Landscape Message: July 22, 2022

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.

The Landscape Message will be updated twice in August. The next message will be posted on August 5. 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 20, 2022. Total accumulated growing degree days (GDD) represent the heating units above a 50º F baseline temperature collected via regional NEWA stations (http://newa.cornell.edu) for the 2022 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	GDD		Soil Temp (°F at 4" depth)		Precipitation (2-Week Gain)	Time/Date of Readings
	2-Week Gain	2022 Total	Sun	Shade
CAPE	329	1211	76	71	0	12:00 PM 7/20
SOUTHEAST	334.5	1327.5	86	73	0.15	3:00 PM 7/20
NORTH SHORE	340	1262	79	67	0.56	1:00 PM 7/20
EAST	365	1457	77	73	0.43	5:00 PM 7/20
METRO	334	1354	71	68	0.87	5:30 AM 7/20
CENTRAL	343	1356	80	71	1.13	1:45 PM 7/20
PIONEER VALLEY	332.5	1375	76	73	2.16	12:00 PM 7/20
BERKSHIRES	281	1111	73	68	2.01	6:00 AM 7/20
AVERAGE	332	1306.5	77	71	0.91	_
* = information not available

As of 7/19, only the western edge of Berkshire County is "Abnormally Dry", the rest of MA is in a D1 "Moderate Drought" or D2 Severe Drought status.  Massachusetts | U.S. Drought Monitor (unl.edu)                                

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.
Clethra alnifolia (summersweet clethra)	Begin	Begin	*	*	*	*	*	*
Hibiscus syriacus (rose-of-Sharon)	Begin	Full	Full	Full	Full	Full	Full	Begin/Full
Buddleia davidii (butterfly bush)	Begin	Full	Full	Full	Full	Full	Full	*
Campsis radicans (trumpet vine)	Full	End	Full	Full	Full	Full	Full	Begin/Full
Hydrangea paniculata (panicle hydrangea)	Full	Begin/Full	Full	Full	Full	Full	Begin/Full	Begin
Koelreuteria paniculata (goldenrain tree)	Full	*	Full	Full	Full/End	Full	Full	Full
Lythrum salicaria (purple loosestrife)	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 July 6 thru July 20 was 72°F with a low of 52°F on July 10 and a high of 90°F on July 20. For the past week, highs have been in the 80s and lows in the 60s and 70s, the prior week temperatures were more comfortable with highs in the 70s and lows in the 50s and 60s. Precipitation has been lacking for the period, with zero precipitation recorded in Barnstable. The total for July so far is 1/3 of an inch following two months that were also on the dry side. Soils are so dry, many towns/villages have mandatory water restrictions in place. The effects of low soil moisture are readily visible in managed landscapes and natural landscapes. Many herbaceous and woody plants are showing signs of wilting and woody species susceptible to scorch such as dogwood and some maples are scorching. Unirrigated lawns are crispy. Some herbaceous plants seen in bloom include shasta daisy (Leucanthemum x superbum), daylily (Hemerocallis spp.), montbretia (Crocosmia x crocosmiiflora), blazing star (Liatris spicata), purple coneflower (Echinacea purpurea), black-eyed susan (Rudbeckia hirta) and plantain lily (Hosta spp.). Some woody plants seen in bloom include hydrangeas (Hydrangea spp.), New Jersey tea (Ceanothus americanus), mimosa (Albizia julibrissin) and sourwood (Oxydendrum arboreum).

Pests/Problems: Pine tip moth damage is widespread on pitch pine (Pinus rigida), this is the third year in a row which pine tip moth has been widespread. Some past gypsy moth damage was observed in the mid-Cape area, fall tent caterpillar is active and seen on tupelo (Nyssa sylvatica), Japanese, Oriental and Asiatic beetles are still active, unidentified caterpillar damage on bearberry, rose slug sawfly damage was observed on rose, viburnum leaf beetle damage on viburnum, leaf miner damage on daylily, hibiscus sawfly damage on hardy hibiscus and turpentine beetle activity on pitch pine. Disease symptoms observed during the period include pear trellis rust on Callery pear, beech leaf disease on beech, cercospora leaf spot on hydrangea, anthracnose on river birch, branch dieback and tip dieback on Leyland cypress, powdery mildew on phlox, asters, monarda, smoke bush, dogwood and others, brown rot on ornamental cherry and black spot on rose. Weeds and invasive plants in bloom include birdsfoot trefoil (Lotus corniculatus), sheep’s bit (Jasione montana), fleabane (Erigeron annuus), spotted knapweed (Centaurea stoebe), pokeweed (Phytolacca americana), lambsquarters (Chenopodium album), and spotted spurge (Euphorbia maculata).

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Southeast Region (Dighton)

General Conditions: It's hot, hot, hot. Day temperatures have ranged from 80°F to 100°F while nights have been as low as 48°F. The few passing showers on 7/10, 7/12 and 7/14 were very localized and all too brief. As towns have imposed watering bans, lawns have become patches of brown, gray and crabgrass. Herbaceous plants wilt at midday. Woody plants are shedding leaves and turning color in senescence. Ruby throated hummingbirds, blue mud daubers, golden digger wasps, sweat bees, monarch butterflies and hummingbird moths can be seen among the other pollinators greadily seeking nectar. Among the plants currently in flower are: Aesculus parviflora (bottlebrush buckeye), Albizia julibrissin (mimosa), Asclepias incarnata (swamp milkweed), Daucus carota (Queen Anne's lace), Campanula rapunculoides (creeping harebell), Coreopsis verticillata (tickseed), Echinacea spp. (coneflower), Gaillardia spp. (blanket flower), Hosta spp. (plantain lily), Hydrangea macrophylla (big leaf hydrangea), Liatris spp. (blazing star), Lilium tigrinum (tiger lily), Lysimachia clethroides (gooseneck loosestrife), Monarda spp. (bee balm), Oenothera biennis (evening primrose), Phlox paniculata (garden phlox), Rhus typhina (staghorn sumac), Rudbeckia spp. (black-eyed Susan), Salvia yangii (Russian sage), Solidago juncea (early goldenrod), Tanacetum vulgare (tansy), and Vitex agnus-castus (chaste tree).

