Landscape Message: July 14, 2023

UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Massachusetts Green Industry professionals in the management of our collective landscape. Detailed reports from scouts and Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. The following issue has been updated to provide timely management information and the latest regional news and environmental data.

Thanks for your continuing interest!  Note that we are now in the every other week period of the season, and the next message will be posted on July 28.  To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list 

To read individual sections of the message, click on the section headings below to expand the content:

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Scouting Information by Region

Environmental Data

The following data was collected on or about July 12, 2023. Total accumulated growing degree days (GDD) represent the heating units above a 50ºF baseline temperature collected via regional NEWA stations (http://newa.cornell.edu) for the 2023 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

MA Region/Location	2023 Growing Degree Days		Soil Temp (°F at 4" depth)		Precipitation (Gain in inches since last report)	Time/Date of Readings
	Gain since last report	2023 total	Sun	Shade
CAPE	334	988	77	72	2.11	7/12/2023 12:00 PM
SOUTHEAST	353	1008	83	72	2.55	7/12/2023 2:30 PM
NORTH SHORE	311	932	71	67	2.41	7/12/2023 10:00 PM
EAST	346	1121	79	72	1.94	7/12/2023 4:00 PM
METRO	334	1037	71	66	3.04	7/12/2023 5:15 AM
CENTRAL	335	1094	75	67	7.74	7/12/2023 8:30 AM
PIONEER VALLEY	350	1146	76	71	5.87	7/12/2023 12:00 PM
BERKSHIRES	306	926	73	67	3.47	7/12/2023 5:30 PM
AVERAGE	334	1032	76	69	3.64	-
n/a = information not available

 

US Drought Monitor:  Recent rains have wiped out previous drought areas, and then some in many locations, as evidenced by recent flooding.  State map as of Thursday 7/13: https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?MA

Phenology

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT NAME (Botanic / Common)	CAPE	S.E.	N.S.	EAST	METRO W.	CENT.	P.V.	BERK.
Hibiscus syriacus (rose-of-Sharon)	*	Begin	*	*	*	Begin	Begin	*
Buddleia davidii (butterfly bush)	Begin	*	*	*	Begin	*	Begin	*
Lythrum salicaria (loosestrife)	Begin/Full	Full	*	*	*	*	*	*
Campsis radicans (trumpet vine)	Begin/Full	Full	Full	Full	Full	*	Full	Begin
Hydrangea paniculata (panicle hydrangea)	Begin	Full	Full	Begin	Full	Full	Full	Begin/Full
Koelreuteria paniculata (goldenrain tree)	Begin/Full	Begin/Full	Begin/Full	Begin	*	*	Full/End	*
Hydrangea macrophylla (bigleaf hydrangea)	Begin/Full	Full	Full	Full	Full	Full	Full	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions:

The average temperature for the period from June 28 thru July 12 was 72ºF with a high of 87ºF on July 11 and a low of 62ºF on July 1. Daytime highs have primarily been in the upper 70s and low 80s with nighttime lows in the upper 60s. The dewpoint has been high for much of the period, making it sticky and uncomfortable. 

Precipitation fell on several days, the majority coming in showers on June 28, July 3, and July 4, totalling just over 2 inches. Soil moisture is adequate. Soil moisture was short/dry up until about mid-June and since that time precipitation, mainly from showers, has outpaced evapotranspiration rates. In unirrigated landscapes, the response to increased soil moisture has been visible in vegetative growth. In irrigated landscapes, local precipitation amounts should be monitored to avoid needless irrigation.

Herbaceous plants seen in bloom during the period include daylily (Hemerocallis spp.), hosta (Hosta spp.), purple cone flower (Echinacea purpurea), shasta daisy (Leucanthemum x superbum), and astilbe (Astilbe japonica). Woody plants seen in bloom include privet (Ligustrum spp.), elderberry (Sambucus canadensis), Japanese spirea (Spiraea japonica), New Jersey tea (Ceanothus americanus), with summersweet (Clethra alnifolia) and sourwood (Oxydendron arboreum) just starting to bloom. 

Pests/Problems:

Insects or insect damage observed during the period include hibiscus sawfly larvae feeding on hardy hibiscus, spittlebugs on oak, earwigs, and Japanese, Asiatic and Oriental beetles on various plants.

Disease symptoms or signs observed this period include beech leaf disease on American beech, apple scab on crabapple, cedar-apple rust on crabapple, Venturia leaf and shoot blight on poplar, pear trellis rust on callery pear, guignardia leaf blotch on horsechestnut, leaf spot on river birch, maple anthracnose on red maple, oak anthracnose on white oak, powdery mildew on phlox and lilac. 

Weeds in bloom include Japanese honeysuckle (Lonicera japonica), cats ear (Hypochaeris radicata), white clover (Trifolium repens), fleabane (Erigeron annuus), sheep’s bit (Jasione montana), birdfoot trefoil (Lotus corniculatus), Pennsylvania smartweed (Polygonum pennsylvanicum), and knapweed (Centaurea maculosa).

Slugs, snails, and rabbits have also been observed damaging plants.

Southeast Region (Dighton)

General Conditions:

Hazy, hot, and humid are the bywords for the past two weeks. We started well enough with a daytime high of 76°F on Thursday, June 29th but temperatures trended gradually higher before reaching 90°F by midday on Wednesday, July 12th. The low temperature for the two weeks was 56°F on the morning of Saturday, July 1st. The average was 72°F. There were rain storms on Monday, July 3rd, Wednesday, July 5th, and Monday evening through Tuesday, July 12th for a total of 2.55 inches overall. The high wind speed was 20 mph on Sunday, July 2nd.

Plants currently in flower: Campsis radicans (trumpet vine), Hibiscus syriacus (rose-of-Sharon), Hydrangea macrophylla (French/bigleaf hydrangea), H. paniculata (panicled hydrangea), Koelreuteria paniculata (goldenrain tree), Lythrum salicaria (purple loosestrife), Reynoutria japonica (Japanese knotweed)

Monarch butterflies have arrived. Hummingbird moths and Eastern tiger swallowtail butterflies are also present. 

Pests/Problems

Rust and black spot on rose. Earwig damage. Snail and slug damage. Crabgrass is making great progress with high temperatures and plentiful moisture. Their tillers are expanding rapidly and rooting in, making it quite challenging to hand weed them. High temperatures and humidity have made for dangerous conditions outdoors, especially for children and elders. Warnings for flash flooding and lightning strikes have been issued during the passing storms. On the plus side, the NOAA drought monitor as of July 6th shows normal soil moisture in both Plymouth and Bristol Counties.

North Shore (Beverly)

General Conditions:

The first half of this reporting period was very pleasant with day temperatures in the low to mid 70s. In the second half of the reporting period, we experienced real summer weather. It was hot and humid with day temperatures in the low to high 80s. Although it was hot during the day, nighttime temperatures were in the low to mid-60s most of the days during this period. A few storms passed through the area and brought significant amounts of rainfall. Approximately 2.41 inches of rainfall was received at Long Hill in Beverly. Because of the rains and warm temperatures, turf on lawns is growing fast and requires regular mowing. Woody plants seen in bloom include: oakleaf hydrangea (Hydrangea quercifolia), bigleaf hydrangea (Hydrangea macrophylla), tree false spirea (Sorbaria arborea), cut-leaf chaste tree (Vitex negundo), Golden rain tree (Koelreuteria paniculata), Japanese hydrangea vine (Schizophragma hydrangeoides), Amur maackia (Maackia amurensis), and summer blooming Spirea (Spiraea japonica). Herbaceous plants seen in bloom include: summer flowering roses (Rosa sp.), clematis vines (Clematis paniculata), spiderwort (Tradescantia sp.), water lily (Nymphaea odorata), hardy cranesbill (Geranium sp.), ox-eye daisy (Leucanthemum vulgare), bee balm (Monarda didyma), hosta (Hosta sp.), rudbeckia (Rudbeckia fulgida), daylilies (Hemerocallis sp.), astilbes (Astilbe sp.), coneflower (Echinacea purpurea), milkweed (Asclepias syriaca), and yarrow (Achillea millefolium). Many annuals are also adding color to the landscape.

