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Landscape Message: August 19, 2022

August 19, 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 September. The next message will be posted on September 9. 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:

Scouting Information by Region

Environmental Data

The following data was collected on or about August 17, 2022. Total accumulated growing degree days (GDD) represent the heating units above a 50º F baseline temperature collected via regional NEWA stations ( 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


Soil Temp
(°F at 4" depth)

(2-Week Gain)

Time/Date of Readings

2-Week Gain

2022 Total









12:00 PM 8/17







3:00 PM 8/17







10:00 AM 8/17







5:00 PM 8/17







5:45 AM 8/17







7:45 AM 8/17







1:00 PM 8/17







6:30 PM 8/17








* = information not available

Almost all of MA is in either a (D2) severe drought or (D3) extreme drought as of 8/16:   Massachusetts | U.S. Drought Monitor (  Town watering restrictions:               


Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)

Clematis paniculata (sweet autumn clematis)









Polygonum cuspidatum (Japanese knotweed)









Clethra alnifolia (summersweet clethra)









Hibiscus syriacus (rose-of-Sharon)









Buddleia davidii (butterfly bush)









Campsis radicans (trumpet vine)









Hydrangea paniculata (panicle hydrangea)









* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature for the period from August 3 through August 17 was 73℉ with a high of 90℉ on August 5 and a low of 53℉ on August 14. August 3-9 was hot with highs in the upper 80s and lows in the 70s. August 10 thru 17 included daytime highs in the 70s and lows primarily in the 60s. Overall, the period had more sunny/mostly sunny days than cloudy days. Precipitation occurred on August 9, 11 & 17 totaling approximately one third of an inch. The combination of precipitation on the 9th and the cooler temperatures that followed provided a slight break from the intense hot, dry, sunny conditions that preceded it. Soils are currently dry and drought conditions are severe to extreme resulting in many water districts implementing mandatory water restrictions. Some herbaceous plants seen in bloom include purple coneflower (Echinacea purpurea), black eyed susan (Rudbeckia hirta), balloon flower (Platycodon grandiflorus), garden phlox (Phlox paniculata), hardy hibiscus (Hibiscus moscheutos), boneset (Eupatorium perfoliatum), Russian sage (Salvia yangii), and some goldenrods (Solidago spp). Some woody plants seen in bloom include hydrangeas (Hydrangea spp.), mimosa (Albizia julibrissin) and seven son tree (Heptacodium miconioides).

Pests/Problems: Drought conditions are impacting plant health. Most unirrigated lawns are crispy as are some irrigated lawns. The extent of the drought will result in permanent damage to lawns. The likelihood of recovery from summer dormancy continues to decrease as drought conditions continue. Hopefully moisture will arrive in the coming weeks to allow for fall repairs. Ornamental plants are also suffering; wilting, scorch, stress, premature leaf drop and death can be seen in unirrigated landscapes. Unestablished plants with inadequate supplemental watering are failing. Now is an important time to water woody plants to avoid lasting damage. Insect damage seen during the period includes pine tip moth damage to pitch pine and turpentine beetle damage to pitch pine. Turpentine beetle is very active for this time of year and, combined with stress from pine tip moth and drought, are likely to lead to widespread attacks. Additional insecticide treatments may be needed to protect high value pitch pines. Flagging as the result of black oak gall wasp damage has been seen in several areas of the mid-Cape. Other insects or insect damage seen during the period include hibiscus sawfly on hardy hibiscus, rose slug sawfly damage on rose (no larvae present), lacebug damage on andromeda and azalea, boxwood leafminer damage on boxwood, two spotted spidermite damage on numerous herbaceous plants, hemlock elongate scale on hemlock, white pine aphid on Japanese white pine, daylily leafminer damage on daylily, chilli thrips damage on hydrangea, and eriophyid mites on linden and other woody species. Disease symptoms and signs seen during the period include pear trellis rust which is widespread and causing defoliation, volutella blight on boxwood, black spot on rose, cedar apple rust on crabapple, cercospora leaf spot on hydrangea and powdery mildew on just about any plant. Weeds seen in bloom include spotted knapweed (Centaurea stoebe), pokeweed (Phytolacca americana), lambsquarters (Chenopodium album), purslane (Portulaca oleracea), horseweed (Conyza canadensis), carpetweed (Mollugo verticillata), crabgrass (Digitaria spp.), perennial sow thistle (Sonchus arvensis) and spotted spurge (Euphorbia maculata). Keep a keen eye out for yellow jacket and bald-faced hornet nests while working in unfamiliar landscapes.

