shiny (Forsythia sp.), Amur maple (Acer ginnala), rose, sumac and weigela (Weigela florida), in
(Figure 5.11). Adults bear one brood per year and emerge from late April to mid-May in addition to viburnum, are occasionally attacked (Johnson and Lyon, 1991). Feeding on
Mississippi (Harman, 1931; Oliver and Chapin, 1980; Johnson and Lyon, 1991). Adults shade trees is generally restricted to juvenile sucker and water sprouts (Wheeler and Miller,
are nocturnal feeders, hiding in leaf litter and debris during the day. Adults feed for about 1981). Feeding injury is caused by lacerate-flush feeding, in which barbed stylet
mouthpart tips are used to slice and tear plant cells beneath the leaf surface. Softer leaf,
2 Discussion of cranberry rootworm (Rhadopterus picipes) is largely reprinted from text prepared for bud and flower parts are preferred, but seed, stem and root tissues may also be affected
Management of pests, plant diseases and abiotic disorders of Magnolia species in the Southeastern U.S.: (Schuh and Slater, 1995). The feeding pocket in a leaf is flooded with saliva and digestive
A review (Knox et al., 2012. J. Environ. Hort. 30(4): 223-234). Reprint of this content herein is made enzymes that liquefy rigid parts of the ruptured cells before fluids are ingested. Injury may
possible by permission of the original content authors.
139

A take several days to become widely are about 0.1 in (2.5 mm) long and bluish, dusty white (Figure 5.13A; MacGillivray, 1960).
apparent and can be misidentified as shot- Their multivoltine life-cycle includes secondary host plant(s), which are not yet known
holes caused by fungal pathogens. Feeding (Johnson and Lyon, 1991). Snowball aphids overwinter on viburnum host plants. In fall,
points darken then are transformed into mature C. viburnicola lay eggs on twigs and buds of viburnum species. Spring egg hatch
small, nearly transparent “windows” of just coincides with viburnum bud break, allowing pale pink to purplish nymphs to feed on
clear upper and lower leaf tissues (Figure newly expanding plant tissues (Johnson and Lyon 1991). Foliar feeding to several native
5.11A). With time, clear windows coalesce viburnum species results in rapid and severe contortion of leaves, bent stems, and
into a necrotic patch that drops from the shortened internodes (Figure 5.13B-D; MacGillivray, 1960; Johnson and Lyon, 1991); V.
leaf to leave a shot hole. plicatum var. tomentosum appears to be resistant to these malformations (Johnson and
Lyon, 1991). About two months after egg hatch, C. viburnicola emigrate from viburnum
Adult four-lined plant bugs are extremely onto alternate host plants. In about September, winged migrant adults return to viburnum,
B mobile and are readily recognizable from give birth to live young without mating (parthogenesis), which in turn, becomes a sexual
generation that lays eggs for the overwintering generation (MacGillivray, 1960; Johnson
the black and yellow stripes on the and Lyon, 1991). Viburnum aphids (Aphis viburniphila Patch), which also feed on
AB
hemelytra (Figure 5.12A, inset). Newly
© D.K.B. Cheung
hatched four-lined plant bug nymphs are CD

reddish-orange with black spots. Older © Bill Klingeman, UT
Figure 5.13 Snowball aphid adult (A), healthy growth above aphid feeding damage (B),
instars have black wing pads with a yellow and typical contortion of leaves and internode from foliar feeding (C, D)

stripe on each pad (Figure 5.12B). 140

Nymphs hatch in mid- to late-spring from

banana-shaped eggs deposited the previous

© Frank Hale, UT fall. Eggs are deposited at right angles in

Figure 5.12 Characteristic damage from 50 to 75 mm (2 to 3 in.) long vertical slits
four-lined plant bug feeding on leaves (A) along host plant stems (Johnson and Lyon,
with adult (inset) four-lined plant bug 1991; Wheeler and Miller, 1981). Clusters
feeding and (B) older instar with black wing of six or more four-lined plant bug eggs
pads each with a yellow stripe can be laid in cinquefoil (Potentilla sp.),
loosestrife (Lythrum sp.), and rose campion

(Lychnis coronaria) that may serve as

refuge resources (Wheeler and Miller, 1981). Nymphs stay near hatching sites and within

about one month, complete metamorphosis to adults. There is typically only one

generation of P. lineatus per season.

Management
Deciduous plants can be scouted once they lose their leaves in fall. Infested plant portions
can be manually pruned and discarded (Johnson and Lyon, 1991). Trap crops, including
mints, can be used in crop borders to protect sensitive crops and landscape beds (Filotas
and Westerveld, 2011). Scout for feeding injury and live four-lined plant bugs in late May
or early June. Insecticides for managing four-lined plant bugs include both broad-
spectrum, persistent pesticides that can eliminate beneficial arthropod predators in the
garden and landscape, as well as alternatives less toxic to natural enemies (Table 5.5).

Aphids
In the eastern U.S. and Canada, two aphid species are common pests of viburnum. Mature
snowball aphids [Ceruraphis viburnicola (formerly Neoceruraphis (=Aphis) viburnicola]

viburnum species, may be active through much of the year. Aphis viburniphila feeding Management actions for scale insect pests are best timed to coincide with visual
differs from C. viburnicola by not producing visible leaf or stem deformation (Johnson and confirmation of crawler emergence and activity. Degree-day models indicate that
Lyon, 1991). oystershell scale eggs hatch following accumulations of about 760 degree-days using a
40°F base temperature (Mussey and Potter, 1987) or about 360 degree-days using a 50°F
Management base temperature (Herms, 2004). Double-sided sticky tape can be used to monitor and
Although viburnum aphid infestations do not cause a long-term decline in plant health, C. confirm egg hatch and crawler movement. Plant flowering phenology also helps to gauge
viburnicola foliar distortion is persistent on shrubs, can be aesthetically unpleasant, and degree-day accumulations and may assist with reducing confusion related to appropriate
may limit access to cutting stock for propagation. In seasons providing warm, wet base temperature selection. Oystershell scale crawlers have been observed in Ohio and
conditions, entomopathogenic fungi (e.g., Beauveria bassiana) can restrict aphid Kentucky when eastern redbud (Cercis canadensis), flowering dogwood (Cornus florida),
population growth. In structurally diverse and ecologically complex landscape habitats, Japanese flowering crabapple (Malus floribunda), Sargent’s crabapple (Malus sargentii),
natural enemies may reduce need for active aphid management. Ants are commonly lilac (Syringa vulgaris) and doublefile viburnum (Viburnum plicatum var. tomentosum)
associated with aphids and feed on excreted honeydew. In turn, monitoring for ant activity have begun to flower (Mussey and Potter, 1987; Herms, 2004).
in viburnum crops and landscape plantings can help with early detection of small aphid
populations that can be spot treated. Ladybeetles, lacewings, syrphid flies and parasitic Oystershell scales feed on woody tissues of viburnum, therefore, pesticide treatments
wasps all feed on aphid adults and nymphs, yet may be killed if broad spectrum contact
insecticides are used. including azadirachtin, horticultural oil, insect growth regulators (buprofezin and