Pests/Problems:

Magnolia scale (Neolecanium cornuparvum) was observed on saucer Magnolia. These are large scales with a white waxy covering. Small infestations can be removed any time of year by pruning out infested branches. Horticultural oils applied after the crawlers have emerged are effective in reducing the scale population. Japanese beetles (Popillia japonica) were observed causing damage to some plants. Adult Japanese beetles skeletonize leaves by feeding on tissue between the major veins, giving them a lace-like appearance. Weeds are thriving in the landscape. Poison ivy and other invasive weeds are also thriving. Take caution to avoid contact with poison ivy when walking or working in the woods. Remember also that ticks and mosquitoes are still very active. Take measures to protect yourself while working outdoors, especially at dawn or at dusk.

East (Boston)

General Conditions: Over the past two weeks we experienced a stretch of overcast rainy days followed by increasing temperatures and humidity. Daytime temperatures averaged 82°F with a high of 94°F on the sixth. Overnight temperatures averaged 67°F with a high of 71°F and a low of 63°F, never really cooling off. We accumulated 1.94 inches of precipitation, falling on seven of the past 14 days. We received 1.04 inches over three days from July 2nd through the 4th, and another 0.70 inches which fell on July 10th and 11th. The landscape is responding to the recent conditions; trees and shrubs are putting on significant new growth. Plants in bloom include; Campsis radicans (trumpet vine), Clethra alnifolia (summer sweet), Hydrangea arborescens ‘Annabelle’ (smooth hydrangea), and Hydrangea quercifolia (oakleaf hydrangea).

Pests/Problems: Current conditions continue to promote fungal disease. Leaf spot  and mildew are prevalent throughout the landscape. The foliage on Amelanchier spp. (serviceberry), Cornus florida (flowering dogwood), Malus spp. (crabapple), and Rosa spp. (rose) appears particularly susceptible. Rabbits continue to feast in the landscape and have been especially devastating to recent perennial and shrub plantings.

Metro West (Acton)

General Conditions:

Summer has arrived and we’ve experienced some hot and humid days to prove it, but for the most part it’s been a warm, wet, hot, and humid two weeks. Unfortunately, the July 4th holiday was not one of those hot and dry days. A high temperature of 77°F and 0.35” of rain was recorded. The high temperature for this two-week reporting period was on the 6th with 91°F recorded and, believe it or not, the only 90° day for this reporting period. The historical monthly average rainfall for June is 3.93” and we fell just shy of that mark with 3.68” of rain recorded. The average monthly precipitation for July is 3.43” and as of the 11th, 2.75” of rain has fallen for the month so far.

Pests/Problems:

Observed in the landscape these past two weeks were cedar apple rust on Amelanchier sp. (serviceberry); powdery mildew on Cornus florida (dogwood), Paeonia sp. (peony), and Syringa sp. (lilac); and lily leaf beetle on Lilium sp. Ailanthus altissima (tree of heaven), an invasive tree, has set seed and is now highly visible and showy because its seeds (samaras) are reddish in color, are plentiful, and grow in clusters.

Central Region (Boylston)

General Conditions:

This reporting period we have had some hot and humid summer days with above average amounts of precipitation. Daily temperatures ranged from the mid 70’s to high 80’s, and overnight temperatures ranged between the low 60’s and low 70’s. The July 4th holiday weekend was impacted by several rain events which delivered a little over 3.5” of rain across 3 days. This past week we received almost 3” of rain in a single day, totaling almost 8” for this period. While we are dealing with the wash out, many plants in our landscape are coming into bloom like sourwood (Oxydendrum arboreum), bottlebrush buckeye (Aesculus parvifolia), scarlet beebalm (Monarda didyma), butterfly milkweed (Asclepias tuberosa), and black-eyed Susan (Rudbeckia spp.)

Pests/Problems:

Very few pest problems to report. We’ve begun to notice leaf cutter bees (Megachile spp.) and charismatic native wasps such as the great black wasp (Sphex pensylvanicus) returning to the landscape. On a joyous note, we’ve spotted one of our first monarch butterflies (Danaus plexippus) of the season!

Pioneer Valley (Amherst)

General Conditions:

As we enter the second half of July, deep in the heart of summer, the landscape remains lush and vibrant. Over this past reporting period, temperatures were mild to hot with a thick blanket of unending humidity. Since 6/23, moisture-laden air has persisted with afternoon dew points regularly peaking in the lower to mid-70s and only brief periods of relief. When temperatures have risen, the heat index has boiled over the 100°F threshold (e.g. 7/5–7/8). A steady supply of scattered thunderstorms have provided plentiful moisture across the tri-counties and soils are wet to saturated. Portions of western Hampshire and Franklin Counties have seen huge volumes of rain since late June, with some stations recording >10ʺ. Localized downpours, like the one over Springfield on 7/8, have deposited >1ʺ in short periods of time. Heavy rain on the morning of 7/10 contributed several additional inches of precipitation that led to some damaging flooding. Several rivers (Green, Deerfield, Mill, and West Branch of the Westfield) reached minor flood stage on 7/10 with western hill towns experiencing road washouts and localized flooding. The Connecticut River crested into moderate flood stage on 7/11 and 7/12 and low lying areas in Greenfield, Deerfield, Hatfield, Northampton, and Easthampton saw significant overflow. From 6/28 to 7/12, the following precipitation totals were recorded: 11.67″ (Ashfield), 7.44″ (Deerfield), 6.22″ (Belchertown), 5.87″ (Easthampton) and 5.58″ (Chicopee). Trees, shrubs, perennials, and annuals on well-drained soils are thriving under the current conditions, as many appear robust and healthy. Oaks, witchhazel, red maple, among many other plants, have flushed new growth due to the abundance of rainfall. In some cases, this new growth is distinctly red in color. This is due to the production of anthocyanins to protect this tender new growth from sunscald. Mushrooms produced by mycorrhizal fungi are locally profuse, especially in shaded landscapes rich with oaks.

Pests/Problems:

Invasive scarab beetle (Asiatic, Oriental and Japanese) populations are peaking at this time. Damage can be observed across a range of woody and non-woody plants. Twig and branch cankering fungi are very active with the mild temperatures, regular rainfall, and high humidity. Fungi like Nectria, Botryosphaeria, Diplodia, Phomopsis, and Cytospora are actively sporulating and spreading throughout infected tree and shrub canopies. Trees that were drought-stressed in 2022 could be harboring significant infections. Cedar-quince rust is common on serviceberry and hawthorn. Pink-colored, spore-bearing tendrils can be found on infected fruit, gall-like twig cankers (serviceberry), and distorted shoot tips (hawthorn). On serviceberry, leaf yellowing and premature shedding may be present on cankered, interior canopy twigs. Sycamores were able to push new growth at the end of June and early July and many trees appear respectable at present. While this was a worse than average year for sycamore anthracnose, trees ultimately did recover. This is a good time to be mindful of bald-faced hornets. Their large nests can be obscured in tree and shrub canopies. If the nest is disturbed while weeding or pruning, they will aggressively sting. Ground nests of wasps should also be carefully scouted for at this time, especially when working new properties. Mosquito populations are still very high but they mostly avoid full sun settings during the day. Black flies during the morning and evening hours continue to swarm. Despite the widespread damage that Japanese knotweed experienced from the 5/18 frost, rapid growth has since resumed.