Southeast Region (Dighton)

General Conditions: Despite scattered showers and a singular downpour, we are still experiencing extreme drought over the south coast. Our rain deficit for the year is currently approximately 9.5 inches, about a quarter of the average yearly precipitation. Watering bans remain in effect throughout the area. Thankfully day high temperatures have abated from the brutal nineties of previous weeks to more temperate seventies and low eighties. Nights have ranged from the mid-sixties to as low as the upper fifties. Very light showers and morning dew have been the primary source of moisture except for the localized downpour on Thursday the eleventh which contributed to most of our rainfall. That was enough to restore some turgor to plants although the devastation and threat to local wildlife is apparent throughout the region. Plants in flower include: Albizia julibrissin (mimosa, silk tree), Daucus carota (Queen Anne's lace), Franklinia alatamaha (Ben Franklin tree), Clethra alnifolia (coastal sweetpepperbush), Eutrochium maculatum (spotted Joe-Pye weed), Helianthus tuberosus (Jerusalem artichoke), Hosta plantaginea (plantain lily), sedum 'Autumn Joy' (Hylotelephium hybrid), Lagerstroemia sp. (crepe myrtle), Miscanthus sinensis (Chinese silver grass), Oenothera biennis (evening primrose), Oxydendrum arboreum (sourwood), Rhus corallum (shining sumac), Rosa 'Knockout' (rose), Rudbeckia spp, Salvia yangii (Russian sage), Solidago juncea (early goldenrod), and Styphnolobium japonicum (Japanese pagoda tree, Sophora japonica).

Pests/Problems: Severe and extreme drought conditions are threatening the survival of many individuals among the flora and fauna of the region. Shallow ponds and low swamp lands are dry. Plants on shallow soils and south-facing slopes are everywhere wilted, brown, and dead. Few pollinators can be observed, among them blue mud daubers, bumble bees and monarch butterflies. Small songbirds have flocked up. Hummingbirds are still about but seem to be frantically revisiting the few remaining nectar sources. Almost all of MA is in either a (D2) severe drought or (D3) extreme drought as of 8/16Massachusetts | U.S. Drought Monitor ( . Town watering restrictions: .

North Shore (Beverly)

General Conditions: Very hot and humid conditions persisted during the first half of this two week reporting period with day temperatures ranging from mid 90s to high 90s.Temperatures above 90℉ were recorded for six consecutive days. Night temperatures during these days were in the mid 70s. Halfway through the reporting period a cold front came through and brought cooler temperatures and lower humidity. Day temperatures during the last half of the reporting period were in the mid 70s to low 80s and night temperatures were in the mid 60s to low 70s. The average daily temperature was 75℉ with the maximum temperature of 98℉ recorded on August 7 and 8, and the minimum temperature of 55℉ recorded on August 14, 15 and 16. There was no rain recorded at Long Hill during the last two weeks. We need rain!! Woody plants seen in bloom include: silk tree or mimosa (Albizia julibrissin), panicle hydrangea (Hydrangea paniculata), butterfly bush (Buddleia davidii), rose-of-Sharon (Hibiscus syriacus), chaste tree (Vitex agnus-castus), daphne (Daphne spp.) and summersweet clethra (Clethra alnifolia). Herbaceous plants seen in bloom include: garden phlox (Phlox paniculata), hostas (Hosta spp.), sedums (Sedum spp.), black eyed Susan (Rudbeckia hirta), coneflower (Echinacea purpurea), cranesbill (Geranium spp.), milkweed (Asclepias spp.), water lily (Nymphaea odorata) and summer annual plants.

Pests/Problems: It has been very dry and non irrigated turf has turned brown due to drought stress. A lot of other plants are also showing signs of drought stress. According to the US Drought Monitor, the area is in extreme drought. Powdery mildew was observed on some lilac and magnolia scales were observed on magnolia. Crabgrass, yellow nutsedge and other drought resistant weeds are thriving. Ticks and mosquito activity has slowed down but it is still important to protect yourself with a repellent when working outdoors during the time of dusk or dawn.