Pests/Problems: Heat and drought remain the most serious problems threatening both plants and animals. The very invasive, tough to remove Japanese knotweed, Reynoutria japonica, is in bloom along moist roadsides, streams and rivers everywhere.

North Shore (Beverly)

General Conditions: The past two-week period was hot and humid except for a few days in the beginning. Temperatures of 90℉ and above were recorded on three days and a heat advisory has been posted in the area for the last two days. Temperatures are in the low to mid-90s with high humidity. Daytime temperatures were in the mid-70s to low 90s and nighttime temperatures were mostly in the low 60s to low 70s. The average daily temperature for this period was 73℉ with the maximum temperature of 91℉ recorded on July 19 & 20 and the minimum temperature of 53℉ recorded on July 10. According to the US Drought Monitor the area is in severe drought. (See link above, at the bottom of the Environmental Data table.) During this reporting period, a few fast moving storms passed through and dropped approximately 0.56 inches of much needed precipitation. However, this small amount of precipitation is not enough to get the area out of drought. Woody plants seen in bloom include mimosa (Albizia julibrissin), oakleaf hydrangea (Hydrangea quercifolia), smooth leaf hydrangea (Hydrangea arborescens), summer blooming spiraea (Spiraea japonica), tree false spirea (Sorbaria arborea), mountain camellia (Stewartia ovata), cut-leaf chaste tree (Vitex negundo), and sourwood (Oxydendrum arboreum). Herbaceous plants seen in bloom include: black-eyed Susan (Rudbeckia hirta), purple coneflower (Echinacea purpurea), bush cinquefoil (Potentilla fruticans), cranesbill (Geranium spp.), bee balm (Monarda spp.), Turk's cap lily (Lilium superbum), milkweed (Asclepias spp.), montbretia (Crocosmia x crocosmiiflora), shasta daisy (Leucanthemum x superbum), yarrow (Achillea millefolium), hostas (Hosta spp.), sedums (Sedum spp.), lamb’s ear (Stachys officinalis), tall meadow rue (Thalictrum rochebrunianum), false goat’s beard (Astilbe spp.), summer flowering roses (Rosa spp.), water lily (Nymphaea odorata) and an assortment of annual plants.

Pests/Problems: Powdery mildew was observed on susceptible lilac varieties and on bee balm. Crabgrass, yellow nutsedge and other weeds are thriving due to warm temperatures and recent precipitation. Deer browsing damage was observed on some perennials and shrubs. Grass on lawns that are on sunny drought locations are still struggling with water stress due to high temperatures and inadequate precipitation. Ticks and mosquitos are very active. Protect yourself with effective insect repellent before going out to the woods and check your body for ticks after you return.

East Region (Boston)

General Conditions: The summer continues to be hot and dry. Temperatures averaged 85℉ over the past two weeks. Tuesday the 19th reached 90℉, the first in a predicted heat wave of up to 5 consecutive days in the 90’s. We received 0.43 inches of precipitation over this reporting period. The one beneficial rain event of 0.25 inches fell on the evening of July 18th. Summer flowering trees in bloom include Albizia julibrissin (mimosa, silk tree), ​​​​​​​Koelreuteria paniculata (golden rain tree), Oxydendrum arboreum (sourwood) and Stewartia pseudocamellia (stewartia). The shade tolerant Aesculus parviflora (bottlebrush buckeye) is in full bloom. The carefree Queen Anne’s lace (Daucus carota) and chicory (Cichorium intybus) are flowering along roadsides.​​​​​​​
​​​​​​​Pests/Problems: Dry soil conditions are a major concern. We have received only 0.78 inches of precipitation the entire month of July and the drought monitor status here is D2 - "Severe Drought". Many Amelanchier spp. (shadbush), Betula spp. (birches) and Malus spp. (crabapples) are experiencing early fall color and leaf drop. Unmanaged Cyperus esculentus (yellow nutsedge) is flowering. Some Phytolacca americana (pokeweed) is five feet tall, flowering and forming fruit.

Metro West (Acton)

General Conditions: We are in the full swing of summer, and we are feeling it now! As I begin to write this report on Tuesday afternoon, the thermometer reads 91°F and it is the first day of our first heat wave for the summer. Forecasters are predicting at least 5 more days, until Sunday, of temperatures in the 90s. For July, the monthly average precipitation is 3.95”, and as of the 19th, a total of 1.22” of rain has been recorded. Observed in some stage of bloom this past week were the following woody plants: Aesculus parviflora (bottlebrush buckeye), Albizia julibrissin (silk tree), Hydrangea arborescens (smooth hydrangea), H. quercifolia (oakleaf hydrangea), Oxydendrum arboreum (sourwood), and Potentilla fruiticosa (potentilla). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Asclepias syriaca (common milkweed), A. tuberosa (butterfly weed), Astilbe spp. (false spirea), Cichorium intybus (chicory), Daucus carota (Queen Anne's lace), Echinacea purpurea (coneflower), Hosta spp. (plantain lily), Leucanthemum sp. (shasta daisy), Lilium spp. (lily), Lysimachia clethroides (gooseneck loosestrife), Monarda didyma (scarlet beebalm), Patrinia gibbosa (patrinia), Perovskia atriplicifolia (Russian sage), Phlox paniculata (garden phlox), Rudbeckia hirta (black eyed Susan), Senna marilandica (wild senna), and Veronicastrum virginicum (culver’s root).

Pests/Problems: The lack of any substantial and steady rain continues to be a concern for our trees and shrubs in the landscape, especially compounded with the hot and humid weather. As of July 12th, the Massachusetts Office of Energy and Environmental Affairs declared that over 90% of the State was experiencing drought conditions. Level D2 – "Severe Drought" - has been declared for this area while most of Massachusetts including the Cape and the Islands, have a D1 - "Moderate Drought" staus. Setting seed and quite visible is Ailanthus altissima (tree of heaven), an invasive tree that is now highly visible and showy because its seeds (samaras) are reddish in color, are plentiful and grow in large clusters. Look for it growing along roadsides and in parking lots and medians. Also observed in the landscape these past two weeks was leafroller activity on Clethra alnifolia (summersweet).