Berkshire Region (West Stockbridge)

General Conditions:

The past two weeks have seen a steady rise in daily temperatures and frequent rains. The highest temperatures in the county occurred on July 6th with 92°F in North Adams, and 89°F in both Pittsfield and Richmond. The coolest temperatures for the scouting period were on the morning of June 30th: 55°F in Richmond, 58°F in Pittsfield, and 59°F in North Adams. The most significant weather event started with rain on Sunday July 9 and continued into Monday July 10. The rain was often very heavy. However, the amount of rain and impacts varied considerably, depending upon location. The two-day storm left 2.07 inches here in West Stockbridge. Lesser amounts were recorded in Monterey (1.94 inches) and New Ashford (1.63 inches). However, Great Barrington and Adams rainfall measured 4.20 inches from the storm.  Given the great variations in terrain, including altitude, throughout the county, it is not unusual to see large variations in weather conditions from town to town. Flooding was reported in several towns and numerous washouts of roads and trails occurred. As would be expected after such an event, most soils are now saturated and will remain so for the foreseeable future, as the forecasts as of this reporting date call for daily thunderstorms over the next week. Currently, plant growth has shown no negative growth effects from the rain, except for those in flooded sites, and the landscape is quite colorful with a large array of annual and perennial flowering plants in full bloom. Turfgrass growth has benefited from the rain and is growing rapidly.

Pests/Problems:

Of course, for some areas of the county, flooding is a main concern. Much of the Stockbridge Golf Course was under water for several days after the heavy rains of Sunday and Monday. Though plants seem little affected at this point, continued saturation of soil can result in significant root death. The combination of high temperatures and frequent rains also increase the opportunities for plant diseases. With a few exceptions, there have not been many plant diseases up to this point in the season. Among the diseases observed are the ubiquitous cedar apple rust, apple scab, and black spot on roses. There are also various leaf spot diseases on trees including Phyllosticta leaf spot (Phyllosticta minima) on red maples. Insect problems are also not too common. Lily leaf beetles remain active as are aphids on a variety of herbaceous plants. Japanese beetles made an appearance a few weeks ago and their numbers are steadily building. Spongy moth caterpillars have just about disappeared and left little damage to trees and shrubs. Yet, there have been several reports of severe defoliation by these caterpillars in nearby areas of New York State. Reportedly, the spongy moths have gone west. Horticulturist Amie Combs of Monterey reported finding Yucca beetles on container grown yuccas. Apparently, this is not a common pest in this region.

Regional Scouting Credits

• CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
• SOUTHEAST REGION - Brian McMahon, Arborist, reporting from the Dighton area.
• NORTH SHORE REGION - Geoffrey Njue, Green Industry Specialist, UMass Extension, reporting from the Long Hill Reservation, Beverly.
• EAST REGION - Kit Ganshaw & Sue Pfeiffer, Horticulturists reporting from the Boston area.
• METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
• CENTRAL REGION - Mark Richardson, Director of Horticulture reporting from New England Botanic Garden at Tower Hill, Boylston.
• PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from Amherst.
• BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

Beech Leaf Disease (BLD) Management:

There continues to be considerable uncertainty and debate about the best course of action for BLD management. One option is the application of phosphites as a soil drench around the base of the tree for root uptake into the canopy. Presently, it’s suspected that a lower trunk bark spray may not be adequately mobilized into the canopy. While PolyPhosphite 30 has garnered significant attention as the product of choice, any phosphite product with the active ingredient of mono- and di-potassium salts of Phosphorous acid can be used (e.g. Rampart, Reliant, Fungi-phite, Fosphite, etc.). It is not entirely clear how phosphites help to manage BLD and for many trees, application may provide little to no control. Phosphites have two modes of action: (1) they are weakly fungicidal at high concentrations, and (2) they stimulate the tree’s natural defense response. The second mode of action is likely how phosphites are helping to restore vigor to some BLD-infested trees. It’s important to note that phosphites are not fertilizers and they provide no useable source of Phosphorus to woody plants. The labeled interval for a soil drench on woody ornamentals among several phosphite products is limited to one application per month. It is probable that monthly applications may be required during the growing season for the greatest level of success.

Fluopyram is a nematicide that may provide some level of BLD control. There is a moderate risk of resistance when using this systemic product. Meaning, repeated usage of fluopyram without rotating to another class of nematicide can produce a nematode population that is resistant to the chemical. Broadform (fluopyram + trifloxystrobin) is labeled for use on woody ornamentals in commercial and residential landscapes throughout New England and portions of New York State. Luna Experience (fluopyram + tebuconazole) is not labeled for use on woody ornamentals in Massachusetts, but an emergency use order exists in Connecticut. For additional information, see the following fact sheet on BLD: https://ag.umass.edu/landscape/fact-sheets/beech-leaf-disease

Recent pests, pathogens, or problems of interest seen in the UMass Extension Plant Diagnostic Lab, a select few:

Root and lower trunk rot of a mature sugar maple (Acer saccharum) caused by Kretzschmaria deusta. The tree has a dbh of 48″ and resides adjacent to an asphalt driveway at a mid-19th century colonial home. It’s possible the tree was established as part of a mass planting of 1,000 trees over a three-day period in 1846 in the town of Sheffield, MA. The new homeowners have only limited experience with the tree (18 months), which has exhibited worsening canopy dieback from 2022 to 2023. Examination of the root flare this spring and early summer revealed an extensive number of fruiting bodies produced by the root and lower trunk rot pathogen Kretzschmaria deusta (left image). Unlike most wood-rotting pathogens, Kretzschmaria fruiting bodies are flattened, irregularly-shaped, and grey with white margins. The sheer number of fruiting bodies indicated severe decay but given the historical significance of the tree, an assessment using sonic and electrical resistance tomography was requested. As expected, there was extensive decay in the lower trunk. While the sonic tomogram (center image) revealed a large area of damaged wood (indicated by the green, violet, and blue area of the tomogram), sonic tomography can often underestimate decay caused by K. deusta due to the pattern of decay. Specifically, the fungus preferentially degrades cellulose leading to significant strength loss, but the wood still appears firm due to the remaining matrix of pectin and lignin (known as the middle lamella). Therefore, the electrical resistance (ER) tomogram (right image) often reveals the true extent of the damage. In the ER tomogram, the dashed black circle encompasses a large area of high conductivity (higher moisture) that likely represents the actual area of decay. However, in the very center of the ER tomogram, an area of higher electrical resistance (red) is present and this represents a developing cavity – the endpoint of the decay process. Further up the trunk, there were several perennial conks produced by Fomes fomentarius. This weakly pathogenic trunk rot fungus is often found on dead birch in forest settings and its presence beneath the union of several canopy leaders was very concerning. Unfortunately, but without reservation, the tree is slated for removal.  

Sirococcus blight (Sirococcus conigenus) on Blue Atlas cedar (Cedrus atlantica ‘Glauca’). The tree is approximately 40-years-old and resides in a coastal town on the north shore with full sun in loam-based soils with drip irrigation. The tree has been healthy in previous years but this spring, both new and older growth turned brown and needles were prematurely shedding. Sirococcus is a cankering pathogen that has a broad host range among forest and landscape conifers. It often attacks young, succulent tissues and then may expand to older twigs and small branches. It is not known to attack larger (i.e. >3” diameter) branches, primarily infecting shoot tips. According to Sinclair (p. 118; 2005), outbreaks of Sirococcus blight are most common in coastal areas with mild, moist weather and this seems to align with samples submitted to the UMass Plant Diagnostic Lab. When Siroccocus blight is encountered, samples typically originate from landscapes near the ocean.