When aphid infestations are large, topical insecticide applications provide effective control pyriproxyfen), and some neonicotinoids (acetamiprid, dinotefuran) will be most effective
(Table 5.5). Monitor contact treatment efficacy on a weekly or biweekly basis and re-treat
hot spots to prevent re-establishment. Systemic insecticides that move into plant tissues when applied to crawlers shortly after peak crawler emergence (Table 5.5). These products
slowly and provide long residual aphid control.
can be used to conserve natural enemy populations (Rebek and Sadof, 2003; Raupp et al.,
Oystershell Scale
Oystershell scale [Lepidosaphes ulmi (L.)] is the principal scale insect pest associated with 2006; Frank and Sadof, 2011). Acephate,
viburnum species in the eastern U.S. (Johnson and Lyon, 1991). Oystershell scale is an
armored scale broadly distributed across the U.S. that, in addition to viburnum, feeds on A chlorpyrifos and malathion have also been
twigs and branches of more than 100 plant species. Severe infestations may cause branch effective at managing armored scale
die-back. Because female oystershell scales are about 0.098 inch (2.5 mm) long and blend
in with bark colors, detection is difficult (Figure 5.14). Oystershell scale crawlers emerge insects on ornamental plants, including
in April in Kentucky (Mussey and Potter, 1997), May in Michigan and Ohio (Herms,
2004), and May and July (two generations) in Virginia (Day, 2009). Emergence coincides viburnum. If using contact insecticides
with first flowering of Vanhoutte spirea (Spiraea xvanhoutii) (Herms, 2004).
such as pyrethroids and organophosphates
Management
Armored scale insects such as oystershell scale are difficult to control. Good sanitation (e.g., carbaryl, chlorpyrifos), monitor to
practices are important for preventing scale insect outbreaks. Prune infested stems from
lightly infested plants and remove cut tissues and dead plants from the production area. preempt scale outbreaks that can result
Debris including senesced leaves and pruned stems should be destroyed to ensure scale
insect crawlers will not emerge to re-infest host plants. Dead scales do not fall from plants; when natural enemies are killed while
thus, to determine if pesticide treatments are necessary or were effective in controlling
scales, crush the waxy covering. When crushed, gut contents extrude from live armored surviving mature armored scales persist
scale insects.
© Darren Blackford, USDA-FS Bugwood and reproduce (McClure, 1977; Raupp et
al., 2001).

B

Dormant-season horticultural oils can be

applied to dormant viburnum in winter and

early spring. Control with oil is likely

achieved through both impaired respiration

and disruption of cellular membranes in

treated arthropods. Follow-up applications

of dormant oil, after leaf drop and before

bud swell in fall and early winter, will also

© W. Seidel, U of MN help reduce armored scales population
growth by limiting impact of subsequent

Figure 5.14 Closeup of oystershell scale generations. Check the label to be sure

adult (A) and viburnum infested (B) with that phytotoxicity is not noted (e.g., from

oystershell scale use of dormant season horticultural oil)

141

AC Female clearwing moths deposit eggs directly onto bark of viburnum host tissues. Once
eggs hatch, larvae enter wound tissues or penetrate directly into the bark. Larvae are
© D.K.B Cheung © David Parsons, U of WI cream-colored (S. fatifera) or pinkish (S. viburni) and have a hardened, or sclerotized, head
B capsule (Figure 5.15A). Lesser viburnum borer prefers to feed within stems, while S.
viburni develops within wound-related swollen branches or galled tissues (Solomon, 1995).
© David Parsons, U of WI Bugwood Bugwood Developing larvae feed on callus tissues or on the cambium causing foliar chlorosis, shoot
wilt, loss of plant vigor and even plant death (Engelhardt, 1946, Johnson and Lyon, 1991,
Figure 5.15 Larvae of viburnum borer with hardened head capsule (A), extraction of larvae Solomon, 1995). When larvae are young, newly infested plants can retain foliar turgor for
from stem (B), and an infestation causing swelling in a stem as galleries developed with weeks (Solomon, 1995). Larval feeding can yield noticeable swellings in stems. Bark may
pupa cases extending from side of stem(C) also split or flake off on smaller branches. Larval galleries beneath bark may be filled with
frass, which is a mix of moist, loose sawdust and excrement. Frass may be ejected from
when applied to host plant foliage and test on a small portion of the target crop. Refined, the gallery, thus used as a scouting sign to detect larval presence (Figure 5.15C). Both
or summer, horticultural oil treatments can be applied to control eggs, crawlers and viburnum borers are capable of completing their life cycles within a single year, and S.
immature instars on actively growing trees and shrubs. Refined horticultural oils, for fatifera can extend their development to include an entire second season when conditions
example, 2% SunSpray Ultra-Fine spray oil, can be safely used on Viburnum dentatum, V. are unfavorable (Snow et al., 1985).
opulus, V. opulus var. americanum, and V. opulus var. americanum ‘Alfredo’ to control
sap-feeding and some defoliating insects (Miller, 1997). Management
Clearwing moth pests of viburnum are unlikely to be present in large numbers in nurseries
Clearwing Borers and managed landscapes where viburnum crops and ornamental plantings are actively
Two species of clearwing moth borers (Lepidoptera: Sesiidae) are infrequent pests in the growing and healthy, and where landscape plants are mulched to prevent mechanical
eastern U.S. of both native and non-native viburnum plants. Moth species include the wounding. Pupae and eggs are seldom found while scouting nurseries and landscapes.
lesser viburnum clearwing (Synanthedon fatifera Hodges) and viburnum borer (S. viburni Differences in pupal and larval characters are generally not well determined, thus these life
Englehardt), which are widely distributed across the eastern half of the U.S. and north into stages are of limited value for distinguishing species during monitoring. When active
Canada (Solomon, 1995; Chouinard et al., 2006). Larval hosts of lesser viburnum wound sites are detected, presence of live larvae can be confirmed by direct extraction
clearwings are reported to include both American (V. opulus var. americanum) and from bark or stems (Figure 5.15B). The thin-skinned larvae are frequently destroyed
European (V. opulus) cranberry bush species (Eichlin and Duckworth, 1988; Solomon, during removal, making further identification impossible. Once actively feeding larvae are
1995). Viburnum borer larvae are reported to infest native arrowwood viburnum (V. confirmed, other infested stems can often be pruned out and discarded. Adult male
dentatum complex) and European native wayfaringtree viburnum (V. lantana; Eichlin and clearwing moths of both species can also be trapped and identified using pheromone lures
Duckworth, 1988; Solomon, 1995). paired with bucket (e.g. Multipher or Universal style) or sticky boards within delta or wing
traps.

Engelhardt (1946) reported that several parasitic wasps are effective in managing natural
populations of S. viburni larvae. For these reasons, active efforts to control clearwing
borers are seldom warranted (Solomon, 1995). Should monitoring of adult flight activity
and active infestations suggest that pesticide use may be warranted, several control options
are available (Table 5.5).