Central Region (Boylston)

General Conditions: It’s hot and dry. For this reporting period, high temperatures reached 80°F every day but one, when the high temperature maxed out at 77°F. Comfortable sleeping weather is gone, as humidity levels have remained high and overnight temperatures were well into the 70’s nearly every day. There is plenty in bloom across the landscape. Our summer flowering hydrangea (Hydrangea macrophylla, H. serrata, H. paniculata, H. quercifolia, and H. arborescens) are all coming into their own. Stewartia pseudocamellia (Japanese or Korean stewartia) is open and will continue blooming for several weeks. Its distant cousin, Franklinia alatamaha (the Franklin tree), a small flowering tree also in the tea family, is opening and will continue to bloom as late as November. Many native asters, goldenrods, and other summer blooming perennials are showing color as well, but Liatris spicata (blazing star) is stealing the show with spikes of bright purple flowers.

Pests/Problems: The latest report from the US Drought Monitor on July 19 shows the northern part of the Central Region has moved into severe drought status. The bulk of the region is in moderate drought and signs of distress across the landscape are apparent. Established trees and shrubs are dropping foliage, even irrigated lawns are browning, and the need for substantial precipitation is growing daily as we work our way through the 5th month in a row with less than average precipitation. Other than drought impacts, we have seen few if any insect and disease issues across the landscape. Not even any powdery mildew!.

Pioneer Valley Region (Amherst)

General Conditions: After a mostly mild start to summer in the Pioneer Valley, the dog days are here. High heat and humidity have descended on the entire region (much of the U.S. for that matter), with the year’s first heat wave predicted from 7/20 to possibly 7/24 (forecast at the time of writing). Four rain events occurred over the past two weeks, with scattered showers and thunderstorms occurring on 7/12, 7/13–14 and 7/18–19. The southern half of the tri-counties fared well from the storms, with accumulations ranging from 2.16” (Easthampton & Westfield), 2.67” (Chicopee) and 2.74” (Belchertown). As a result, upper soil moisture was sufficient prior to the heat wave. Unfortunately, accumulations in the northern half of the valley were far less plentiful, with accumulations varying from 0.26” (Ashfield), 0.56” (Orange), and 0.77” (South Deerfield) to 1.02” (Deerfield). All of Franklin, Hampshire and Hampden Counties remain in D1 (moderate) drought classification according to the most recent U.S. Drought Monitor survey. However, as noted above and corroborated by the NRCC, the southern Connecticut Valley did receive above-average rainfall during the first half of July. Given the record-breaking rainfall in 2021, lower soil horizons may be providing moisture for trees with deeper rooting systems. This will hopefully allow them to buffer against the drying upper soil horizons. Despite the dry conditions, some trees such as red maple and eastern hemlock continue to push new growth. Fewer landscape trees and shrubs are now in bloom and herbaceous perennials and annuals are taking center stage in the landscape. Asiatic lily, daylily, astilbe, coneflower, black-eyed Susan, bee balm, Russian sage and milkweed, among many others, are in full bloom. Bees and other pollinators are working hard during this peak of the wildflower season. Monarch butterflies continue to emerge along with a wide assortment of other butterflies and moths. With small moths, it’s nearly impossible to distinguish which are benign and which are tree and shrub pests. It can be challenging at this point in the growing season to decide whether to plant a tree or shrub or wait until cooler conditions in early fall. Soil temperatures are significantly cooler than potting media temperatures and plants in the ground require less frequent watering compared to those in pots. The decision may hinge on how much effort is required to reorient and disentangle the roots. If planting will require significant injury to the root system, to uncover the flare and reorient a badly tangled root system, it may be best to wait for cooler conditions.

Pests/Problems: Beech leaf disease, caused by the foliar nematode Litylenchus crenatae ssp. mccanii, was found on an American beech (Fagus grandifolia) in West Hatfield by Kristina Bezanson, UMass Lecturer in Arboriculture and Urban Forestry. Confirmed cases in the Connecticut Valley have been uncommon to date, but the disease has been found on scattered trees throughout western Mass. Drought stress will be a major concern for the immediate future on susceptible trees and shrubs, especially in Franklin and northern Hampshire Counties. This area did not receive as much rainfall from the recent storms as the southern half of the valley. Interior canopy leaf yellowing and shedding on Katsura trees was observed on the Umass campus. Marginal leaf scorch is also developing on Stewartia, a sure sign of warm and dry weather. Needle shedding on eastern hemlocks in droughty soils has also been seen. Continue to closely scout trees and shrubs for symptoms and signs of disease and insects. Insect infestations may go unnoticed from a distance but are obvious when plants are viewed from a close distance. Many trees and shrubs are showing the early signs of wear and tear that develops over the course of a long growing season. Leaf spots, blotches, marginal leaf scorch, browning needles and branch dieback can be found on a variety of hardwoods and conifers. Turfgrasses range from green and lush (irrigated) to brown and unsightly (unirrigated in full sun). Invasive scarab beetles are feeding on various landscape trees, shrubs, perennials and vegetable crops. Wasp and hornet ground nests should be visible at this time.