Foliar anthracnose, caused by Colletotrichum, on lilac (Syringa) and magnolia (Magnolia). Three plants on differing properties with similar symptoms. Specifically, dark blotches on mature foliage and a collapse of the newest growth at the shoot tips. On all three submitted samples, pink-colored spore masses were clearly visible on the blighted shoots and leaves. Collteotrichum has a very broad host range among deciduous hardwoods and conifers, causing leaf spots, blotches, shoot blight and twig/branch cankers. The mild temperatures and regular rainfall have provided ideal conditions for Colleotrichum.   

Canopy dieback of Norway spruce (Picea abies) caused by the Norway spruce gall midge (Piceacecis abietiperda), eastern spruce gall adelgid (Adelges abietis), Stigmina needle cast (Stigmina lautii) and Phomopsis twig and branch canker (Phomopsis sp.). The tree is approximately 75-years-old and over the past several years has exhibited a noticeable crown thinning, especially towards the interior of the canopy. It resides in full sun in a garden bed near a house, garage and paved driveway. Individually, none of these pests or pathogens can kill an otherwise healthy Norway spruce. But together, in combination with abiotic stress like drought, they can significantly contribute to a slow decline. Treating the gall midge and adelgid on large Norway spruce can be very challenging. The same can be said for needle cast and twig/branch cankering infections. The sheer volume of infested/infected material makes the task of management a problem even with chemical treatment.  

See our new UMass Extension fact sheet on Brown Spot Needle Blight (Lecanosticta acicola.

Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass Amherst

Insects and Other Arthropods

Citizen Science Opportunity: Reporting Native Ground Nesting Bees

The Cornell College of Agriculture and Life Sciences and the Cornell Atkinson Center for Sustainability and the Ground Nesting Bees Community Science Project are asking for your help collecting data on native bee populations and nesting sites. Your contributions will help scientists better understand the importance of native bees and how to protect them in our local environments.

What to Look For: Safely monitor ground nesting bees from early spring to late summer. Entrances in grass and soil are indicators of bee activity. Upload a photo of a bee entering or exiting its nest to iNaturalist (GNbee). To learn more, visit: https://www.gnbee.org/ and upload your photos here.

Some notes on safety: take appropriate precautions if you are allergic to bee stings. While many ground nesting bees or wasps do not sting, it is not a guarantee that you will not encounter a stinging species if participating.

Interesting Insects Reported or Seen Recently:

• Red Milkweed Beetle: (Tetraopes tetrophthalmus) For those of you growing milkweed for the monarchs, you may find from time to time that other visitors are present and feeding on your plants. Who are we to say who deserves to feast on milkweed and who does not? If you are an insect and your system can tolerate feeding on a plant full of toxins - cardiac glycosides which are concentrated in the milkweed’s sap – I would say you have earned the right to feed on this plant. In fact, the red milkweed beetles sequester these toxins in their bodies, employing a well-known chemical defense strategy which is also practiced by monarch butterflies, milkweed tussock moths, and certain true bugs that feed on this host. As with the red milkweed beetle, bright colors are often a warning sign for would-be predators that say “Hey, I’m poisonous…or at least distasteful”. The beetles found in this photo were seen on 7/10/2023 in Amherst, MA. (Photo courtesy of Angie Madeiras, UMass Extension.) This beetle is member of the same family as the Asian longhorned beetle (the Cerambycidae, or long horned beetles). Adults spend most of their time on milkweed, where they can be found resting, feeding, and mating. Adults can feed on all above ground plant parts. Eggs are typically laid near the root crown. Eggs hatch and larval development occurs in the roots of the plant.

Current Nuisance Problems of Note:

• Deer Tick/Blacklegged Tick: Ixodes scapularis adults are active all winter and spring, as they typically are from October through May, and “quest” or search for hosts at any point when daytime temperatures are above freezing. Engorged females survive the winter and lay 1,500+ eggs in the forest leaf litter beginning around Memorial Day (late May). For images of all deer tick life stages, along with an outline of the diseases they carry, visit: https://www.capecod.gov/departments/cooperative-extension/programs/ticks-bugs/ or https://web.uri.edu/tickencounter/species/blacklegged-tick/.

Anyone working in the yard and garden should be aware that there is the potential to encounter deer ticks. The deer tick or blacklegged tick can transmit Lyme disease, human babesiosis, human anaplasmosis, and other diseases. Preventative activities, such as daily tick checks, wearing appropriate clothing, and permethrin treatments for clothing (according to label instructions) can aid in reducing the risk that a tick will become attached to your body. If a tick cannot attach and feed, it will not transmit disease. For more information about personal protective measures, visit: https://www.capecod.gov/departments/cooperative-extension/programs/ticks-bugs/.

The Center for Agriculture, Food, and the Environment provides a list of potential tick identification and testing resources.

*In the news: UMass Amherst has now been designated as the location for the New England Center of Excellence in Vector-Borne Diseases (NEWVEC). This CDC (Centers for Disease Control and Prevention) funded center will work to reduce the risk of vector-borne diseases spread by ticks, mosquitoes, and other blood-sucking insects or insect relatives in New England. For more information and to contact NEWVEC, visit: https://www.newvec.org/. To contact the center for more information about their Spring 2023 Project ITCH (“Is Tick Control Helping”), visit: https://www.newvec.org/itch .

Note: Dog ticks (Dermacentor variabilis) continue to be noticeably active in parts of Berkshire and Hampshire County in 2023. They are present in large numbers this year even in environments where tick activity is typically low, such as in mowed lawns.

• Mosquitoes: According to the Massachusetts Bureau of Infectious Disease and Laboratory Science and the Department of Public Health, there are at least 51 different species of mosquito found in Massachusetts. Mosquitoes belong to the Order Diptera (true flies) and the Family Culicidae (mosquitoes). As such, they undergo complete metamorphosis, and possess four major life stages: egg, larva, pupa, and adult. Adult mosquitoes are the only stage that flies and many female mosquitoes only live for 2 weeks (although the life cycle and timing will depend upon the species). Only female mosquitoes bite to take a blood meal, and this is so they can make eggs. Mosquitoes need water to lay their eggs in, so they are often found in wet or damp locations and around plants. Different species prefer different habitats. It is possible to be bitten by a mosquito at any time of the day, and again timing depends upon the species. Many are particularly active from just before dusk, through the night, and until dawn. Mosquito bites are not only itchy and annoying, but they can be associated with greater health risks. Certain mosquitoes vector pathogens that cause diseases such as West Nile virus (WNV) and eastern equine encephalitis (EEE).

Click here for more information about mosquitoes in Massachusetts.

EEE and WNV testing and tracking for this season began on June 12, 2023. The Massachusetts Department of Public Health tracks animal cases, human cases, and mosquito positive samples from traps from June through October in Massachusetts. The first West Nile Virus positive mosquito sample was collected on July 6, 2023, in the town of Brookline in Norfolk County, MA. State officials announced this detection at https://www.mass.gov/news/state-public-health-officials-announce-seasons-first-west-nile-virus-positive-mosquito-sample. Click here for more information.

There are ways to protect yourself against mosquitoes, including wearing long-sleeved shirts and long pants, keeping mosquitoes outside by using tight-fitting window and door screens, and using insect repellents as directed. Products containing the active ingredients DEET, permethrin, IR3535, picaridin, and oil of lemon eucalyptus provide protection against mosquitoes. Be aware that not all of these can be safely used on young children. Read and follow all label instructions for safety and proper use.