Dogwood Twig Borer
Dogwood twig borer [Oberea tripunctata (Swederus)] is a type of longhorned woodboring
beetle (Coleoptera: Cerambycidae), so named because of the long antennae visible on adult
beetles. Larvae of these adults are called roundheaded borers because they are cylindrical
in shape and chew round exit holes through the wood and bark just prior to pupation and
adult emergence. The dogwood twig borer adults are slender beetles about 0.12 inch (0.31
cm) wide and 0.4-0.6 inch (1-1.5 cm) long. Adult beetles have dark to almost black heads

142

A with the top of the reddish thorax having three Thrips
black spots that form a triangle (Figure 5.16A).
The yellow-to-tan elytra have a thin black line In the southern U.S. range for
along the middle edge and a wider black line along
the outer edge or side (Carter et al., 1980; Baker, viburnum, two thrips species can also L
1994).
become occasional pests causing

aesthetic injury to foliage. In Florida,

V. odoratissimum and V. suspensum

may be injured by redbanded thrips

While dogwood is the preferred host, dogwood (Selenothrips rubrocinctus (Giard);

twig borers also attack azalea, blueberry (Vaccinum Johnson and Lyon, 1991). The AE
common name of this thrips originates
sp.), elm (Ulmus sp.), laurel, mulberry (Morus sp.),

poplar (Populus sp.), rhododendron, sourwood, from the appearance of the cream- Bugwood
colored juveniles (only) that have a
viburnum, and willow (Salix sp.). Dogwood twig © Lyle Buss, UF

© Tam Stuart, 2007 borers can also infest fruit trees in the genera bright red band around the upper Figure 5.17 Redbanded thrips adult (A), larvae
abdomen and a red spot at the (L), and egg (E)
B Malus and Prunus (Solomon, 1995). In early to abdominal tip (Figure 5.17). Adult S.
mid-June, adult female dogwood twig borer

individuals make two encircling bands of rubrocinctus are dark brown to black

punctures about 0.5 to 1 inch (1.3-2.5 cm) apart colored and about 0.05 inches (1.2 mm) long. In Florida, south Georgia, and along the

near the branch tip. Females then make a vertical Gulf Coast, multiple generations per year can be expected (Johnson and Lyon, 1991).

slit between the rings and insert a single egg

beneath the bark flap (Solomon, 1995). After eggs Chilli thrips, (Scirtothrips dorsalis (Hood); Figure 5.18), is a non-native pest from Asia and
the Indian subcontinent (Kumar et al., 2013). This species has recently become established
hatch, larvae chew through the bark and enter the in Florida and Texas and perhaps other portions of the deep-southern U.S. It was first
detected in Florida in 1991 (Kumar et al., 2013) and its first established population was
© Frank Hale, UT branch, then begin tunneling toward the branch tip. detected in 2005 in a Florida planting of landscape roses (Ludwig and Bogran, 2007) and
has since been identified as far north as New York state (Kumar et al., 2013). Beyond
Figure 5.16 Dogwood twig borer After a short distance, larvae turn around and bore viburnum, chilli thrips commonly infest roses, schefflera (Schefflera sp.), Indian hawthorn
adult (A) and holes near branch tips down the center of the branch toward the main (Raphiolepis indica) and pittosporum (Pittosporum sp.; Ludwig and Bogran, 2007). Chilli
from dogwood twig borer larvae trunk (Solomon, 1995). Along the way, larvae cut a thrips can complete reproduction on at least 36 common annual and perennial ornamental
(B). Note frass extruded from holes line of small, closely spaced holes in the branch so plant species, yet have a food resource host plant range that includes more than 112 species
on the leaf that frass can be pushed out (Figure 5.16B). In fall, of plants in 40 different plant families (Kumar et al., 2013). Redbanded thrips also feed on
branch portions that contain larval tunnels will die avocado (Persea americana), lychee
nut (Nephelium litchi), tung (Aleurites
and larvae overwinter in the hollowed out branch sp.), acacia (Acacia sp.), persimmon
(Diospyros virginiana), sweetgum
between two plugs of frass (Solomon, 1995). In spring, mature larvae girdle the branch (Liquidambar styraciflua), Brazil
pepper tree (Schinus molle),
from the inside out, which weakens the branches leading to visible breaks in spring. pyracantha (Pyracantha sp.), as well
as many other fruit, shade and
Larvae plug the openings of broken branches with frass then pupate within small chambers ornamental trees, shrubs, and vines
(Johnson and Lyon, 1991).
during April and May. There is one generation per year in the South (Solomon, 1995).

Management Feeding injury by thrips is generally © Andrew Derksen, FDACS-DPI Bugwood
Tunneling by the larvae should cause tip die-back in the summer. Look for tip die-back concentrated on young plant foliar
and for sawdust-like frass being pushed out of the small holes in the branch by the larva. tissues and flower portions (Figure Figure 5.18 Chilli thrips adult and exuviae of
Prune several inches below where the larva is tunneling. Dispose of the branch containing second instar (arrow)
the larva (or use the specimen inside the branch as an employee teaching tool for scouting)
because the larva should continue to tunnel inside and expel the frass. Protective
insecticide applications to the bark are seldom needed for this pest. If the amount of
damage from this pest has been objectionable over the prior year, one of the insecticides
listed under wood boring beetles in Table 5.5 can be applied to the bark in the spring just
prior to when egg laying is expected in your area.

143

A 5.19A). The rasping action of feeding Natural enemies including minute pirate bugs (Orius spp.), the phytoseiid mites
thrips causes cellular damage to leaf, [Neoseiulus cucumeris Oudemans and Amblyseius swirskii (Athias-Henriot)], and
bud, and flower tissues, with plant predatory mites, Euseius spp., can also be effective predators of chilli thrips and other
portions becoming bronzy to silver in thrips species. Other pest thrips species have been managed, in part, by several predatory
color. Across time, infested tissues thrips species, lacewings (Chrysoperla spp.), ladybird beetles, and predatory mirid bugs
become stunted, contorted and brittle (Kumar et al., 2013).
with premature senescence of plant
parts commonly observed (Johnson Foliar sprays and soil drenches of neonicotinoids (IRAC class 4A) imidacloprid,
and Lyon, 1991; Ludwig and Bogran, thiamethoxam, and dinotefuran, the spinosyns (IRAC class 5) spinosad and spinetoram,
2007). Leaves of plants infested by and borax (IRAC class 8D) provided at least 10 days suppression of thrips (IRAC, 2013)
chilli thrips curl upward in response (Table 5.5). Beauveria bassiana (as Botanigard®, not IRAC encoded) extended 5 days of
larval thrips suppression. Pyrethroids (IRAC class 3) were largely ineffective for thrips
B to upper surface cellular sap removal control (Seal and Kumar 2010). A landscape study in Texas supported efficacy of acephate
(Figure 5.19B; Kumar et al., 2013). (as Orthene®) against chilli thrips (Ludwig and Bogran, 2007).
Honeydew has been noted in
association with redbanded thrips Southern Red Mite3
infestations (Johnson and Lyon 1991).

Southern red mite [Oligonichus ilicis

Degree day modeling for chilli thrips (McGregor)] is a widely distributed, cool-season

determined that a 49.5°F (9.7°C) base mite that feeds on many broad-leaved ornamental

temperature and 91°F (33°C) upper host plants in the eastern U.S . In addition to

© Lance S. Osborne, UF temperature threshold best predicted viburnum (Carter et al., 1980), susceptible hosts
development and revealed that just
include camellia, clethra, eleagnus (Eleagnus

Figure 5.19 Chilli thrips induced damage on 506°F (281°C) degree days are sp.), eucalyptus (Eucalyptus sp.), Eugenia,

sweet viburnum (A) typical feeding injury and required to complete an egg-to-egg hibiscus (Hibiscus sp.), Japanese holly and other

(B) leaves curling upward in response to heavy developmental cycle, thus multiple Ilex sp., photinia, pyracantha, laurel, © Lance S. Osborne, UF
rhododendron and azalea species (Carter et al.,
infestation annual generations will occur in the

southern U.S. (Holtz, 2006). Chilli 1980; Johnson and Lyon, 1991). Adult female Figure 5.20 Southern red mite adults,

thrips are capable of vectoring viral pathogens to plants and may be accidentally southern red mites are about 0.02 inch (0.5 mm) immatures, eggs, and cast skins

distributed in commerce. The thrips are unlikely to persist across seasons in regions of the long, rounded and reddish brown body, have no

U.S. where winter temperatures are about 25°F (-4°C) for five consecutive days (Kumar et clear division between body segments, and have four pairs of legs (Figure 5.20). In New

al., 2013). Jersey, the first peak in mite activity was observed in April (Mague and Streu, 1980).