Berkshire Region (Great Barrington)

General Conditions: The heat has arrived! After some very comfortable temperatures since the beginning of summer, energy sapping heat has settled in for the time being. Temperature ranges over the past two weeks, i.e. July 6 – 20 varied a bit among the 3 stations reporting on the NEWA site. North Adams experienced a high of 90°F (up to 3:00 pm) on July 20 and a low of 46°F on the 10th; Pittsfield had a high of 89°F on the 20th and a low of 48°F on the 11th; Richmond recorded a high of 88°F on the 20th and a low of 48°F on the 11th. Since this report is being prepared in mid-afternoon of the 20th, those high readings may be even a bit more. While the Berkshires are not experiencing the same drought conditions as counties to the east, it still falls in the category of “mild drought”. However, total rainfall for the scouting period did vary quite a bit at all the reporting stations: North Adams (1.52 inches), Pittsfield (0.94 inches), Richmond (1.48 inches), and West Stockbridge (2.01 inches). At this site in West Stockbridge, soils are currently moist but with the heat and breezes, evaporation is quick and soil dries quickly as well. One sign of the somewhat dry conditions is the slower growth rate of non-irrigated turfgrass. The most serious weather event of the past two weeks took place on the evening of Tuesday, July 12th when a microburst hit the town of Lenox, bringing down numerous trees and power lines, and resulted in one fatality. The National Weather Service estimated straight line winds up to 85 mph. Interestingly, it was just about one year ago that a similar microburst traveled the same path through Lenox and caused similar damage but no deaths. Growth of herbaceous perennials continues at a steady pace and ‘tis the season for the large, showy blooms of daylilies and Asiatic lilies. Most of the tree and shrub species that suffered severe defoliation by the spongy moth caterpillars are slowly recovering and most are putting out a new set of foliage. Of course, this does consume much of the stored energy of these plants and does somewhat weaken them. Their overall health will depend upon what happens next year as far as defoliation is concerned.

Pests/Problems: Japanese beetles have replaced spongy moth caterpillars as the primary culprits in damaging plants in landscapes and gardens, including vegetable gardens. Most notable is damage to roses, many of which were previously defoliated by the caterpillars and now their regenerated leaves are being skeletonized by the beetles. As for the spongy moths, I may have been overly optimistic about their future after observing huge numbers of the caterpillars dying from the virus and fungi infections. Over the past two weeks, a very large number of male moths have been fluttering about. On the other hand, not many of the flightless females have been seen awaiting the males on the trunks of trees. Nevertheless, there are new egg masses visible, but the numbers vary from one area to another. Aphids and whiteflies are common on many herbaceous plants. Other than powdery mildew, few diseases have been observed. Mosquitoes and deer tick numbers remain high. Iron chlorosis symptoms were found on magnolia. This problem, iron deficiency, is not uncommon in many parts of the Berkshires due to high pH of soils here, a situation related to the prominence of limestone bedrock. It is also not uncommon to see these symptoms on the leaves of acid-loving shrubs planted near concrete foundations. One way to avoid these problems is to simply test soils prior to planting and select plants adapted to high pH soils.

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

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

• Leaf blotch and stem cankering, caused by Botryosphaeria s.l., on drooping laurel (Leucothoe fontanesiana). The plants are approximately 15-years-old and reside in a historical landscape underneath a canopy of eastern hemlock. The site is fully shaded and some supplemental water is received from lawn sprinklers. The plants have been hand-pruned as needed and no prior chemical treatments have been recorded. The submitted foliage has scattered, dark leaf spots and blotches while the stems had blackened cankers with discolored vascular tissue. While foliar infections by Botryosphaeria s.l. are uncommon, they can occur on broadleaved evergreens like Leucothoe.
• Stem and branch cankering on copper beech (Fagus sylvatica) caused by Asterosporium and Phomopsis. The tree is very old, believed to be ~150-years-old, and resides in the front lawn of a residential property surrounded by a U-shaped driveway. The site is characterized by full sun with soils that are a mix of sand and loam. A large row of pines nearby that had been shading the tree was removed in the past ten years. Since 2020, the tree has exhibited canopy dieback that intensified this year. There were no symptoms of beech leaf disease from the submitted sample but the tree is in a community with several documented cases. The foliage was undersized and small stems and branches were infected by two cankering pathogens. Asterosporium may be more common on beech than is fully appreciated. It can infect large branches, resulting in cracking and sloughing bark as the phloem is killed. The dark-colored spores are produced in abundance on the dead bark, creating a black, sooty appearance to the cankered sites.
• Phyllosticta leaf blotch (Phyllosticta hamamelidis) on Arnold Promise witch-hazel (Hamamelis x intermedia 'Arnold Promise'). The shrub is ~20-years-old and was planted 14 years ago. The site includes heavy shade, soils are droughty, and no supplemental water is provided. In June, interior canopy leaves started browning and the plant has an overall thin appearance. Phyllosticta leaf blotch starts out as scattered spots and blotches but can quickly consume the entire leaf when conditions are ideal. Heavy shade favors the pathogen and infections often initiate on interior portions of the canopy. Spring-flowering witch-hazel hybrids appear to be more susceptible to the disease, in comparison to native H. virginiana. When siting the hybrids, ensure that plants will receive full sun to reduce disease pressure.
• Glyphosate exposure on California privet (Ligustrum ovalifolium). The plant is roughly 15-years-old and has been present at the site for 12 years. The setting includes a mixture of sun and shade and the plant is provided with drip irrigation. The submitted branch segments had obvious symptoms of glyphosate exposure, which included stunted and tufted masses of foliage (witches’ brooming) along the scattered stem distortion (see photo). A sample from this same plant was previously submitted in 2020. At that time, the plant was suffering from Alternaria leaf spot, Phomopsis stem cankering and an oystershell scale infestation. Non-lethal exposure to glyphosate can make plants susceptible to various environmental stresses and disease. However, if the exposure stops, the plant has a good chance of recovery if regular care is maintained.
• Phenoxy herbicide exposure on a two-needle pine (possibly a Pinus sylvestris). The tree is approximately 15-years-old and has been present at the site for eight years. It receives full sun in droughty, well-drained soils between a residential home and driveway but supplemental water is provided via drip irrigation. The submitted sample had highly distorted and stunted needles that are typical of exposure to phenoxy herbicides. Spray drift was the most likely source of exposure. Plants can resume normal growth after non-lethal exposure but it may take several years for the plant to regain full vigor.

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

Insects

An Update about Neonicotinoid Use in Massachusetts:

Beginning July 1, 2022 systemic insecticide active ingredients known as neonicotinoids have become state restricted use for tree and shrub uses in Massachusetts. If an individual works in the commercial industry (landscapers, arborists, etc.), then a Commercial Certification License is needed. (Example: Category 36 Commercial Certification License, Shade Trees & Ornamentals.) Someone can use a state or federal restricted use pesticide if they have a Commercial Applicators License as long as they are working under the direct supervision of someone with a Commercial Certification. Unlicensed or uncertified individuals will no longer be able to apply neonicotinoids to manage insect pests of trees and shrubs in Massachusetts.