Click here for more information about mosquito repellents.

• Wasps/Hornets: Many wasps are predators of other arthropods, including pest insects such as certain caterpillars that feed on trees and shrubs. Adult wasps hunt prey and bring it back to their nest where young are being reared, as food for the immature wasps. A common such example are the paper wasps (Polistes spp.) who rear their young on chewed up insects. They may be seen searching plants for caterpillars and other soft-bodied larvae to feed their young. Paper wasps can sting, and will defend their nests, which are open-celled paper nests that are not covered with a papery “envelope”. These open-celled nests may be seen hanging from eaves or other outdoor building structures. Aerial yellow jackets and hornets create large aerial nests that are covered with a papery shell or “envelope”. Common yellow jacket species include those in the genus Vespula. Dolichovespula maculata is commonly known as the baldfaced hornet, although it is not a true hornet. The European hornet (Vespa crabro) is three times the size of a yellow jacket and may be confused for the northern* giant hornet (Vespa mandarinia). The European hornet is known to Massachusetts, but the northern giant hornet is not. The European hornet is known to Massachusetts, but the northern giant hornet is not. Homeowners in Massachusetts are beginning to report sightings of the European hornet in 2023. European hornets have black, tear-drop shaped markings on their abdomens, but northern giant hornets do not. If you are concerned that you have found or photographed a northern giant hornet, please report it here: https://massnrc.org/pests/report.aspx. Paper wasps and aerial yellowjackets overwinter as fertilized females (queens) and a single female produces a new nest annually in the late spring. Queens start new nests, lay eggs, and rear new wasps to assist in colony/nest development.Nests are abandoned at the end of the season. Some people are allergic to stinging insects, so care should be taken around wasp/hornet nests. Unlike the European honeybee (Apis mellifera), wasps and hornets do not have barbed stingers, and therefore can sting repeatedly when defending their nests. It is best to avoid them, and if that cannot be done and assistance is needed to remove them, consult a professional.

*Read more about the common name change for Vespa mandarinia.

Woody ornamental insect and non-insect arthropod pests to consider, a selected few:

Highlighted Invasive Insects & Other Organisms Update:

• Spongy Moth: Lymantria dispar activity in Berkshire County, MA is already nearing an end! On July 8 and July 9, 2023, adult male spongy moths could be seen frantically flying in search of flightless females to mate in Dalton and Hinsdale, MA. While maturation of caterpillars and subsequent pupation and adult emergence do not occur at the exact same time for all individuals in the population, it can be expected that the feeding by spongy moth caterpillars in these areas is at or near its end for 2023. See the Berkshire Region report above for further updates.

Nicole Keleher, MA Department of Conservation and Recreation, Forest Health Program, reports that spongy moth defoliation in Berkshire County, overall, seems less abundant this year than in recent years. She reports that widespread frost damage to oaks makes it more challenging to notice areas that had low to moderate levels of defoliation. Keleher also reports that spongy moth defoliation in Franklin County (in areas where these caterpillars have been abundant in recent years) was still severe along Rt. 2 in the Erving, MA area. In those areas, a clear distinction between spongy moth defoliation and frost damage to oaks could be seen. There is concern in those areas of Franklin County for the long term health of the impacted oaks. Thank you to the MA Department of Conservation and Recreation for these updates!

For more information about spongy moth, view the first episode of InsectXaminer.

Why did the common name for Lymantria dispar change recently? Read more here.

• Spotted Lanternfly: (Lycorma delicatula, SLF) is a non-native, invasive insect that feeds on over 103 species of plants, including many trees and shrubs that are important in our landscapes. It overwinters as an egg mass, which the adult female insect lays on just about any flat surface. Pictures of egg masses can be seen here.

Updates about spotted lanternfly egg hatch in Massachusetts are now available from MDAR at https://massnrc.org/pests/blog/?p=3205.
SLF egg hatch has now occurred at all four locations in Massachusetts where this insect has become established. Eggs seem to have hatched earliest in Springfield, MA and at that location, MDAR reports seeing both first and second instar nymphs active at this time (as of 6/21/2023).

Currently, the only established populations of spotted lanternfly in Massachusetts are in Fitchburg, Shrewsbury, Worcester, and Springfield MA. Therefore, there is no reason to be preemptively treating for this insect in other areas of Massachusetts. If you suspect you have found spotted lanternfly in additional locations, please report it immediately to MDAR here. If you are living and working in the Fitchburg, Shrewsbury, Worcester, and Springfield, MA areas, please be vigilant and continue to report anything suspicious.

For More Information:

From UMass Extension:

*New*: Spotted Lanternfly Management Guide for Professionals

*Note that management may only be necessary in areas where this insect has become established in Massachusetts, and if high value host plants are at risk. Preemptive management of the spotted lanternfly is not recommended.

Spotted Lanternfly Fact Sheet

Check out the InsectXaminer Episode about spotted lanternfly adults and egg masses!

From the MA Department of Agricultural Resources (MDAR):

Spotted Lanternfly Fact Sheet and Map of Locations in MA

Spotted Lanternfly Management Guide for Homeowners in Infested Areas

*New*: Spotted Lanternfly Look-alikes in MA

*New*: Spotted Lanternfly Egg Mass Look-alikes

• Asian Longhorned Beetle: (Anoplophora glabripennis, ALB) Look for signs of an ALB infestation which include perfectly round exit holes (about the size of a dime), shallow oval or round scars in the bark where a female has chewed an egg site, or sawdust-like frass (excrement) on the ground nearby host trees or caught in between branches. Be advised that other, native insects may create perfectly round exit holes or sawdust-like frass, which can be confused with signs of ALB activity.

Adult Asian longhorned beetles typically begin to emerge from trees by July 1st in Massachusetts. It is important to take photographs of and report any suspicious longhorned beetles to the Asian Longhorned Beetle Eradication Program phone numbers listed below.

The regulated area for Asian longhorned beetle is 110 square miles encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, please call the Asian Lonbghorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938.

Report an Asian longhorned beetle find online or compare it to common insect look-alikes here.

• White Spotted Pine Sawyer (WSPS): Monochamus scutellatus adults can emerge in late May throughout July, depending on local temperatures. This is a native insect in Massachusetts and is usually not a pest. Larvae develop in weakened or recently dead conifers, particularly eastern white pine (Pinus strobus). However, the white spotted pine sawyer looks very similar to the invasive Asian Longhorned Beetle, Anoplophora glabripennis, ALB. ALB adults do not emerge in Massachusetts until July and August. Beginning in July, look for the key difference between WSPS and ALB adults, which is a white spot in the top center of the wing covers (the scutellum) on the back of the beetle. White spotted pine sawyer will have this white spot, whereas Asian longhorned beetle will not. Both insects can have other white spots on the rest of their wing covers; however, the difference in the color of the scutellum is a key characteristic. See the Asian longhorned beetle entry above for more information about that non-native insect.
• Emerald Ash Borer: (Agrilus planipennis, EAB) has been detected in at least 11 out of the 14 counties in Massachusetts. A map of these locations across the state may be found at https://ag.umass.edu/fact-sheets/emerald-ash-borer . Additional information about this insect is provided by the MA Department of Conservation and Recreation at https://storymaps.arcgis.com/stories/b60f63199fa14805a8b9f7c82447a25b.

This wood-boring beetle readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus) and has been reported in cultivated olive (Olea europaea). Signs of an EAB infested tree may include D-shaped exit holes in the bark (from adult emergence), “blonding” or lighter coloration of the ash bark from woodpecker feeding (chipping away of the bark as they search for larvae beneath), and serpentine galleries visible through splits in the bark, from larval feeding beneath. It is interesting to note that woodpeckers are capable of eating 30-95% of the emerald ash borer larvae found in a single tree (Murphy et al. 2018). Unfortunately, despite high predation rates, EAB populations continue to grow. However, there is hope that biological control efforts will eventually catch up with the emerald ash borer population and preserve some of our native ash tree species for the future.