Populations build during spring and fall and mites become quiescent, resting during hotter

Management summer temperatures. Despite this cycle, southern red mites achieve multiple generations
Thrips species are thigmotactic, having a behavioral preference for inhabiting dense plant
tissues and flower parts where they are not easily dislodged. This behavior, as well as per year.
frequency at which eggs are deposited within leaf tissues, makes detection extremely
difficult during both scouting and nursery inspections prior to shipping. When affected Management
tissues are suspected, plant portions should be collected and transported in a sealed plastic Successful mite management requires nursery growers and landscape managers to actively
bag. Examination by microscope and help of a county Extension agent or expert may be scout seasonal hot spots (e.g., dry areas, next to dusty roadways, and close to exhaust fans
needed to provide an accurate diagnosis. Sampling for thrips may be assisted by washing and doorways), and to monitor efficacy of control efforts once initial treatment is made.
affected plant portions with 70% ethanol, then scouting the screened portion of the rinsate. Remove weeds, debris, and dehisced plant material to maintain a clean environment.
Yellow sticky cards are also effective at collecting S. dorsalis, while other thrips species Increasing humidity and spraying foliage with water can limit mite development. Scout for
are preferentially attracted to blue colored cards (Kumar et al., 2013). Several classes of
insecticides are available for thrips control (Table 5.5). 3 Discussion of Southern red mite (Oligonichus ilicis) management is largely based on text prepared for
Camellia (Knox et al. 2014) (see Chapter 2, in: IPM for Shrubs in Southeastern US Nursery Production,
Part 1. 2014. White, S.A. and W.E. Klingeman, eds.).

144

mites by inspecting stippled, bronzed, or curled leaf undersides of suspect plants. Use a
10x hand lens to see adult and immature mites and eggs. If large numbers of plants are
scouted in a cropping system, foliage can be shaken above a white sheet or piece of paper.
Adult and nymphal southern red mites will appear red or pink. Commercially-available
biological agents include Phytoseiulus persimilis Athias-Henriot and Amblyseius andersoni
(Chant) predatory mites that can be deployed in individual sachets or shaken onto foliage
from bottles containing an inert carrier. In general, plant feeding mites move more slowly
than predatory mites.

Miticides available for mite control in nurseries include abamectin, acequinocyl,
bifenazate, chlorfenapyr, clofentezine, etoxazole, fenazaquin, fenbutatin-oxide,
fenpyroximate, hexythiazox, pyridaben and spiromesifen (Table 5.5). Horticultural oil,
insecticidal soaps and neem oil can also be used. These products have more limited
contact and residual efficacy than chemical pesticides and will need to be reapplied more
frequently to prevent populations from rebounding. Although broad-spectrum
chlorpyrifos, carbaryl and pyrethroids have activity against mites, these control options
may severely limit natural enemies in nursery and landscape systems, thus their use is
generally discouraged within IPM programs. These products have more limited contact
and residual efficacy than chemical pesticides and will need to be reapplied more
frequently to prevent populations from rebounding. Although broad-spectrum insecticides,
including pyrethroids, have activity against mites, these management options can severely
limit natural enemies in nursery and landscape systems, thus their use is generally
discouraged within IPM programs (Adkins et al., 2010; Frank and Sadof, 2011). For
efficient mite management, pesticide applications should be repeated at 7-14 day intervals
as directed by monitoring efforts. Thorough canopy coverage is needed for successful
management. Adding a surfactant or penetrant may increase penetration of spray solutions
into hard to reach crevices or between bud scales. If used, test a portion of the crop for
possible phytotoxicity. Because mite populations reproduce rapidly, it is critical to rotate
among different pesticide modes of action to restrict development of miticide resistance.

145

Table 5.5 Pest-directed insecticidal activity and Insecticide Resistance Action Committee (IRAC) codes for use developing an insecticide rotation plan to manage key pests of viburnum for
nursery (N) and greenhouse (G) and landscape (L) management systems. Check current products for labeled pesticides, sites for control and plant safety and efficacy on pest species. Several
products listed are available only to certified professional applicators and may not be available for homeowner useZ

IRAC Chemical Class Active Ingredient Brand NameX Nursery / Viburnum Four-lined Aphid Armored Wood- Clearwin Spider Thrips
CodeY (Mode Of Action) Greenhouse / Leaf Beetle, Plant Bug Scales boring g Moth Mites
Carbamates carbaryl Sevin SL X Beetles Borers X
1A (Acetylcholinesterase [AChE] methiocarb Mesurol 75W Landscape Japanese X X
1B inhibitors) acephate Acephate, Orthene Beetle, X X
chlorpyrifos Chlorpyrifos, Dursban 50W X X
3A Organophosphates dicrotophos Duraguard 20 ME Cranberry X X
(Acetylcholinesterase [AChE] dimethoate Inject-A-Cide B Rootworm X X
inhibitors) malathion Dimethoate 4E, 4EC X X
methadiathon Malathion 5EC N, G, L X X X X XW X
Pyrethrins and Pyrethroids oxydemeton Supracide 2E
(Sodium channel modulators) methyl Harpoon N, G X X X
trichlorfon MSR Spray Concentrate X
Dylox T&O N, G, L X X X XX X
bifenthrin Attain X XX X X
Onyx N XX X X X
cyfluthrin Onyx Pro X X X X
Talstar N, G X X X X X X
lambda-cyhalothrin Decathlon X X X X
cypermethrin Tempo L XX X X X
deltamethrin Scimitar CS X X X X
fenpropathrin Scimitar GC NX X X X
tau-fluvalinate Demon X X
DeltaGard T&O 5EC, L XX X XX X
Granular X XX X
Tame N X XX
Mavrik Aquaflow
LX X

N

LX

N, G X X XX
XX
L XX XX
X
N, L X X X
X
N, G, L X X X
X
N, G X X X

L XX X

L XX X X
X
N, G, L X X X

L XX X

L XX X

N, G X X
N, G, L X X

146

Table 5.5 continued Pest-directed insecticidal activity and IRAC codes for use developing an insecticide rotation plan to manage key pests of viburnum