More information is available, here: https://www.mass.gov/service-details/pesticide-newsupdates

Helpful Information from Taryn LaScola-Miner, Director, Crop and Pest Services Division of the MA Department of Agricultural Resources:

“As you know, products that contain neonicotinoids and have certain use patterns will have a classification change from General Use to Restricted Use on July 1, 2022. In order to help inform the manufacturers, dealers, sellers and applicators of which products will be changing from general use to restricted use, the Department has created the list of neonicotinoid products that currently are and will become restricted use beginning July 1st. You may find the list at the link below. Please note that this list is subject to change.

Additionally, MDAR is anticipating that there will be more of a need for companies to follow the Direct Supervision regulations with this change. Therefore, MDAR has updated its Direct Supervision Frequently Asked Questions document as well.

Although an email will be sent to all licensed applicators within the next few weeks as a final reminder of the change, please pass this information along to your members and customers as an effort to make this transition as smooth as possible. If you have any questions, please let me know. Thank you!”

List of Neonicotinoid Products: https://www.mass.gov/doc/list-of-neonicotinoid-pesticides/download

Direct Supervision Frequently Asked Questions: https://www.mass.gov/doc/direct-supervision-frequently-asked-questions-faq/download

 

Interesting Insects Reported Recently:

• Purple Spotted Lily Aphid: Macrosiphum lilii is an aphid that has been collected from Asiatic lilies. They are relatively large/noticeable aphids that tend to be pale yellow in color or yellow-orange with long black antennae and cornicles. The most noticeable marking on the aphid (as the common name suggests) is a purple spot found at the top of the abdomen. The exact timing and life cycle of this species is not fully understood. Females give birth to other females during the growing season. This generation is capable of developing into wingless and winged adults. In the fall, sexual reproduction may occur. As with other aphids, they use piercing-sucking mouthparts to remove host plant fluids and excrete large amounts of sugary liquid waste in the form of honeydew. Sooty mold may then grow on the honeydew. Aphids have many natural enemies such as parasitic wasps, lady beetles, syrphid flies, and others. More information about this species may be found here: https://content.ces.ncsu.edu/purplespotted-lily-aphid .

 

Insects and Other Arthropods

• Mosquitoes: The Massachusetts Department of Public Health (DPH) announced on 7/13/2022 that West Nile virus (WNV) had been detected in mosquitoes in Massachusetts for the first time in 2022. The presence of WNV was confirmed by the Massachusetts State Public Health Laboratory in a mosquito sample collected July 11 in the town of Easton, MA in Bristol County. More information about this detection is available here: https://www.mass.gov/news/state-public-health-officials-announce-seasons-first-west-nile-virus-positive-mosquito-sample-3

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). For local risk levels of WNV and EEE based on state sampling, visit: https://www.mass.gov/info-details/massachusetts-arbovirus-update.  

For more information about mosquitoes in Massachusetts, visit: https://www.mass.gov/service-details/mosquitoes-in-massachusetts

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.

For more information about mosquito repellents, visit: https://www.mass.gov/service-details/mosquito-repellents and https://www.cdc.gov/mosquitoes/mosquito-bites/prevent-mosquito-bites.html .

• 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 will lay 1,500+ eggs in the forest leaf litter beginning around Memorial Day (late May). Larval and nymphal deer ticks may be encountered at this time. Larvae are encountered in New England from roughly May through November, with peak risk reported in August. Nymphs are encountered from April through July with a peak risk reported in June in New England. Nymphs may also be encountered again in October and November. For images of all deer tick life stages, along with an outline of the diseases they carry, visit: 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://web.uri.edu/tickencounter/prevention/protect-yourself/

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

• 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 Asian giant hornet (Vespa mandarinia). The European hornet is known to Massachusetts, but the Asian giant hornet is not. If you are concerned that you have found or photographed an Asian giant hornet, please report it here: https://massnrc.org/pests/report.aspx . A helpful ID tool, although developed for Texas by the USDA, depicts common look-a-like species that we also have in MA that can be confused for the Asian giant hornet and is found here: https://agrilife.org/lubbock/files/2020/05/Asian_Giant_Hornet_Look-alikes_101_Xanthe_Shirley.pdf . 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.

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

Invasive Insects & Other Organisms Update:

• Spongy Moth: Lymantria dispar activity in parts of Berkshire County has been heightened this year. Many areas have experienced defoliation and large numbers of caterpillars. The good news is, spongy moth caterpillar activity for 2022 is coming to an end.​​​​​

More good news: activity from the NPV virus and the spongy moth caterpillar killing fungus, Entomophaga maimaiga, has been reported in Berkshire County! Fungus and virus killed caterpillars have been reported in Williamstown, MA (6/21/2022) and Sheffield, MA (6/16/2022). Fungus-killed caterpillars will appear shriveled and dried, typically hanging vertically in a straight line on the trunks and branches of their hosts, or other surfaces nearby. Virus killed caterpillars tend to droop in an inverted-V shape and are often moist/juicy in appearance. The fungus and virus will hopefully help reduce the population of spongy moths in Berkshire County for next year – although time will tell. Continue to monitor for pupation and emerging adult male and female moths who will mate and lay their tan, spongy egg masses. Overwintering egg masses will provide the population for next year, if caterpillars survive to pupate into adults in 2022.  

The bottom line: do not panic. The spongy moth (Lymantria dispar) has been in Massachusetts since the 1860’s and periodic outbreaks have occurred since then. Due to the fungus, virus, and other natural enemies, the populations will crash again.

Why did the common name for Lymantria dispar change recently? More information is available here: https://entsoc.org/news/press-releases/spongy-moth-approved-new-common-name-lymantria-dispar

To learn more about the life cycle and natural enemies of this insect, including the NPV virus and Entomophaga maimaiga, 

visit: https://ag.umass.edu/landscape/education-events/insectxaminer.

• 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.