• Jumping Worms: Amynthas spp. earthworms, collectively referred to as “jumping or crazy or snake” worms, overwinter as eggs in tiny, mustard-seed sized cocoons found in the soil or other substrate (ex. compost). Immature jumping worms hatch from their eggs by approximately mid-to-late May. It may be impossible to see them at first, and it may be more likely that jumping worms are noticed when the first adults begin to appear at the end of May and in June. It is easy to misidentify jumping worms (ex. mistake European earthworms for jumping worms) if only juveniles are found. In August and September, most jumping worms have matured into the adult life stage and identification of infestations is more likely to occur at that time of year.

For More Information, see these UMass Extension Fact Sheets:

Earthworms in Massachusetts – History, Concerns, and Benefits

Jumping/Crazy/Snake Worms – Amynthas spp.

A Summary of the Information Shared at UMass Extension’s Jumping Worm Conference in January 2022

Invasive Jumping Worm Frequently Asked Questions (Over 70 Questions and their Answers)

Tree & Shrub Insect Pests (Native and Invasive):

• Andromeda Lace Bug: Stephanitis takeyai is most commonly encountered on Japanese Andromeda. Eggs are tiny and inserted into the midveins on the lower surface of the leaf and covered with a coating that hardens into a protective covering. 5 nymphal stages are reported. Nymphs are different in appearance from the adults, often covered with spiky protrusions. 3-4 generations per year have been observed in New England, with most activity seen between late-May into September (starting at approximately 120 GDD’s, Base 50°F). Both nymphs and adults can be seen feeding on leaf undersides. Adults have delicate, lace-like wings and what appears to be an "inflated hood" that covers their head. Adults are approximately 1/8 of an inch long. Arrived in the US in Connecticut in 1945 from Japan (Johnson and Lyon, 1991).

Can cause severe injury to Japanese andromeda, especially those in full sun. Mountain Andromeda (Pieris floribunda) is highly resistant to this pest. Like other lace bugs, this insect uses piercing-sucking mouthparts to drain plant fluids from the undersides of the leaves. Damage may be first noticed on the upper leaf surface, causing stippling and chlorosis (yellow or off-white coloration). Lace bug damage is distinguished from that of other insects upon inspecting the lower leaf surface for black, shiny spots, "shed" skins from the insects, and adult and nymphal lace bugs themselves.

A first sign of potential lace bug infestation is stippling or yellow/white colored spots or chlorosis on host plant leaf surfaces. Lace bugs excrete a shiny, black, tar-like excrement that can often be found on the undersides of infested host plant leaves. Flip leaves over to inspect for this when lace bug damage is suspected.

Mountain Andromeda (Pieris floribunda) is considered to be highly resistant to this insect and can be used as an alternative for such plantings, along with other lace bug-resistant cultivars. Consider replacing Japanese Andromeda with mountain andromeda as a way to manage for this pest. Natural enemies are usually predators, and sometimes not present in large enough numbers in landscapes to reduce lace bug populations. Structurally and (plant) species complex landscapes have been shown to reduce azalea lace bug (Stephanitis pyrioides) populations through the increase of natural enemies.

• Arborvitae Leafminer: In New England and eastern Canada, four species of leafminers are known to infest arborvitae. These include Argyresthia thuiella, A. freyella, A. aureoargentella, and Coleotechnites thujaella. The arborvitae leafminer, A. thuiella, is the most abundant of these and has the greatest known range when compared to the others. (It is also found in the Mid-Atlantic States and as far west as Missouri). Moths of this species appear from mid-June to mid-July and lay their eggs. The damage caused by all of these species is nearly identical. Trees, however, have been reported to lose up to 80% of their foliage due to arborvitae leafminer and still survive. At least 27 species of parasites have been reported as natural enemies of arborvitae leafminers, the most significant of which may be a parasitic wasp (Pentacnemus bucculatricis). Arborvitae leafminer damage causes the tips of shoots and foliage to turn yellow and brown. If infestations are light, prune out infested tips.
• Asiatic Garden Beetle: Maladera castanea adults are active and are typically most abundant in July and August. These rusty-red colored beetles are bullet-shaped and active at night. They are often attracted to porch lights. This beetle feeds on a number of ornamental plants, defoliating leaves by giving the edges a ragged appearance and also feeding on blossoms. Butterfly bush, rose, dahlia, aster, and chrysanthemum can be favored hosts.

• Azalea Lace Bug: Stephanitis pyrioides is native to Japan. The azalea lace bug deposits tiny eggs on the midveins on leaf undersides. They then cover the area where the egg was inserted with a brownish material that hardens into a protective covering. Each female may lay up to 300 eggs (University of Florida). Nymphs hatch from the eggs and pass through 5 instars. The length of time this takes depends on temperature. Between 2 and 4 generations may be completed in a single year. In Maryland, there are four generations per year. Adults are approximately 1/10 of an inch in length with lacy, cream colored, transparent wings held flat against the back of the insect. Wings also have black/brown patches. Adults of this species also possess a "hood" over their head. Nymphs are colorless upon hatch from the egg, but develop a black color as they mature and are covered in spiny protrusions.

Immatures and adults use piercing-sucking mouthparts to remove plant fluids from leaf tissues. This feeding leaves behind white-yellow stippling on the upper surface of host plant leaves, even though the insects themselves feed on the underside of the leaf. Plants in full sun are often particularly damaged by these insects. In heavy infestations, plants in full sun may be killed by the feeding of the azalea lace bug.

Begin scouting for azalea lace bugs when 120 GDD’s (Base 50°F) are reached. This species is active throughout the summer, following. Look for dark, black tar-like spots of excrement deposited by immature and adult lace bugs on the underside of susceptible host plant leaves, especially on leaves with white-yellow stippling visible on the upper surface. If lace bugs are not already known to the location, check susceptible hosts located in full sun first. Monitor plants for lace bug feeding from late April through the summer.

Plant azaleas in partial shade. Resistance has been reported in Rhododendron atlanticum, R. arborescens, R. canescens, R. periclymenoides, and R. prunifolium.

Many of the natural enemies reported for this insect are predators. They are rarely abundant enough to reduce damaging populations of lace bugs, especially on plants in sunny locations. Structurally and (plant) species complex landscapes have been shown to reduce azalea lace bug (Stephanitis pyrioides) populations through the increase of natural enemies.

• Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs. This insect overwinters in the egg stage, within the bags of deceased females from last season. Eggs may hatch and young larvae are observed feeding around mid-June, or roughly between 600-900 GDD’s. Newly hatched and feeding bagworm caterpillars are small and less likely to be noticed. By late July and August, these caterpillars will be large and their feeding noticeable on individual trees and shrubs.