IRAC Chemical Class Active Ingredient Brand NameX Nursery / Viburnum Four-lined Aphid Armored Wood- Clearwin Spider Thrips
CodeY (Mode Of Action) Greenhouse / Leaf Beetle, Plant Bug Scales boring g Moth Mites
X X Beetles Borers X
Landscape Japanese X X X
Beetle, X X X X
X X X X
Cranberry X X X X
Rootworm X X X
X X X X
Astro G, L X X X X X X X
X X X X X
3A Pyrethrins and Pyrethroids permethrin Permethrin Pro L XX X X X X
(Sodium channel modulators) Perm-Up N XX X X X
X X X X
Pyrethrum TR N, G XX X X X X
X X
cyfluthrin + Discus N/G N, G XX X X X
imidacloprid X
X X
lambda-cyhalothrin Tandem L XX X X
+ thiamethoxam
Pyrethrins and Pyrethroids + X
3A + 4A Neonicotinoids X

bifenthrin + Aloft LC SC, LC G L XX X
clothianidin X

bifenthrin + Allectus SC L XX
imidacloprid

acetamiprid Tristar 30SG, TriStar 8.5 SL N, G, L XX

clothianidin Arena L

dinotefuran Safari N, G, L X
Zylam SL L XX
Neonicotinoids
4A (Acetylcholine receptor [nAChR] Merit LX

agonists) imidacloprid Marathon N, G X

CoreTect LX

Meridian L XX
Flagship
thiamethoxam Conserve SC N, G XX
spinosad Entrust
Spinosins abamectin Avid 0.15 EC N, G, L XV
5 (Nicotinic acetylcholine receptor
N, G, L XV
channel [nAChR] agonists)

N, G, L XU X
X
6 Avermectins emamectin Tree-äge L X
(Chloride channel activators) benzoate X

milbemectin Ultiflora N

7A Juvenile hormone analogues s-kinoprene Enstar AQ G X
(Juvenile hormone mimics)

147

Table 5.5 continued Pest-directed insecticidal activity and IRAC codes for use developing an insecticide rotation plan to manage key pests of viburnum

IRAC Chemical Class Active Ingredient Brand NameX Nursery / Viburnum Four-lined Aphid Armored Wood- Clearwin Spider Thrips
CodeY (Mode Of Action) Greenhouse / Leaf Beetle, Plant Bug Scales boring g Moth Mites X
Preclude X Beetles Borers XT
7B Distance Landscape Japanese X X
7C Beetle,
8D X
9B Cranberry
9C Rootworm X
10A
10B Juvenile hormone analogues fenoxycarb G X X 148
12B (Juvenile hormone mimics) pyriproxifen X
sodium N, G, L
13 Miscellaneous, non-specific tetraborohydrate
inhibitors (Multi-site action) Decahydrate Prev-AM Ultra N, G XX X
15 pymetrozine
16 Compounds of non-specific mode of flonicamid Endeavor N, G, L X
action clofentazine Aria G X XX
20B hexythiazox Ovation SC N, G
Mite growth inhibitors Hexygon DF N, G, L X
21A etoxazole Beethoven TR G X
TetraSan 5 WDG N, G, L X
22A X
Organotin miticides fenbutatin-oxide ProMITE 50WP N, G, L X
(Inhibits mitochondrial ATP chlorfenapyr
synthesis) novaluron Pylon G X
buprofezin
Chlorfenapyr Pedestal N, G X X
(Uncouples oxidative X XX
phosphorylation via disruption of H Talus 70DF N, G, L
proton gradient) X XX
Shuttle O N, G X
Benzoylureas Miticide L
(Inhibitors of chitin biosynthesis, Shuttle 15 SC N, G, L
type 0; insect growth regulator) Magus Miticide N, G
Akari 5SC N, G
Buprofezin Sanmite G
(Inhibitors of chitin biosynthesis, Hachi-Hachi L
type I; insect growth regulator)
Provaunt
(Mitochondrial complex III electron acequinocyl X
transport inhibitors)
X
METI acaricides fenazaquin X
(Mitochondrial complex I electron fenpyroximate X
transport inhibitors) pyridaben X
tolfenpyrad
(Voltage-dependent sodium channel
blockers) indoxacarb

Table 5.5 continued Pest-directed insecticidal activity and IRAC codes for use developing an insecticide rotation plan to manage key pests of viburnum

IRAC Chemical Class Active Ingredient Brand NameX Nursery / Viburnum Four-lined Aphid Armored Wood- Clearwin Spider Thrips
CodeY (Mode Of Action) Greenhouse / Leaf Beetle, Plant Bug X Scales boring g Moth Mites X
Beetles Borers
Landscape Japanese X
Beetle, X

Cranberry
Rootworm

Tetronic and tetramic acid Judo N, G
derivatives (Inhibitors of Forbid 4F
23 acetyl CoA carboxylase) spiromesifen Kontos L
25 Beta-ketonitrile derivatives
28 (Mitochondrial complex II spirotetramat Sultan N, G X X
Unknown electron transport inhibitors)
Diamides (Ryanodine receptor cyflumetofen Acelepryn GX
Not modulators) Azatin XL, Aztrol
Required chlorantraniliprole Floramite SC L X X
Mode of action unknown azadirachtin Overture XX
bifenazate BotaniGard 22WP, ES N, G, L X
IRAC code not required pyridaryl Preferal N, G, L X XX X
Beauveria bassiana G XX X
Isarea formosarosea Met52, Tick-EX N, G, L XX
Metarizium N, G, L X XX XX
anisopliae Ultra-Fine Oil X XX
horticultural oil M-Pede N, G, L X
insecticidal soap Triple Action Neem Oil XX
Trilogy N, G, L X XX
neem oil Triact 70 N, G, L X XX XX
L X
N, L X
N, G, L X

Z Check labels carefully to determine if any ornamental phytotoxicity has been reported. It is always sound management practice to test for pesticide safety to plants on a small portion of ornamental plants before spraying the
entire nursery crop or range

Y Insecticide Resistance Action Committee (IRAC) 2014 database
X Trade names of products are provided as examples only. No endorsement of mentioned product nor criticism of unmentioned products is intended
W Locust borer (a roundhead borer) is listed on label
V Not labeled for Japanese beetle adults. Cranberry rootworm and viburnum leaf beetles (Chrysomelidae) are leaf feeding beetles that are listed on the label
U Lyriomyza leafminers are listed on label
T Pest management primarily by population suppression, rather than direct mortality, demonstrated when sodium tetraborate plus orange oil and biodegradable surfactants [as TriCon™, BioWorks, Inc. (no longer commercially

available)] was applied as foliar spray (Seal and Kumar 2010)

149

SECTION 4 Most viburnum species and cultivars are considered to be "trouble-free" and generally
support very few pests and plant diseases that cause significant or lasting aesthetic injury
Disease Management (Dirr, 2007; Johnson and Lyon, 1991). Despite the pest tolerance and durability of
viburnums, diverse pests and plant diseases are capable of causing injury in the
© Oregon Department of Agriculture southeastern U.S. Labeled fungicidal active ingredients, modes of activity and related
Fungicide Resistance Action Committee (FRAC, 2013) codes will help managers integrate
Phyotophthora ramorum leaf blight on Viburnum plicatum var tomentosum plant disease control within a pesticide rotation plan for viburnum (Table 5.8 - end of
'Mariesii' section 4).

COMMON DISEASE PESTS Phytophthora Root Rot
Root rot causing Phytophthora spp. include several species of water mold pathogens, or
1. Phytophthora Root Rot 8. Powdery Mildew oomycetes. They can become problematic in container production and are most difficult to
2. Phytophthora Leaf Blight 9. Botryosphaeria Canker manage in warm, wet soils and container substrates. The soil-borne pathogens initially
3. Downy Mildew 10. Cytospora Canker infect small feeder roots and then spread to main roots of viburnum and many other host
4. Fungal Leaf Spots 11. Foliar Nematodes plants. Plant crowns may be invaded if conditions remain conducive for spread. Above-
5. Anthracnose Diseases ground symptoms, which include yellowing of leaves, sudden wilting, premature leaf drop,
slowed shoot growth, branch dieback, and plant death, are the most visible indicators of
contamination and are usually the first problem reported (Benson and von Broembsen,
2001).