East Region (Boston)

General Conditions: This two week reporting period began hot and dry. We had six consecutive days above 90 degrees, from August 4th through August 9th. We received 0.69 inches of irrelevant precipitation over those six days. Temperatures cooled from the 10th through the 17th, averaging 78℉. Overnight temperatures averaged 62℉ with one overnight low of 55℉ on August 14th. Despite the cooler temperatures and several threats of significant precipitation, we gained only one additional tenth of an inch, for a total of 0.72 inches the entire month of August. Some Hydrangea Aphids sucking juices out of butterfly weed on 8/18/22 (K. Ganshaw) Beneficial lady beetle eating aphids on butterfly weed on  8/18/22 (K. Ganshaw) paniculata are looking nice in the landscape. Styphnolobium japonicum (Japanese scholar tree) is in full bloom, often seen throughout out Brookline in large traffic islands. Beneficial insects abound in the garden; lady bugs are actively feeding on aphids.

Pests/Problems: Lack of soil moisture is the main concern. Early leaf drop is significant throughout the landscape. Yellow nutsedge (Cyperus esculentus) and crabgrass (Digitaria spp.) account for the majority of the green component in otherwise dormant lawns.

Metro West (Acton)

General Conditions: The summer season is winding down. The length of daylight is shortening daily by the minute and overnight temperatures are cooling off. On the 16th, the daytime length was at 13:52 with sunrise at 5:52 a.m. and sunset at 7:44 p.m. To put that into perspective, the previous day’s length of daylight was measured at 13:55. We experienced our second heat wave of the summer during this reporting period and it lasted 6 days from the 4th to the 9th with temperatures recorded each day in the mid to high 90’s, averaging 96.83°F. The hottest day was the 4th with a high of 98.6°F recorded. The historical monthly average rainfall for August is 3.72”. During this past two-week reporting period 0.8” of rain was recorded bringing the monthly total to 0.82”. Observed in some stage of bloom this past week were the following woody plants: Buddleia spp. (butterfly bush), Campsis radicans (trumpet vine), Clethra alnifolia (summersweet), Hibiscus syriacus (rose-of-Sharon), Hydrangea arborescens (smooth hydrangea), H. paniculata (panicle hydrangea), and Potentilla fruiticosa (potentilla). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Boltonia asteroides (Bolton’s aster), Daucus carota (Queen Anne's lace), Echinacea purpurea (coneflower) and its many cultivars, Hemerocallis spp. (daylily), Kirengeshoma palmata (yellow wax bells), Lythrum salicaria (loosestrife), Patrinia gibbosa (patrinia), Perovskia atriplicifolia (Russian sage), Phlox carolina (Carolina phlox), P. paniculata (garden phlox), Platycodon grandiflorus (balloon flower), Rudbeckia fulgida var. sullivantii 'Goldsturm' (black eyed Susan), and Solidago spp. (goldenrod).

Pests/Problems: The continued lack of any substantial and steady rain continues to be a real concern for our trees and shrubs in the landscape especially compounded with the recent heat wave and hot, windy, and humid weather. The Massachusetts Office of Energy and Environmental Affairs declared that 100% of the State was experiencing drought conditions. A Level D3 – Extreme Drought - has been declared for much of this area, as conditions worsen. Impacts of the drought are many and some include outdoor water restrictions, brittle trees, trees susceptible to pests, and wildfire risks. Signs of plant stress are apparent in the landscape including premature leaf drop and flagging.

Central Region (Boylston)

General Conditions: Once again the reporting period started with the maximum temperatures above 90°F with the average maximum temperature being 88°F. The second reporting week (8/10/22-8/16/22) gave us a break from the 90’s and brought much needed cooler daytime and nighttime temperatures, with the lowest temperature being just shy of 53°F. We continue to receive very little rainfall with the total amount being 0.21. In Boylston, the drought is obvious, even the plants we are irrigating every other day are showing signs of stress. We are seeing the early signs of fall; the Solidago juncea (early goldenrod) and Euthamia graminifolia (grass-leaved goldenrod) are flowering. The Liatris spicata (dense blazing star) is close to being completely done flowering. The drought is certainly taking a toll on the length that perennials are flowering.