• Cottony Taxus Scale: Pulvinaria floccifera, also referred to as the cottony camellia scale, utilizes such hosts as taxus, camellia, holly, hydrangea, Japanese maple, euonymus, magnolia, and jasmine, among others. Females have laid the long, narrow, white and fluted egg sac that makes them much more noticeable. Eggs will hatch over an extended period of 6 weeks and crawlers may be treated between 802-1388 GDD’s. This insect can cause the host to appear off-color. They also produce honeydew which promotes sooty mold growth. Dieback is not common with this insect. Target the underside of the foliage. Horticultural oil, neem oil, and insecticidal soaps may be used to manage these soft scales. Reduced risk options help preserve natural enemies.
• Dogwood Borer: Synanthedon scitula is a species of clearwing moth whose larvae bore not only into dogwood (Cornus), but hosts also include flowering cherry, chestnut, apple, mountain ash, hickory, pecan, willow, birch, bayberry, oak, hazel, myrtle, and others. Kousa dogwood appear to be resistant to this species. Signs include the sloughing of loose bark, brown frass, particularly near bark cracks and wounds, dead branches, and adventitious growth. The timing of adult emergence can be expected when dogwood flower petals are dropping and weigela begins to bloom. Adult moth flights continue from then until September. Emergence in some hosts (ex. apple) appears to be delayed, but this differs depending upon the location in this insect’s range. Eggs are laid singly, or in small groups, on smooth and rough bark. Female moths preferentially lay eggs near wounded bark. After hatch, larvae wander until they find a suitable entrance point into the bark. This includes wounds, scars, or branch crotches. This insect may also be found in twig galls caused by other insects or fungi. Larvae feed on phloem and cambium. Fully grown larvae are white with a light brown head and approx. ½ inch long. Pheromone traps and lures are useful for determining the timing of adult moth emergence and subsequent management.
• Dogwood Sawfly: Macremphytus tarsatus has one generation per year. The larvae of the dogwood sawfly overwinter in decaying wood and occasionally compromised structural timber. An overwintering "cell" is created in this soft wood. Pupation occurs in the springtime and adults can take a lengthy time to emerge, roughly between late May and July. 100+ eggs are laid in groups on the underside of leaves. Eggs hatch and the larvae feed gregariously, initially skeletonizing leaves. As the caterpillars grow in size, they are capable of eating the entire leaf with the exception of the midvein. Larval appearance varies greatly throughout instars, so much so that one might mistake them for multiple species. Early instars are translucent and yellow, but as the caterpillars grow they develop black spots (over yellow) and become covered in a white powder-like material. Larvae and their shed skins may resemble bird droppings. Full grown larvae begin to wander in search of a suitable overwintering location. Rotting wood lying on the ground is preferred for this.

Foliage of dogwood, especially gray dogwood (Cornus racemosa) may be impacted. Skeletonizes leaves at first, then eats all but the midvein.

• Fall Webworm: Hyphantria cunea is native to North America and Mexico. It is now considered a world-wide pest, as it has spread throughout much of Europe and Asia. (For example, it was introduced accidentally into Hungary from North America in the 1940’s.) Hosts include nearly all shade, fruit, and ornamental trees except conifers. In the USA, at least 88 species of trees are hosts for these insects, while in Europe at least 230 species are impacted. In the past history of this pest, it was once thought that the fall webworm was a two-species complex. It is now thought that H. cunea has two color morphs – one black headed and one red headed. These two color forms differ not only in the coloration of the caterpillars and the adults, but also in their behaviors. Caterpillars may go through at least 11 molts, each stage occurring within a silken web they produce over the host. When alarmed, all caterpillars in the group will move in unison in jerking motions that may be a mechanism for self-defense. Depending upon the location and climate, 1-4 generations of fall webworm can occur per year. Fall webworm adult moths lay eggs on the underside of the leaves of host plants in the spring. These eggs hatch in late June or early July depending on climate. Young larvae feed together in groups on the undersides of leaves, first skeletonizing the leaf and then enveloping other leaves and eventually entire branches within their webs. Webs are typically found on the terminal ends of branches. All caterpillar activity occurs within this tent, which becomes filled with leaf fragments, cast skins, and frass. Fully grown larvae then wander from the webs and pupate in protected areas such as the leaf litter where they will remain for the winter. Adult fall webworm moths emerge the following spring/early summer to start the cycle over again. 50+ species of parasites and 36+ species of predators are known to attack fall webworm in North America. Fall webworms typically do not cause extensive damage to their hosts. Nests may be an aesthetic issue for some. If in reach, small fall webworm webs may be pruned out of trees and shrubs and destroyed. Do not set fire to H. cunea webs when they are still attached to the host plant.

• Imported Willow Leaf Beetle: Plagiodera versicolora adult beetles overwinter near susceptible hosts. Adult beetles will chew holes and notches in the leaves of willow once they become available. Females lay yellow eggs in clusters on the undersides of leaves. Larvae are slug-like and bluish-green in color. They will feed in clusters and skeletonize the leaves. Adult imported willow leaf beetles are still very active in Boylston, MA as of 6/27/2023 on their namesake host plants. Most plants can tolerate the feeding from this insect, and foliage will appear brown. Repeated yearly feeding can be an issue, in which case management of the young larvae may be necessary. Take care with treatment in areas near water.

Check out Episode 4 of InsectXaminer to see the imported willow leaf beetle in action.

• Magnolia Scale: Neolecanium cornuparvum is distributed throughout the eastern United States. Host plants include: Magnolia stellata (star Magnolia), M. acuminata (cucumber magnolia), M. lilliflora ‘Nigra’ (lily magnolia; formerly M. quinquepeta), and M. soulangeana (Chinese magnolia). Other species may be hosts for this scale but attacked to a lesser degree. M. grandiflora (southern magnolia) may be such an example.

Mature individuals settle on a location on branches and twigs, then insert piercing-sucking mouthparts to feed. The insects feed on plant fluids and excrete large amounts of a sugary substance known as honeydew. Sooty mold, often black in color, will then grow on the honeydew that has coated branches and leaves. Repeated, heavy infestations can result in branch dieback and at times, death of the plant. Honeydew may also be very attractive to ants, wasps, and hornets. The magnolia scale overwinters as a young nymph (immature stage) which is elliptical in shape, mostly a dark-slate gray, except for a median ridge that is red/brown in color. These overwintering nymphs may be found on the undersides of 1st and 2nd year old twigs. The first molt (shedding of the exoskeleton to allow growth) can occur by late April or May in parts of this insect’s range and the second molt will occur in early June. At that time, the immature scales have turned a deep purple color. Stems of the host plant may appear purple in color and thickened – but this is a coating of nymphal magnolia scales, not the stem itself. Eventually, these immature scales secrete a white layer of wax over their bodies, looking as if they have been rolled in powdered sugar. By August, the adult female scale is fully developed, elliptical and convex in shape, and ranging from a pinkish-orange to a dark brown color. Adult females may also be covered in a white, waxy coating. By that time, the females produce nymphs (living young; eggs are not “laid”) that wander the host before settling on the newest twigs to overwinter. In the Northeastern United States, this scale insect has a single generation per year.