Water molds such as Phytophthora spp. require free water to survive and reproduce.
Spores have long whip-like structures, or flagella, that assist them to swim. In turn, spores
are easily and quickly spread by contaminated water in nurseries, particularly where
irrigation water runs through rows and production areas. Wet soils and saturated substrates
provide a medium for pathogens to move into root zones. Once established, these
pathogens produce overwintering structures, or chlamydospores, that can survive in a
variety of climate extremes (Agrios, 1997). When environmental conditions reach optimal
levels between 68 to 90°F (20 to 32°C), accompanied by saturated soils, the pathogen
breaks out of dormancy and infects susceptible plants (Benson and von Broembsen, 2001).

Management
Proper irrigation management and preventative and timely fungicide applications are
important in management of Phytophthora root rot in container-grown viburnum. Avoid
conditions that allow water to puddle around containers. Sheet flow of nursery irrigation
runoff can be restricted from pooling around container bottoms by adding 2 to 3 inches (5.2
to 7.6 cm) of gravel beneath containers. Thoroughly wash and disinfest recycled
containers before use. Fungicides that are most effective against water molds include
cyazofamid, mefenoxam, and phosphorus acids. Dimethomorph, fluopicolide, and
etridiazole also have some activity against the Phytophthora root rot pathogens (Table 5.8).

Phytophthora Leaf Blight
Disease symptoms of Phytophthora leaf blight, also known as sudden oak death, are
caused by Phytophthora ramorum Werres, De Cock & Man in’t Veld. Visible disease
symptoms in host plants, including viburnum, appear as shoot blight, or rapid shoot death

150

with dropping foliage, resulting in leafless A Downy Mildew
shoots, to leaf blight evidenced by rapid foliar The downy mildew pathogen
discoloration (Figure 5.21). Young leaves and © C. Blomquist, CA Dept. Food & Ag © FL Dept of Plant Industry Bugwood (Plasmopara viburni Peck) prefers cool,
shoots are most susceptible to P. ramorum B humid or wet conditions; thus, symptom
infection. Often, roots look healthy, even when development is often most common
they are infected. Spores, also called sporangia, during spring and fall. Symptoms begin
may also move through wind-driven rain or as light green to yellow spots on upper
water splash during rains or overhead irrigation. sides of leaves. As leaf wetness persists,
Humans and equipment can also move the spots or blotches become large, reddish
pathogen under shoes, tires, or other equipment. brown, and irregular, sometimes with a
Long distance movement occurs though yellow halo, delimited by leaf veins
movement of infected plant material (Oregon (Figure 5.22A). White cottony fungal
Department of Agriculture, 2014; Dailey et al., growth is often visible on undersides of
2004). Phytophthora leaf and shoot blight leaves (Figure 5.22B). Spots coalesce,
ultimately leads to plant death (Sinclair, 2005). causing rapid leaf necrosis. Leaves
usually become bronze-colored, curl up
Phytophthora ramorum is a quarantined plant and drop (Sinclair, 2005). Often leaf drop
is the first noticeable symptom. Stressed
pathogen under APHIS regulations. Permits plants are more susceptible to infections.
Plasmopara spp., like Phytophthora
may be required when importing susceptible pathogens described above, are also
oomycete water molds that require free
species from areas known to have active disease Bugwood water to survive and reproduce. Their
spores also have long whip-like flagella
pressure. When plants are purchased from © Sandra Jensen, Cornell U. that assist in their swimming movement.
Wet foliage provides a medium for spread
quarantined regions, it is a sound management Figure 5.22 Symptoms of infection (A) by and infection.
downy mildew on Viburnum suspensum leaf
practice to keep imported plants separated from surface and underside, and (B) the white
downy growth of downy mildew on the
other plants for at least 3 to 6 months. During underside of a viburnum leaf

this time, monitor for symptom development,

recognizing that onset may become delayed if

weather conditions are hot and dry or if Figure 5.21 Phytophthora leaf blight

fungicides have been used. Contact regulatory induced by P. ramorum on Viburnum

authorities if infection is suspected. Because tinus stems (A) and leaves (B) Management
Sanitation is a critical step in downy mildew management. Rake and destroy fallen
growing space is at a premium and quarantined infected leaves to prevent spores from splashing onto healthy foliage during rain or
overhead irrigation (Rane, 2001). Preventative fungicides like azoxystrobin, cyazofamid,
areas are sometimes difficult to manage separately from production areas, consider etridiazole, fenahexamid and phosphorus acids (Table 5.8) should be used if downy mildew
is a recurring problem and at first signs of disease on viburnum.
surrounding the newly imported plants with non-susceptible host plants. This will allow

quarantined plants to be managed for growth similarly to other plants.

Management Fungal Leaf Spots
Fungicides suppress but do not cure Phytophthora leaf and shoot blights. Healthy plants There are several fungi that cause leaf spot diseases on viburnum, including Cercospora,
should be protected with fungicides mefenoxam, cyazofamid, dimethomorph, or Septoria, Ascochyta, Phoma, and Phyllosticta spp. (Sinclair, 2005). Plant damage is often
fenamidone, particularly when confirmed infections are reported nearby (Table 5.8; minimal, but unsightly appearance may restrict retail sales. Prolonged periods of leaf
Tjosvold et al., 2008). Fungicide applications have the ability to mask disease, thus once wetness and high humidity tend to favor infection, sporulation, and symptom development
routine applications cease, symptoms may resume and again become noticeable (Dailey, of leaf spots. Leaf spot diseases are most serious when overhead irrigation is used or
2004). Cuttings should be propagated only from plants that are known to be pathogen-free. during extended periods of rain (Sinclair, 1997).
Take steps to employ sanitary standards and precautions when moving susceptible nursery
plants, and walking or driving through areas with susceptible species or suspected
symptoms (Dailey, 2004).