Pests/Problems: The powdery mildew continues to spread throughout the garden, we are now seeing it on witch hazels, dogwoods and white turtlehead. As of August 16th, the Central Region is now in a D3/"Extreme Drought". There seems to be no sign of moisture in the forecast in the next 10 days, but we continue to hope for a wet fall. The poison ivy is thriving throughout the drought. Our most common garden weeds, ragweed, large crabgrass, and smartweed are large and flowering. The Japanese beetles are still being sighted on the summersweet and rose of Sharon.

Pioneer Valley Region (Amherst)

General Conditions: Late summer continues in the Pioneer Valley as the daylight fades and we round the corner into the last third of August. This can be a peaceful time of the year in the tri-counties, just prior to the beginning of a new fall semester when the students return. After two brutal heat waves in late July (7/25–7/28) and early August (8/4–8/9), conditions have moderated with the return of low humidity and cool nights. However, the drought has stubbornly persisted and full sun landscapes are appearing torn and frayed after weeks of limited rainfall. According to the National Centers for Environmental Information, a division of NOAA, average precipitation across Massachusetts from May through July (3-month) totaled only 7.09”, which is the 8th driest on record and lowest since 2016. In addition, the NRCC shows that precipitation through the first half of August was paltry throughout most of New England and New York, compounding our current rainfall deficit. The 2016 summer drought was one of the worst on record, but if the rest of August and September continue on the current trajectory, the 2022 season may be comparable. If your watering efforts feel futile, remember that supplemental irrigation is meant to be just that; supplemental to natural rainfall. Deep watering on longer intervals is preferable for many plants, as it helps to develop a deeper rooting system that is more resistant to drought stress. Watering for only a short duration can promote an overabundance of roots near the surface. Even worse, it may only serve to wet the mulch layer, which can absorb significant amounts of moisture once fully dried. More stringent water use restrictions are making it difficult to irrigate, so stay aware of changing municipal water use guidelines. Many landscape conifers, like arborvitae, juniper and false-cypress can flush new growth at this time, so fertilization can help to stimulate this new growth (provided the trees are not drought-stressed). There’s still an abundance of late season color with various perennials and annuals in bloom, such as cleome, black-eyed susan, dahlia, zinnia, cardinal flower, lobelia, hibiscus and late hostas. The nighttime sounds of crickets, katydids and cicadas continue.

Pests/Problems: Drought stress is one of the most important predisposing stresses for trees and shrubs, making them susceptible to a range of disease and insect problems. Across the UMass campus, a variety of mature trees are exhibiting leaf scorch, wilt, or shedding older browning leaves, such as: London planetree, katsura, stewartia, serviceberry, apple, birch, yellowwood, silver maple and Japanese maple. Many landscape oaks are weathering the dry conditions well, owing to their tolerance of moderate drought conditions. Spider mites thrive during extended dry periods and the damage they cause is often only visible long after their populations have started to crash. Actively scout for these pests to avoid injury. Lacebug damage can be exacerbated by drought stress, so ensure andromeda, azalea and rhododendron are free of these insects. Continue to scout for annual and perennial fruiting bodies produced by wood-rotting pathogens of trees. These mushrooms/conks may be the only indication that a tree is infected and may develop on lateral roots around the tree or directly at the base of the trunk. Dry weather suppresses the activity of many fungal pathogens, so some late season diseases seem to be less abundant. In particular, Tubakia leaf blotch of oak and Septoria leaf spot of birch and dogwood.

Berkshire Region (Great Barrington)

General Conditions: The past 2 weeks could best be characterized as hot and humid, with the exception of some recent days. The period from August 4-8 was particularly hot as temperatures reached into the 90s at the three County weather reporting stations, i.e. North Adams, Pittsfield, and Richmond. North Adams recorded 93℉ on the 4th, 92℉ on the 6th, and 91℉ on the 8th. Pittsfield high temperatures were 92℉ on the 4th, 90℉ on the 6th and 8th. Richmond hit 93℉ on the 4th and 91℉ on both the 6th and 8th. After that heat wave, there was a bit of a cool down beginning on August 9th as day time temperatures were mostly in the 70s. There were also a few nights when the thermometer dipped into the upper 40s: North Adams and Pittsfield recorded lows of 49℉ the 14th and 49℉ on the 16th. Besides the heat, the biggest concern has been the lack of significant rainfall. Over the two week scouting period rainfall amounts were 1.22 inches in North Adams, 0.40 inches in Pittsfield, 0.22 inches in Richmond, and 0.71 inches in West Stockbridge. Based on data from the Pittsfield site, precipitation for the year through August 16 is 3.80 inches below normal. According to the U.S. Drought Monitor, parts of Berkshire County are categorized as being in either “Moderate Drought” or "Severe Drought”. Needless to say, it has been dry and parts of the landscape are showing the effects. Younger woody plants which were defoliated by spongy moth earlier this year have recovered to some extent with regrowth of leaves. Large trees do not show much re-foliation. The showers of late afternoon and evening on the 17th should provide a little relief.