Currently, the only established populations of spotted lanternfly in Massachusetts are in a small area in both Fitchburg and Shrewsbury, 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: https://massnrc.org/pests/slfreport.aspx . If you are living and working in the Fitchburg and Shrewsbury areas, please be vigilant and continue to report anything suspicious.

For More Information:

From UMass Extension:

Check out the InsectXaminer Episode about spotted lanternfly adults and egg masses! Available here: https://ag.umass.edu/landscape/education-events/insectxaminer

Fact Sheet: https://ag.umass.edu/landscape/fact-sheets/spotted-lanternfly

From the MA Department of Agricultural Resources:

Fact Sheet and Map of Locations in MA: https://massnrc.org/pests/pestFAQsheets/spottedlanternfly.html

• 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.

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 Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938.

To report an Asian longhorned beetle find online or compare it to common insect look-alikes, visit: http://massnrc.org/pests/albreport.aspx or https://www.aphis.usda.gov/pests-diseases/alb/report .

• Browntail Moth: Euproctis chrysorrhoea is an invasive insect originating from Europe and first detected in the US in Somerville, MA in 1897. Currently, browntail moth is limited to a small portion of eastern Massachusetts, particularly areas near the coast.  Report suspected browntail moth life stages here: https://massnrc.org/pests/pestreports.htm . Due to a persistent outbreak of this insect in Maine since approximately 2016, it is a good idea for us to again familiarize ourselves with this pest. (For more information and the latest updates about the status of this insect in Maine, visit: https://www.maine.gov/dacf/mfs/forest_health/invasive_threats/browntail_moth_info.htm .)

Caution: hairs found on the caterpillar and pupal life stages of this insect can cause a rash similar to poison ivy. Some individuals are very sensitive to browntail moth hairs and may also experience allergic reaction. The chance of interacting with browntail moth hairs increases between May and July, although they could be a problem at any time of year.

The larval or caterpillar stage of this insect is present from August until the following June (spending the winter in webs they create on the tips of host plant twigs). In the fall, groups of caterpillars are found creating webs around a tightly wrapped leaf (covered in bright white silk) where they will overwinter in groups of 25-400. These 2-4 inch long webs can be found on the ends of branches often on apple or red oak. As soon as leaves begin to open in the spring (usually by April), the caterpillars will crawl from their webs to feed on the new leaves. Caterpillars are fully grown around June and spin cocoons in which they pupate. These cocoons are also full of the irritating hairs and should be dealt with extreme caution. Adult moths emerge in July and females lay eggs on the undersides of leaves in masses of 200-400, covering them with hairs from their bodies. (Adults do not typically cause skin rashes.) Eggs hatch around August and September and larvae feed shortly before forming their overwintering webs.

The primary concern with this insect are the poisonous hairs found on the caterpillars. Contact with the caterpillar or its hairs can cause a rash similar to poison ivy in susceptible individuals. If hairs break off and blow around in the wind, they can cause difficulty breathing and headaches. While this insect can act as a defoliator in the larval stage, feeding on the leaves of many deciduous trees and shrubs, this activity may be secondary to concerns about public health risks. Care should be taken to avoid places infested with these caterpillars, exposed skin or clothing should be washed, and the appropriate PPE should be worn if working with these insects. Consult your physician if you have a reaction to the browntail moth.

• 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 here: https://ag.umass.edu/fact-sheets/emerald-ash-borer . Additional information about this insect is provided by the MA Department of Conservation and Recreation, here:https://arcg.is/j8TiD .

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. For an update about the progress of the biological control of emerald ash borer, visit Dr. Joseph Elkinton’s archived 2022 webinar now available here: https://ag.umass.edu/landscape/education-events/invasive-insect-webinars .

• 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) that are impossible to remove. The first adults appear in the end of May – June, but the numbers are low and infestations are rarely noticed at that time. It is easy to misidentify earthworms if only immatures found. By August and September, this is when most observations of fully mature jumping worms occur. At that time, snake worms become quite abundant, infestations become very noticeable, and may cause a lot of concern for property owners and managers.

For More Information:

UMass Extension Fact Sheets:

Earthworms in Massachusetts – History, Concerns, and Benefits: https://ag.umass.edu/landscape/fact-sheets/earthworms-in-massachusetts-history-concerns-benefits

Jumping/Crazy/Snake Worms – Amynthas spp.:

https://ag.umass.edu/landscape/fact-sheets/jumpingcrazysnake-worms-amynthas-spp

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

https://ag.umass.edu/news-events/highlights/jumping-worms-conference

 

Tree & Shrub Insect Pests, Continued:

• 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. They feed 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 Sawflies: There are a few species of sawflies that impact azaleas. Johnson and Lyon's Insects that Feed on Trees and Shrubs mentions three of them. Amauronematus azaleae was first reported in New Hampshire in 1895 and is likely found in most of New England. Adults of this species are black with some white markings and wasp-like. Generally green larvae feed mostly on mollis hybrid azaleas. Remember, sawfly caterpillars have at least enough abdominal prolegs to spell “sawfly” (so 6 or more prolegs). Adults are present in May, and females lay their eggs and then larvae hatch and feed through the end of June. There is one generation per year. Nematus lipovskyi has been reared from swamp azalea (Rhododendron viscosum). Adults of that species have been collected in April (in states to the south) and May (in New England) and larval feeding is predominantly in late April and May in Virginia and June in New England. One generation of this species occurs per year, and most mollis hybrid azaleas can be impacted. A third species, Arge clavicornis, is found as an adult in July and lays its eggs in leaf edges in rows. Larvae are present in August and September. Remember, Bacillus thuringiensis Kurstaki does not manage sawflies.

• Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs. Look for caterpillars with cone-like coverings of chewed up leaves, bark, and other plant parts. Common bagworm may be found on evergreen and deciduous host plants. More information can be found here: https://ag.umass.edu/landscape/fact-sheets/bagworm .

 

• 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 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. Tiny, early instar (black-headed) fall webworm caterpillars were observed feeding on birch in Hampshire County, MA on 7/5/2022. At this size, caterpillars skeletonize the leaves as they feed. 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.