151

Management disease, fungal mycelia masses and spores are produced primarily on upper leaf surfaces
Fungal leaf spot management relies on reducing leaf wetness by avoiding overhead during summer and fall. Mycelia and spores are occasionally found on lower surfaces.
irrigation within nurseries and possibly increasing plant spacing and branch spacing within These spores are readily wind-dispersed and do not require free water for infection
individual plants to improve air circulation. Fungicides applications, if used, should be (Benson, 2001). Thus, new infections are perpetuated throughout the season. In late
applied preventatively to reduce disease development and spread. However, they are often summer, the fungus produces scattered black fruiting structures, called cleistothecia, on
not needed to manage leaf spot diseases on viburnum. undersides of leaves (Benson, 2001). These structures are easily disseminated by wind and
also serve as overwintering structures. If the fungus invades buds in late fall, new spring
Anthracnose Diseases growth may be stunted or distorted (Rane, 2001). Powdery mildew seldom kills plants, but
Anthracnose disease symptoms can be caused by several different pathogens, including crop growth can be impaired during extreme infections (Agrios, 1997). Powdery mildew
Elsinoe, Discula, Gloeosporium, and Sphaceloma spp. fungi. Anthracnose is most fungi are host specific, so for example, a nearby diseased hydrangea is not a threat to
prevalent when overhead irrigation is used or during extended, cool rainy conditions viburnum, and an infected viburnum is not a risk to rose.
(Sinclair, 2005). Plant damage is often minimal, but unsightly appearance may negatively
influence retail sales. Each of these pathogens can cause leaf blight or large black, Management
sometimes sunken lesions that develop blotchy patches, as opposed to spots. Symptoms If nursery stock has a history of powdery mildew infection, apply azoxystrobin, fenarimol,
may appear as either angular, elongated, or round lesions that will eventually coalesce, propiconazole, thiophanate-methyl, or triadimefon fungicides during late spring and
leaving large portions of dead leaf tissue (Agrios, 1997). Anthracnose lesions quickly turn continue at 1 to 3 week intervals through summer (Table 5.8). Do not use sulfur, as most
brown or black, causing rapid blighting of leaves. Fungi overwinter on dead and fallen Viburnum spp. are sensitive to sulfur fungicides (Rane, 2001). Already discolored leaves
twigs and leaves (Agrios, 1997). will not return to a green coloration, even after the fungus is killed. Prune, rake and
destroy infected plant tissue to reduce inoculum load. Improve air movement through
Management pruning and plant spacing. Reduce excessive nitrogen and irrigation, which promote
Fungicides are only recommended as preventatives when leaf blighting becomes succulent growth that encourages powdery mildew. Viburnum cultivars resistant or
aesthetically intolerable or jeopardizes sales-timing. Avoid overhead irrigation and tolerant to powdery mildew infections include V. xburkwoodii ‘Mohawk’ and V.
splashing water to limit infection potential. If necessary, mancozeb, chlorothalonil, or xcarlcephalum ‘Cayuga’ (Rane, 2001).
thiophanate methyl can be applied when conditions are conducive for disease (Table 5.8).

Powdery Mildew © M. Grabowski, UMN Botryosphaeria Canker
Powdery mildew disease in Botryosphaeria, or Bot canker, caused by Botryosphaeria dothidea (Moug. ex Fr.) Ces. &
viburnum is caused by the Figure 5.23 Round black cleistothecia within white
fungus Microsphaera powdery mildew spots on viburnum De Not., is a common disease of
penicillata (Wallr. Lev.) and is viburnum in the southeastern U.S.
distinctive when the white, Plants under drought stress, as
powdery fungal masses appear well as those with mechanical
on upper leaf surfaces (Figure injuries, unhealed pruning cuts,
5.23). New plant growth, and affected by other
including buds and shoots, is environmental stressors are more
most susceptible. Infection is likely to become infected.
typically initiated in spring and Healthy plants are more resistant
symptoms do not appear until to infections, in part because they
early summer. Powdery mildew are more capable of wound
pathogen prefers cool, dry responses that help isolate fungal-
shade, so disease may be infected cells, thus preventing
prevalent in nursery situations further spread (Sinclair, 2005).
with poor air circulation. When © E.A. Bush, VT
conditions are conducive for
Figure 5.24 A branch with the bark partially removed Bot fungi kill cambium and
to reveal the brown discoloration in the wood caused sapwood, causing cankers. Small
by Botryosphaeria species cankers appear as dark areas of

152

discolored bark, followed by coalescing lesions that can expand to girdle branches (Figure killed bark. Likewise, black fruiting structures called perithecia may appear in newly
5.24). Water movement within the plant vascular system is stopped, leading to rapid killed wood during spring and early summer (Sinclair, 2005). Spores will be exuded from
wilting and browning of foliage (Sinclair, 2005). Disease symptoms may also include these structures during rainfall and following irrigation. Infection can occur throughout the
branch dieback, or flagging during summer months, during which small branches may die year, especially during periods of rainfall and high humidity.
and leaves suddenly turn brown. Upon closer examination, lesions on young branches
appear as bark splits that lead to formation of dark sunken cankers. On more mature limbs, Management
cankers may be partly delimited by callus tissue. Fungicides are not effective for control of Cytospora canker, and there is no cure for
infected plants. In general, viburnum health can be optimized and canker disease potential
Cankers are the sole source of fungal inoculum (Sinclair, 2005). During wet weather, fungi limited by mitigating plant stress. Provide good drainage to root systems and ensure that
sporulate from diseased cankers on branches and twigs. Spores can be produced in young plants are watered during periods of drought. Use of cold-hardy species will reduce
cankers throughout the year and can be dispersed by splashing rain or irrigation water. likelihood of winter damage to viburnum, thus reducing bark injury and potential entry
Older cankers produce dark fruiting structures, as well as a different type of spore that can sites for canker pathogens. Branches with cankers should be removed as soon as possible,
overwinter in cankers and dead bark. In spring, these overwintering structures germinate cutting at least 6 to 8 inches (15 to 20 cm) below the canker. Avoid pruning during wet
to initiate a new disease cycle. Once spores germinate, fungal hyphae can survive as weather during which spores are most easily disseminated. Make clean, sharp pruning cuts
saprophytes on bark, obtaining nutrients from dead and dying matter. It is unknown how that will heal more quickly. Spring is also a good time to prune because of the rapid
long the fungus can maintain this state before infecting plant tissue. Trees weakened by wound healing response. Disinfest tools between cuts with 10% bleach or a commercial
drought or other stresses, as well as those wounded by freeze or pruning cuts, are often sanitizer. Apply fungicides to pruning cuts if disease has been a problem in the nursery.
infected and parasitized by B. dothidea. Lenticels, or growth cracks can also serve as Destroy all diseased branches after removing them to an off-nursery location.
points of entry (Sinclair, 2005).
Foliar Nematodes
Management Foliar nematodes, primarily Aphelenchoides fragariae (Ritzema Bos) Christie in
Support plant vigor and avoid environmental stress to maintain optimal crop health, for ornamental plants, are microscopic parasitic roundworms. They feed on mesophyll cells of
example by watering during periods of insufficient rainfall. No chemical treatments are leaves and buds causing eventual cell death. Symptoms begin as yellowish to light purple
available to control bot canker. Fungicides such as liquid copper may be applied as blotches that are restricted by major leaf veins. On viburnum, the lesions are geometric,
protectants, although fungicides are usually not recommended. For best control, eliminate contained within individual venation sections in the leaf (Figure 5.25). As nematode
sources of inoculum by removing diseased and infected stems and branches. Prune at least
6 to 8 inches below visible cankers back to green healthy wood and destroy infected plant © Jean Williams Woodward, UGA
parts. These tissues should not be composted. Sanitize pruners between cuts using 10%
bleach, Lysol industrial strength disinfectant, or another commercial sanitizer. Use sharp Figure 5.25 Aphelenchoides fragariae nematode infection
pruners to encourage rapid healing. Pruning wounds may be protected with thiophanate in foliage of Viburnum ‘Spring Bouquet.’ Typical symptoms
methyl. of chlorotic to light purple blotches restricted by venation

Cytospora Canker
Cytospora cankers, including valsa canker, are typically associated with dieback of
scattered branches throughout the canopy. Stressed and unhealthy shrubs are most
susceptible to valsa canker. Fungi enter plants through injured bark, including unhealed
pruning cuts, injury caused by freeze-damage, and branch crotches. Once infection occurs,
fungi spread rapidly though healthy tissue (Sinclair, 2005). Symptoms often follow
drought, causing leaf yellowing and wilting, and eventual leaf browning. Wilted leaves
remain attached to limbs. Branches die back to their point of union with a larger limb.
Cankers are often difficult to detect on viburnum when canopies are intact and because
lesions are not always apparent by simply viewing outside bark. When suspect tissues are
dissected, a dark green line will separate healthy from diseased wood (Sinclair, 20005).
White fruiting bodies, or pycnidia, may be visible in newly formed cankers and recently

153

population increases within the affected area, the lesions darken. New lesions develop
when nematodes migrates out of stomata when free moisture is present on the leaves.
Nematodes move within the water film and into stomata in new areas (Wallace, 1959).
When the nematodes are outside of the leaf tissue, they can be water-splashed to new
leaves and adjacent plants. One of the diagnostic characteristics of foliar nematode
infestation is the gradation in color of the lesions from lightly- to darkly-colored. This
distinguishes it from Pseudocercospora leaf spot disease as all lesions developing from
fungal infection will be of the same color. Nematode infestation will cause leaves to drop
and may affect leaf and flower bud development.