Pests/Problems: Pest activity since the scourge of spongy moth caterpillars has been relatively minor. Japanese beetles were common earlier this summer but the numbers are very low at this time. The most common plant pests observed now are spider mites and aphids. Nuisance insects are mosquitoes, gnats, and black-legged ticks. Plant diseases observed included powdery mildew on a wide range of plant materials, leaf spot diseases on maples and black spot on roses. A leaf and stem blight was found on some peonies at one scouting site. The blight appears as purple lesions on the stems. The effects of drought are apparent as large patches of browned turfgrass and the browning and wilting of foliage on some woody and herbaceous plants. Ferns seemed especially affected by dry conditions.

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


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

  • Dutch elm disease, caused by Ophiostoma novo-ulmi, on Valley Forge American elm (Ulmus americana ‘Valley Forge’). The tree is <20-years-old and has been established at the site for ~15 years. It resides in full sun with well-drained soils surrounded by lawn. Earlier this summer, leaf yellowing and wilting became visible in the canopy and vascular staining was abundant on small stems and branches. Black spot anthracnose was also present on the submitted foliage. Valley Forge has been repeatedly shown through manipulated studies to be the most disease-resistant cultivar of American elm. But unfortunately, some trees are overtaken by the disease and die.
  • Shoot tip dieback and needle blight of dawn redwood (Metasequoia glyptostroboides) caused by Pestalotiopsis. This summer, canopy dieback developed from the main leader and spread throughout many of the lateral branches. The tree is young, less than 10-years-old, and was transplanted three years ago. The site is described as a dry, open area with full sun and sandy soils. Supplemental water is provided on a regular basis and the volume appears sufficient given the lack of regular rainfall this season. Dawn redwoods are tolerant of dry sites once they become established but prefer moist soils. Pestalotiopsis is widespread on arborvitae and juniper but has a broad host range among conifers. The submitted shoots had brown and wilted needles that were thoroughly colonized by the pathogen. The fungus often requires a predisposing stress and it’s possible the open setting and recent time since planting were factors. Despite the supplemental water, drought stress may also be to blame.
  • Reddening of flowering dogwood (Cornus florida) foliage caused by dogwood powdery mildew (Erisyphe pulcra). Powdery mildew, caused by Erysiphe pulchra, on flowering dogwood (Cornus florida). Two trees that are believed to be >70-years-old and are situated next to a brick terrace in full sun. In late May of this year, the foliage appeared curled and distorted with an unhealthy reddish color. Some premature shedding was observed but this was not a major concern. Dogwood PM can result in leaves that curl downward, giving the appearance that the tree is wilting from a vascular disease. The disease has occurred throughout the region for many years, but disease severity seems to be increasing. The distinct reddish discoloration of the foliage is often a good diagnostic symptom but the diffuse, white-colored webbing of fungal mycelia can often be readily observed too .
  • Glyphosate injury on privet (Ligustrum sp.). The plants are eight to ten-years-old, experience a mixture of sun and shade in mulched planting beds, and receive supplemental water from overhead sprinklers. Over the past several years, undersized, distorted and tufted masses of leaves have emerged each spring. Similar symptoms have appeared on nearby dogwood, weigela and rose. Spray drift has been affecting all of the plants, but the exposure continued to be non-lethal. Even minor amounts of glyphosate drift can cause injury and privets are particularly susceptible to the chemical. Non-target injury can often be avoided by applying a thick stream of glyphosate close to the ground. When applied as a fine mist, droplets are easily spread even from minor air currents.
  • Verticillium wilt of bottlebrush buckeye (Aesculus parviflora) caused by Verticillium dahliae. The tree is likely 10- to 15-years-old and was transplanted to the site seven-years-ago. The tree receives a mix of sun and shade in dry, well-drained soils, but drip irrigation does provide supplemental water. In 2019, leaves began yellowing from the top of the canopy in mid-summer, followed by premature shedding and branch dieback. Since that time, the tree has died back to the ground each year and new growth develops from suckers the following year. The submitted stems exhibited green-colored vascular staining that is typical of Verticillium wilt.