• Hemlock Looper: As mentioned previously this season, two species of geometrid moths in the genus Lambdina are native insects capable of defoliating eastern hemlock, balsam fir, and white spruce. Adult moths lay their eggs on the trunk and limbs of hosts in September and October, and eggs will hatch by late May or early June. (L. fiscellaria caterpillars may be active between 448-707 GDD’s.) Monitor susceptible hosts for small, inch-worm-like caterpillars.

  The Massachusetts Department of Conservation and Recreation recently reported increased hemlock looper caterpillar activity in parts of Templeton, Warwick, and Northfield, MA as of 7/13/2022. (See photos.) At this time of year, any damage caused by these caterpillars on hemlock cannot be reversed and their activity is near its end for the season. Anyone with trees impacted in those areas should monitor remaining healthy hosts for potential activity in 2023.

  Where populations are low, no management is necessary. Hemlock loopers have several effective natural enemies.

• Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. The overwintering hemlock woolly adelgid generation (sistens) is present through mid-spring and produces the spring generation (progrediens) which will be present from early spring through mid-summer. HWA, unlike many other insects, does most of its feeding over the winter. Eggs may be found in wooly masses at the base of hemlock needles beginning in mid-March. Each wooly mass is created by a female who may then lay 50-300 eggs. Eggs hatch and crawlers may be found from mid-March through mid-July. Infested trees may be treated with foliar sprays in late April to early May, using Japanese quince as a phenological indicator. Systemic* applications may be made in the spring and fall, or when soil conditions are favorable for translocation to foliage. Nitrogen fertilizer applications may make hemlock woolly adelgid infestations worse.

  *UMass Extension has recently received questions about systemic active ingredient options that may be used to manage hemlock woolly adelgid as an alternative to neonicotinoid insecticides. A couple of options include but are not limited to: abamectin (avermectin/milbemycin), acephate (organophosphate), and azadirachtin (unknown/uncertain mode of action). General use products are available, and each of these active ingredients are labeled for use on trees and/or shrubs. Many products are labeled for use against hemlock woolly adelgid or adelgids.

  Of these active ingredients, azadirachtin is considered to be reduced risk. It is generally considered a safe option for honeybees and other beneficial insects, however some products state that azadirachtin is toxic to fish and other aquatic invertebrates (and as such, the products come with special instructions for precautions when using them near water).

  Unlike the neonicotinoids (dinotefuran and imidacloprid, primarily), these systemic active ingredient alternatives do not have efficacy data for the management of hemlock woolly adelgid readily available in the scientific literature. Further research concerning abamectin, acephate, and azadiractin (as well as chlorantraniliprole, a ryanodine receptor modulator/diamide/anthranilic diamide) and their efficacy against hemlock woolly adelgid is needed (McCarty and Addesso, 2019).

• Hibiscus Sawfly: The larvae of the hibiscus (mallow) sawfly, likely Atomacera decepta, may be observed feeding on hibiscus hosts at this time. Sawfly larvae develop into wasp-like adults (Order: Hymenoptera) and therefore these “caterpillars” will not be managed by Bacillus thuringiensis var. kurstaki which is specific to the Lepidoptera (caterpillars that develop into moths or butterflies as adults). Reduced risk active ingredients such as spinosad are labeled for use against sawfly larvae. However, given that hibiscus are very attractive to pollinators, non-chemical management options such as hand picking and disposing of larvae, when possible, are best. Spinosad is toxic to pollinators until it dries. For more information about the risks of insecticide active ingredients to pollinators, visit: https://ag.umass.edu/landscape/fact-sheets/tree-shrub-insecticide-active-ingredients-risks-to-pollinators-other-non .

The hibiscus (mallow) sawfly adult female uses her ovipositor to cut slits into leaf surfaces to deposit her eggs. Larvae emerge from these eggs and begin by first feeding on leaf undersides when small, and then move to feed on leaf surfaces as they grow in size. Only large leaf veins may be left behind if the population is large enough. Larvae have been observed moving to the base of the plant to pupate. Adults emerge and in some locations in the US, multiple generations have been recorded per year. This insect is known in the mid-Atlantic and Midwest states, but was reported feeding on Hibiscus spp. in Connecticut in 2004 and 2005 and has previously been reported in Massachusetts. The timing of the life cycle of this insect, as well as how many generations occur per year in Massachusetts, however, is not fully understood. Some research has shown that Hibiscus acetosella, H. aculeatus, and H. grandiflora seem to either exhibit some resistance to or tolerance of hibiscus sawfly feeding. In one study, all three had few if any eggs or larvae and were given the lowest damage rating among the species evaluated. This insect also does not feed on rose of Sharon or H. rosa-sinensis. It has, however, been reported to “voraciously” feed on H. moscheutos, H. palustris, H. militaris, and H. lasiocarpus.

• ​​​​​​​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. Most plants can tolerate multiple years of feeding from this insect, and foliage will appear brown. Repeated yearly feeding can occasionally 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: https://ag.umass.edu/landscape/education-events/insectxaminer
• Japanese Beetles: Popillia japonica adult beetles are active. Adult female beetles will lay their eggs primarily by early August, however eggs may be laid into September. Females lay these eggs in groups in soil cavities they excavate 2-4 inches down. Japanese beetles overwinter as nearly grown grubs in the soil which are capable of evading freezing behaviorally by moving below the frost line. As soils warm in the spring, larvae become active and feed on the roots of grasses. Pupation occurs 1-3 feet below the soil surface. Adults emerge from these lawn areas and disperse to feed on foliage, mate, and return to turf-type locations for females to lay their eggs. Japanese beetle adults use aggregation pheromones (chemicals that signal between individuals) to call in others of the same species. These pheromones and volatile chemicals from host plants being fed upon are thought to be the reason why large numbers of these beetles can be found feeding together. Adult beetles feed on foliage and flowers, often skeletonizing leaves until they appear lace-like. Larvae are highly damaging turf pests. Tree and shrub hosts are comprised of more than 300 species including but not limited to rose, mountain-ash, willow, linden, elm, Japanese and Norway maples, birch, sycamore, rose of Sharon, ornamental apple, and many others. Adult beetles are often attracted to feeding on sunny areas of the plant. Many organisms are parasitoids of Japanese beetles, such as two wasps that attack overwintered grubs in the spring, and a tachinid fly (winsome fly: Istocheta aldrichi) which parasitizes newly emerged adult beetles. Other organisms act as generalist predators with Japanese beetles on their menus, including but not limited to ants, certain other beetles, small mammals, and birds.
• Lacebugs: Stephanitis spp. lacebugs such as S. pyriodes can cause severe injury to azalea foliage. S. rhododendri can be common on rhododendron and mountain laurel. S. takeyai has been found developing on Japanese andromeda, leucothoe, styrax, and willow. Stephanitis spp. lace bug activity should be monitored through September. Before populations become too large, treat with a summer rate horticultural oil spray as needed. Be sure to target the undersides of the foliage in order to get proper coverage of the insects. Certain azalea and andromeda cultivars may be less preferred by lace bugs.