Management
Management of foliar nematodes is difficult as systemic nematicides are either no longer
manufactured or are not labeled for use on ornamental plants. Management relies on
exclusion and sanitation. The nematode is primarily spread to new areas via the transport
and propagation of infested plants. Do not propagate from infested plants. Severely
affected plants should be removed and destroyed. Foliar nematodes are also capable of
undergoing anhydrobiosis, surviving extensive periods within dried leaf tissue. Removal
of leaf litter from production areas and containers is essential in reducing nematode
survival. Nematodes will also survive within dormant buds and as periodic soil
inhabitants. Since foliar nematodes are primarily within infested leaves, pruning plants to
remove symptomatic foliage can reduce nematode populations and spread. Reducing leaf
wetness duration can also help reduce nematode spread.

154

Table 5.8 Fungicidal activity arranged by Fungicide Resistance Action Committee (FRAC) codes to facilitate development of a fungicide rotation plan for managing key plant pathogens of
viburnum. Check current products for labeled pesticides, sites for control and plant safety and efficacy on fungal speciesZ. Within columns, products indicated by “X” are labeled for use
against the listed pathogen type. Several listed active ingredients are available only to certified professional applicators and may not be available for homeowner use (check for more current
guidelines in regularly up-dated resources, e.g., Ward 2014). Site conditions, phytotoxicity information and available formulations are also subject to annual revision therefore
recommendations from this table should be validated by consulting the most current product labels

FRAC Class Description Active Ingredient(s) Brand Names Leaf Powdery Stem/Root Leaf Downy Action and Management Notes
Code Spots Mildew Rots by Blight Mildew
fungal
fungal Water Molds oomycetes oomycetes
X
X oomycetes

1 BenzimidazolesY thiophanate-methyl Cleary's 3336TM X X Upwardly systemic. Broad spectrum fungicide for various
AllBan® X fungi. Fungicide resistance risk high. Tank mix with
thiophanate-methyl Banrot® 400* X fungicides from a different fungicide group (FRAC) to
X prevent or delay resistance development. Do not mix with
etridiazole + thiophanate- Zyban®* X copper.
methyl X X
X X
thiophanate-methyl + X
mancozeb X

2 Dicarboximides iprodione Chipco® 26019** X Locally systemic, long protection period during wet
X conditions. Broad spectrum fungicide for greenhouse and
X nursery use. Medium to high risk for resistance. Toxic to
X honey bees; do not apply during bloom.
X
propiconazale Banner® MAXX® II X
Bayleton®
triadimefon Eagle® 20 X Upwardly systemic with some curative activity. Rainfast in 2
Sterol biosynthesis Funginex®
3 inhibitors (DMI, SBI, or myclobutanil Strike® 50 WDG** X hours. There is wide variation in activity within this group.
SI) Effective on powdery mildew, but not effective on downy

triflorine X mildew. Medium risk for resistance.

triadimefon X

4 Phenylamides mefenoxam Subdue® Systemic. Effective against diseases caused by oomycetes
MAXX®** X X X (water molds), including damping-off, root and stem rots, and

foliar diseases. Use as soil drench or foliar application.

Succinate pyraclostrobin + boscalid Pageant®* XX Upwardly systemic fungicide with varying degrees of
7 dehydrogenase X systemic activity. Effective on mildews, foliar pathogens, and

inhibitors (SDHI) most fungi. Medium to high risk for resistance.

azoxystrobin Heritage® XX X Locally systemic. Effective on mildews, foliar pathogens,
pyraclostrobin + boscalid Pageant®* XX
11 Quinone outside trifloxystrobin Compass®** XX X and most fungi. Some control of oomycetes (water molds).
inhibitors (QoI) Fungicide resistance risk high. Note: These fungicides are

X also known as strobilurins.

12 Phenylpyrroles fludioxonil Medallion® Non-systemic but good residual protection. Broad spectrum
fungicide, not effective against oomycetes (water molds).

155

Table 5.8 continued Fungicidal activity arranged by FRAC codes to facilitate development of a fungicide rotation plan for managing key plant pathogens of viburnum.

FRAC Class Description Active Ingredient(s) Brand Names Leaf Powdery Stem/Root Leaf Downy Action and Management Notes
Code Spots Mildew Rots by Blight Mildew

fungal fungal Water Molds oomycetes oomycetes

oomycetes

etridiazole Terrazole® X

etridiazole Truban® X X X Locally systemic. Effective against water molds (oomycetes).
14 Aromatic hydrocarbons triflumizole Terraguard®** X Some products in this group may not be used in residential
landscapes, playgrounds, athletic fields, or golf courses
etridiazole + Banrot®400*
thiophanate-methyl

17 Hydroxyanilides fenahexamid Decree®** XX Locally systemic. For use in outdoor and greenhouse nursery
crops

21 Quinone inside inhibitors cyazofamid Segway® X X X Locally systemic. Effective against water molds (oomycetes).
Resistance risk unknown but presumed to be medium to high

28 Carbamates propamocarb Banol®* X Locally systemic. Control of oomycetes (water molds). Not for
use in landscapes

phosphorus acid AludeTM X Fully systemic; when applied to leaves, product can translocate to
fosetyl-AL Aliette®
33 Phosphonates phosphorus acid Vital® X lower parts. Effective against water molds (oomycetes) such as
Phytophthora, Pythium, and downy mildew pathogens. Low risk

X for fungicide resistance development

mandipropamid MicoraTM X X X Locally systemic. Control of oomycetes (water molds). Not for
40 Carboxylic acid amides Stature® SC X X X use in landscapes

dimethomorph

copper Kocide® 2000 X

copper Champ® WG X

M Multi-site inhibitors captan Captan X X No systemic activity. Effective as protectants on broad spectrum
chlorothalonil Daconil X X including most fungi and mildews. Fungicide resistance risk low
chlorothalonil Manicure® 6FL X

mancozeb Dithane® X

ziram Ziram® 76DF X

NC Not a classified sodium tetraborate Prev-AM® X X Contact activity with labeled uses on outdoor nursery and
substance Ultra greenhouse crops. Fungicide resistance risk low

Z This table reports information on fungicide labels and does not necessarily reflect product efficacy. Refer to fungicide labels for rates and usage, specific host information, possible phytotoxicity, re-entry intervals and
resistance management

Y This group was formerly known as De-Methylation Inhibitors (DMI) and are now classified as Sterol Biosynthesis Inhibitors (SBI or SI)
* Chemical contains more than one active ingredient, thus more than one FRAC code is assigned
** Not for use in residential landscapes. Commercial use only. See label
This table reports information on fungicide labels and does not necessarily reflect product efficacy

156

SECTION 5

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