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


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:

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:

Direct Supervision Frequently Asked Questions:

Wandering Caterpillars:

  • Datana Species Caterpillars: There are four species of insects in the genus Datana which have similar looking caterpillars. One such caterpillar was recently seen wandering a road in Hampshire County, MA on 8/16/2022. The caterpillars of Drexel’s datana (Datana drexelii) may be found from Nova Scotia to Kentucky and South Carolina. In the northern portion of this insect’s range, one generation occurs per year. D. drexelii may be distinguished from the others by an “orange rump patch” which is formed by the convergence of some of its stripes (Wagner, 2005). Blueberry, other heaths, and witch hazel are reported as hosts. D. ministra or the yellow-necked caterpillar, may be found on similar hosts, but tends to be primarily black in color with yellow stripes down the sides. Angus’s Datana (D. angusii) has reddish prolegs, a black thoracic shield, and may be hairier. For that species, butternut, hickory, and walnut are listed as preferred. The spotted Datana (D. perspicua) may have broader yellow stripes and the base of each proleg is somewhat reddened, favoring sumac, smoketree, and possibly oak. Datana spp. caterpillars have been reported as in decline, perhaps due to the impact of Compsilura concinnata, a tachinid fly parasitoid released very early on (1906) in the fight against spongy moth (Lymantria dispar). Unfortunately, that tachinid fly species is a generalist and not specific to the spongy moth. Therefore, if you find a cluster of these caterpillars munching away and they can be tolerated in their given location, leave them be. Right now, the caterpillars appear to be large and wandering from their former feeding locations. This is the time of year where certain species of Datana caterpillars seek out appropriate locations to burrow into the soil in order to pupate and overwinter.

  • Woolly Bear Caterpillars/Isabella Tiger Moth Caterpillars: Pyrrharctia isabella is native from Canada to Florida and Texas. In the eastern US, there are 2 generations per year. On 8/16/2022, wandering woolly bear caterpillars were seen on a road in Hampshire County, MA. The host plants of this caterpillar include many low-growing, herbaceous and woody plants such as dandelion, grass, lettuce, meadowsweet, and nettle. Nearly grown caterpillars will overwinter under the leaf litter or other protected areas, resuming feeding in the spring. They are frequently seen wandering paved roads and driveways and are most conspicuous around the time of the first frosts. The reason for this extensive wandering is unknown, and such wandering in roadways puts them in danger. Pupation occurs in the spring and adults may be present from April through September. “Rural legend” states that the width of the orange band can be used as a predictor of winter severity. Narrow brown bands supposedly indicate a cold, harsh winter whereas wide brown bands indicate a mild winter. This has been debunked – the amount of brown on the caterpillar is widely variable. With each molt of these caterpillars, the black hairs are replaced with more brown – so older instar caterpillars will have the broadest brown band.

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: Since then, additional mosquito samples have tested positive for the virus (WNV). As of 8/18/2022, no eastern equine encephalitis (EEE) positive mosquito samples, human cases, or animal cases have been detected or reported by DPH.

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:  

For more information about mosquitoes in Massachusetts, visit:

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: and .

  • 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). 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: .

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:

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

  • 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. If you are concerned that you have found or photographed a northern giant hornet, please report it here: . 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 northern giant hornet and is found here: . 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.

    *For more information about the recent common name change for Vespa mandarinia, please visit:

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

Invasive Insects & Other Organisms Update:

  • Spotted lanternfly egg masses. (Photo: Tawny Simisky)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.

In the beginning of August 2022, the MA Department of Agricultural Resources (MDAR) announced an additional detection of an established population of the spotted lanternfly in Springfield, MA. MDAR is urging the public to be on the lookout for this pest, especially if they live or work in the Springfield area, and to report it immediately. For more information about the detection in Springfield, visit: .