• Two-Spotted Spider Mite: Tetranychus urticae is a “warm-season” mite that loves hot and dry weather, which may favor the quick reproduction and build-up of this pest. Management should seek to preserve beneficial predatory mites. Monitor susceptible hosts (elm, maple, redbud, ash, black locust, tuliptree, and many deciduous shrubs) for increasing numbers of these mites until mid-August. Mites will be found on the undersides of leaves and cause stippling of the foliage.
• Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. By 2008, viburnum leaf beetle was considered to be present throughout all of Massachusetts. Larvae are present and feeding on plants from approximately late April to early May until they pupate sometime in June. Much damage from viburnum leaf beetle feeding is currently apparent in areas of Massachusetts where this insect has become established. See photo courtesy of Tom Ingersoll from 6/5/2023. Adult beetles emerge from pupation by approximately mid-July and will also feed on host plant leaves, mate, and lay eggs at the ends of host plant twigs where they will overwinter. This beetle feeds exclusively on many different species of viburnum, which includes, but is not limited to, susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum, and V. rafinesquianum. Some viburnum have been observed to have varying levels of resistance to this insect, including but not limited to V. bodnantense, V. carlesii, V. davidii, V. plicatum, V. rhytidophyllum, V. setigerum, and V. sieboldii. More information about viburnum leaf beetle may be found at http://www.hort.cornell.edu/vlb/ and at https://ag.umass.edu/landscape/fact-sheets/viburnum-leaf-beetle.
• Yellow Poplar Weevil: Odontopus calceatus is also known as the sassafras weevil, the magnolia leafminer, or the tulip tree leafminer. This insect, as all of these common names suggest, feeds on yellow poplar (tulip tree; Liriodendron tulipifera), sassafras (Sassafras albidum), magnolia (Magnolia spp.), as well as bay laurel (Laurus nobilis). This insect is native to much of the eastern United States. Both the larvae and the adults of the yellow poplar weevil will feed on its hosts. Adults feed on the leaves and buds while the larvae mine the leaves. Adult feeding causes irregular holes to form in the leaves. Yellow poplar weevils overwinter as adults in sheltered areas, such as the leaf litter, around their hosts. In the early spring, they initiate feeding on the buds and newly opening leaves of the host plant. By May, they lay eggs in the midrib of the leaves on leaf undersides. Eggs will hatch and the larvae mine the leaves, creating blotch-like mines. This mining begins at the tip (point) of the leaf on tulip tree and Magnolia grandiflora hosts. Yellow poplar weevil larvae are white, legless, and approximately 2 mm long. Up to 9 larvae have been recorded in a single blotch mine. Larvae are mostly observed in late May and June. Pupation occurs in the leaf mines and adults of the new generation emerge to feed on leaves. Adults have been observed feeding as late as August in the southern portions of its range in the US (ex. Mississippi). Adult weevils may seek indoor shelters (such as homes) for overwintering protection. Feeding damage from this insect is not often reported as of economic importance, however in the southern parts of its range outbreaks have occasionally occurred (Johnson and Lyon, 1991). Natural enemies of the yellow poplar weevil have been reported, particularly hymenopteran parasitoids. Five species (Heterolaccus hunteri, Habrocytus piercei, Horismenus fraternus, Zagrammosoma multilineatum, and Scambus hispae) have been reported to kill 50% of yellow poplar weevil pupae (Burns and Gibson, 1968).

Concerned that you may have found an invasive insect or suspicious damage caused by one? Need to report a pest sighting? If so, please visit the Massachusetts Introduced Pests Outreach Project.

Reported by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program

Landscape Weeds

For identification of weed species noted below, refer to UMass Extension's Weed Herbarium: https://ag.umass.edu/weedid

At this point in the season, summer annual weeds in landscape beds have become larger due to the warm weather and adequate amounts of rainfall. Treating them with a non-selective herbicide will result in unsightly dead vegetation, so hand weeding may be necessary. Consider physical removal, followed by a fresh mulch layer. A fresh layer of mulch will cover any plants not removed as well as provide protection against the germination of winter annual weeds later in the season.

Monitor mulches in landscape beds as some of the recent torrential rainfall events may have moved mulch and left bare soil. Consider re-mulching these areas.

Do not attempt to control Japanese knotweed, as herbicide applications are not effective when applied during this part of the growing season. As we approach the time for herbicide application, however, there is one thing you should be thinking about: since knotweed is commonly found in wet areas or near streams, rivers, or wetlands, its management in Massachusetts may invoke 310 CMR 10.00, which is the Massachusetts Wetlands Protection Act. 310 CMR 10.00 regulates all activities in resource areas identified in the act. If a knotweed management project is being considered, now is the time to begin work with the Conservation Commission in the municipality to determine to what extent the Act might impact your project. For states other than Massachusetts, you should seek information about that state’s regulation for activities near water. Application timing and herbicide product selection will be provided when the application window for effective control arrives later in the season.

Poison ivy is in fruit and should be treated now. Glyphosate or triclopyr are the best herbicides for poison ivy control. Triclopyr products should be selected over glyphosate products in areas where grasses need to be saved. Contact (Scythe^TM, Reward^TM) or the non-chemical/organic herbicide products will provide “burndown” activity only and will not adequately control poison ivy. REMEMBER, the oil in poison ivy known as urushiol is still active in the plant after the plant is dead and can cause contact dermatitis. Urushiol occurs in all parts of the plant, including the roots.

Reported by Randy Prostak, Weed Specialist, UMass Extension Landscape, Nursery, & Urban Forestry Program

Odds and Ends

New UMass Extension Freeze Event Impacts Survey! 

The freeze events of February 3-4 and May 18, 2023, had significant impacts on agricultural sectors including tree fruits, berries, vegetables, ornamentals, and others. Now that losses are evident for most crops, UMass Extension and our partners* hope to generate timely reporting on losses at the state and regional levels. If you produce agricultural crops (including nursery stock) and you experienced crop losses due to the February 3-4 deep freeze and/or the May 18th freeze, please report them by filling out this survey: https://umassamherst.co1.qualtrics.com/jfe/form/SV_b2BKrQXOUpV8aNg. The survey deadline is July 31.

This data will help document the extent of crop and economic losses and will inform the public and decision-makers who may be considering actions that would provide emergency funds to Massachusetts producers. Some growers may also receive insurance payments or be eligible for low-interest FSA loans or other USDA disaster programs. However, data from these programs will take many months to report, and may under-report losses in some sectors. Producers should also report losses to their local FSA office as soon as the extent of the damage can be assessed - this survey is not intended to take the place of reporting to FSA.

Your data and privacy will be protected. Please see details in the opening page of the survey and on the final page, where you may choose to provide and share contact information if you wish. No crop loss data at the individual farm level will be shared.

*Partners include: USDA Farm Services Agency, USDA Risk Management Agency, MA Department of Agricultural Resources, MA Farm Bureau Federation, MA Food System Collaborative, MA Fruit Growers’ Association, New England Vegetable and Berry Growers Association, Community Involved in Sustaining Agriculture (CISA), Southeast MA Agricultural Partnership (SEMAP), and Berkshire Grown.

If you have questions about this survey, please contact cclay@umext.umass.edu.

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Additional Resources

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For a complete listing of landscape, nursery, and urban forestry program upcoming events, see our calendar at https://ag.umass.edu/landscape/upcoming-events.

For commercial growers of greenhouse crops and flowers - Check out UMass Extension's Greenhouse Update website.

For professional turf managers - Check out our Turf Management Updates.

For home gardeners and garden retailers - Check out our home lawn and garden resources. 

Diagnostic Services

UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see the Plant Diagnostic Laboratory web site.

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of the University of Massachusetts at Amherst. Testing services are available to all. The lab provides test results and recommendations that lead to the wise and economical use of soils and soil amendments. For more information, including current turn-around times, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. The lab is currently accepting orders for Routine Soil Analysis (including optional Organic Matter, Soluble Salts, and Nitrate testing), Particle Size Analysis, Pre-Sidedress Nitrate (PSNT), Total Sorbed Metals, and Soilless Media (no other types of soil analyses available at this time). Check for current turnaround time. Please plan for the fact that date of receipt in the lab is affected by weekends, holidays, shipping time, and time for UMass Campus Mail to deliver samples to the lab.

Tick Testing - The UMass Center for Agriculture, Food, and the Environment provides a list of potential tick identification and testing options at: https://ag.umass.edu/resources/tick-testing-resources.

Acknowledgements: UMass Extension gratefully acknowledges the support of the following funding sources for the production of the Landscape Message –

• The Massachusetts Nursery and Landscape Association Fund
• The Massachusetts Department of Conservation and Recreation, Award #ISADCR28219926UMA23A
• Stakeholders like you! The Landscape Message is partially supported by educational program user fees.