• Lilac Borer: Podosesia syringae is a clearwing moth pest of lilac, privet, fringetree, and ash. (It is also known as the ash borer, not to be confused with the emerald ash borer.) Adults mimic paper wasps. Larvae are wood-boring, and signs and symptoms include branch dieback, holes, and occasionally, sawdust-like frass accumulated on bark. Larvae bore into stems, trunks, and branches, chewing an irregularly shaped entrance hole. Peak adult moth flights may occur in the northern portion of this insect’s range in June and are usually over by August 1st. Pheromone traps can be used to time adult emergence. Adult females lay flattened, oval, and tan eggs that are deposited singly or in clusters on bark crevices, ridges, and sometimes smooth bark; but usually laid in or near wounds in the bark. On average, 395 eggs are laid by each female. After hatch, larvae chew into the bark and feed laterally and then vertically in phloem tissue. Larvae overwinter in tunnels in the final instar and resume feeding in the spring. Adults emerge through a round exit hole (4-5 mm. in diameter). This insect may be targeted between 200-299 GDD’s, base 50°F.

• Magnolia Scale: Neolecanium cornuparvum is distributed throughout the eastern United States. Host plants include: Magnolia stellata (star Magnolia), M. acuminata (cucumber Magnolia), M. liliiflora ‘Nigra’ (lily Magnolia; formerly M. quinquepeta), and M. soulangeana (Chinese Magnolia). Other species may be hosts for this scale, but are 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.

• Taxus Mealybug: Dysmicoccus wistariae will produce honeydew and lead to sooty mold growth, yellowing of needles, and sparsely foliated plants. Eventual dieback may be possible. This species is commonly associated with taxus in New England, but can be occasionally found on dogwood, rhododendron, Prunus spp., maple, andromeda, and crabapple. These mealybugs are found on stems and branches and particularly like to congregate at branch crotches. Taxus mealybug feeds in the inner bark tissue of the trunk and branches. Adult females are present from June to August and give birth to living young in the summer. Immatures overwinter. A single generation may occur per year in New England, but areas to the south can have multiple generations of this insect. Management may be targeted between 246-618 GDD’s, base 50°F. Horticultural oil and neem oil may be used.

• Tuliptree Aphid: Illinoia liriodendri is a species of aphid associated with the tuliptree, wherever it is grown. Depending upon local temperatures, these aphids may be present from mid-June through early fall. Large populations can develop by late summer. Some leaves, especially those in the outer canopy, may turn brown or yellow and drop from infested trees prematurely. The most significant impact these aphids can have is typically the resulting honeydew, or sugary excrement, which may be present in excessive amounts and coat leaves and branches, leading to sooty mold growth. This honeydew may also make a mess of anything beneath the tree. Wingless adults are approximately 1/8 inch in length, oval, and can range in color from pale green to yellow. There are several generations per year. This is a native insect. Management is typically not necessary, as this insect does not significantly impact the overall health of its host. Tuliptree aphids also have plenty of natural enemies, such as ladybeetles and parasites.
• 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. 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. Adult beetles emerge following pupation in early July. At this time, adult beetles will resume feeding, mate, and the females will lay their eggs in pits they chew at the ends of twigs. Eggs overwinter. Adults may also migrate to previously not yet infested plants. Adult viburnum leaf beetle feeding appears different from that of the larvae. Adults chew oblong holes in leaves. 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/ .

• White Satin Moth: Leucoma salicis has again been reported from Beartown State Forest (Berkshire County) on 6/8/2022 by the Massachusetts Department of Conservation and Recreation, Forest Health Program (photos courtesy of Eric Reynolds). This is the same location that caterpillars of this species were seen defoliating their hosts in 2020 and 2021.

The caterpillars of this species have a unique color pattern, which helps us distinguish them from others. The dorsal (back) side of the caterpillar is marked with 10-11 white, intersegmental spots as well as paired, red “setal warts”. The sides of the caterpillars are blueish gray. These caterpillars are known to the edges of waterways, woodlands, and forests from Canada to northwestern Connecticut and central New York. One generation occurs per year with mature caterpillars known in May and June. Host plants include aspen, poplar, and willow, the leaves of which are fed upon by the caterpillars of this species.

The white satin moth was introduced from Europe and first reported between Boston, MA and Hampton, New Hampshire in 1920. This insect is said to overwinter in the third instar (caterpillars pass through seven instars), either individually or in small groups. In the springtime, caterpillars leave their areas of hibernation to feed on nearby leaves. Caterpillars spin a thin cocoon between leaves or between exfoliating or thick bark crevices. Pupae are dark brown/black and often in a thin, loose silken sack. Pupae also sport brightly colored, yellow setae (hairs) that make them quite attractive. Pupation begins by the end of June. Shortly thereafter, moths emerge and females lay egg masses covered in a frothy, white material from July – mid-August. Eggs hatch sometime in August, and larvae will conduct feeding in August and September.

While caterpillars of this species are not noted to be of particular concern with regard to causing allergic reactions such as dermatitis, they are a type of tussock moth and do possess hairs, so they should not be handled and should be approached with caution particularly by sensitive individuals.

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: http://massnrc.org/pests/pestreports.htm .

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

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