Currently, the only established populations of spotted lanternfly in Massachusetts are in a small area in both Fitchburg and Shrewsbury, MA (Worcester County) and the latest detection of a population of this insect in Springfield, MA (Hampden County; officials are currently working on determining the size of the population in Springfield). 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, and Springfield 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:

Fact Sheet:

*NEW*: Center for Agriculture, Food, and the Environment:

From the MA Department of Agricultural Resources:

Fact Sheet and Map of Locations in MA:

  • Trees and hillsides defoliated by spongy moth (Lymantria dispar) in Mount Washington (Berkshire County), MA on 7/5/2022. (Image Courtesy of: Sarah Grubin, MA Department of Agricultural Resources)Hillsides defoliated by spongy moth (Lymantria dispar) in Mount Washington (Berkshire County), MA on 7/5/2022. (Image Courtesy of: Sarah Grubin, MA Department of Agricultural Resources)Trees defoliated by spongy moth (Lymantria dispar) in Mount Washington (Berkshire County), MA on 7/5/2022. (Image Courtesy of: Sarah Grubin, MA Department of Agricultural Resources)Spongy Moth: Lymantria dispar activity in parts of Berkshire County was heightened this year. Many areas have experienced defoliation and large numbers of caterpillars. The good news is, spongy moth caterpillar activity for 2022 is at 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 were Spongy moth caterpillars killed by the NPV virus and the fungus, Entomophaga maimaiga, viewed in Williamstown, MA (Berkshire County) on 6/21/2022. (Image Courtesy of: Steve L.)Spongy moth caterpillar killed by the NPV virus, viewed in Sheffield, MA (Berkshire County) on 6/16/2022. (Image Courtesy of: Tom Ingersoll) The largest decline in spongy moth caterpillar numbers has been due to infection by either the fungus Entomophaga maimaiga or by the NPV virus. 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.   

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. There are no chemical management strategies applicable for spongy moth at this time in its life cycle. Scout for overwintering egg masses this fall and winter to plan if management might be applicable in Berkshire County next spring.

Why did the common name for Lymantria dispar change recently? More information is available here:

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


  • 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: or .

  • 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: . 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 a great update on the current status of browntail moth in Maine, including excellent photos of newly hatched browntail moth caterpillars compared to a common lookalike (fall webworm), visit: .

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.

  • Adult emerald ash borer. (Photo: Tawny Simisky) 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: . Additional information about this insect is provided by the MA Department of Conservation and Recreation, here: .

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.

  • 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:

*NEW* Resource with Over 70 Questions and their Answers: Invasive Jumping Worm Frequently Asked Questions:

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:


Tree & Shrub Insect Pests, Continued:

  • 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.
  • Bagworm bag. (Photo: Tawny Simisky) 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: .

These caterpillars develop into moths as adults. Their behaviors, life history, and appearance are interesting. The larvae (caterpillars) form “bags” or cases over themselves as they feed using assorted bits of plant foliage and debris tied together with silk. As the caterpillars feed and grow in size, so does their “bag”. Young, early instar caterpillars may feed with their bag oriented skyward, skeletonizing host plant leaves. As these caterpillars grow in size, they may dangle downward from their host plant, and if feeding on a deciduous host, they can consume the leaves down to the leaf veins. Pupation can occur in southern New England in late September or into October and this occurs within the “bag”. Typically, this means that the caterpillars could encounter a killing frost and die before mating could occur. However, in warmer areas of Massachusetts or if we experience a prolonged, warm autumn, it is possible for this insect to overwinter and again become a problem the following season. If the larvae survive to pupation, adult male moths emerge and are winged, able to fly to their flightless female mates. The adult male is blackish in color with transparent wings. The female is worm-like; she lacks eyes, wings, functional legs, or mouthparts. The female never gets the chance to leave the bag she constructs as a larva. The male finds her, mates, and the female moth develops eggs inside her abdomen. These eggs (500-1000) overwinter inside the deceased female, inside her bag, and can hatch roughly around mid-June in southern New England. Like other insects with flightless females, the young larvae can disperse by ballooning (spinning a silken thread and catching the wind to blow them onto a new host).

While arborvitae and junipers can be some of the most commonly known host plants for this insect, the bagworm has a broad host range including both deciduous and coniferous hosts numbering over 120 different species. Bagworm has been observed on spruce, Canaan fir, honeylocust, oak, European hornbeam, rose, and London planetree among many others. This insect can be managed through physical removal, if they can be safely reached. Squeezing them within their bags or gathering them in a bucket full of soapy water (or to crush by some other means) can be effective ways to manage this insect on ornamental plants. Early instar bagworm caterpillars can be managed with Bacillus thuringiensis var. kurstaki (Btk) but this is most effective on young bagworms that are approximately no larger than ¾ inch in length. As bagworms grow in size, they may also have behavioral mechanisms for avoiding chemical management. At this point in the season, physical removal (if possible) may be the best option. This will also preserve any natural enemies that would be found attacking this insect, such as certain parasitic wasps. It is also important to note that the bags from dead bagworms will remain on the host plant, so check the viability of the bagworms by dissecting their bags to avoid unnecessary chemical applications. Historically in Massachusetts, bagworms have been mostly a problem coming in on infested nursery stock. With females laying 500-1000 eggs, if those eggs overwinter the population can grow quite large in a single season on an infested host. Typically, this insect becomes a problem on hedgerows or plantings nearby an infested host plant. Thyridopteryx ephemeraeformis is found from Massachusetts to Florida, and is typically a more significant pest in southern climates. However, in recent years (2019-2021), bagworm appears to be overwintering successfully in certain locations in Massachusetts.

  • Damage to the lower 6 ft. of pine from the black turpentine beetle (Dendroctonus terebrans) 8/18/2022 in Barnstable County. (Image Courtesy of: Chad Thomas.) Damage to the lower 6 ft. of pine from the black turpentine beetle (Dendroctonus terebrans) 8/18/2022 in Barnstable County. (Image Courtesy of: Chad Thomas.) Damage to the lower 6 ft. of pine from the black turpentine beetle (Dendroctonus terebrans) 8/18/2022 in Barnstable County. Note the reddish, oozing masses of pitch in response to the bark beetle attack. (Image Courtesy of: Chad Thomas.)Black Turpentine Beetle: Dendroctonus terebrans adults may begin to be active between mid-April to mid-May, however all life stages, including adults, of this insect may be found throughout the season. Host plants include: black pine (Pinus thunbergiana), eastern white pine (Pinus strobus), Japanese black pine (Pinus thunbergii), loblolly pine (Pinus taeda), pitch pine (Pinus rigida), red spruce (Picea rubens), Scots pine (Pinus sylvestris), and slash pine (Pinus elliottii).

Black turpentine beetle adults and larvae from samples collected in Barnstable County were recently submitted to the UMass Plant Diagnostics Laboratory for identification. This insect is in the same genus as the southern pine beetle (Dendroctonus frontalis) but some useful features and behaviors can be used in the field to distinguish the two from one another. First, the black turpentine beetle (5-8 mm or 5-10 mm are reported in the literature.) has much larger adults than the southern pine beetle (2-3 mm.). Second, the black turpentine beetle tends to limit its attacks of the trunk of its host plants to the lower 6 ft., whereas southern pine beetle caused popcorn-like pitch tubes may be found throughout the entire trunk of the tree. The photos included here show the pitch tubes created by black turpentine beetle activity on the lower trunk of the infested trees. (Photos courtesy of Chad Thomas, 8/18/2022, Barnstable County.)

This is one of the largest native North American bark beetles. In the northern parts of its extensive range, the black turpentine beetle overwinters as an adult in the bark of its hosts. In the southern portions of its range, all life stages may be present throughout the year. As mentioned above, egg laying and feeding is usually kept to the basal 6 feet of the host plant. Mated pairs of adult beetles work to excavate galleries that may be 9.8 inches wide and 11.8 inches long. 100-200 eggs may be laid on one side of the gallery. Once hatched, larvae feed in groups on the inner bark. Fully grown larvae are legless, white, and almost 1/2 inch in length. Pupation occurs and adults eventually emerge from the bark to re-infest the same tree, or disperse to another susceptible host.

Stumps and buttress roots of freshly cut trees are favored by this insect. Attacked trees may exhibit browning of needles and oozing of large masses of pitch. Masses of pitch (pitch tubes) may cover holes in the trunk and may be considerably larger than those of southern pine beetle. Pitch hardens and is first white but may turn red as it ages. Pitch is irregular in shape and up to 1.6 inches in diameter. Pitch tubes are not visible when the area below the soil line is attacked. Healthy trees are usually not attacked, however it has been reported on occasion.

Check drought-stressed or otherwise stressed trees for needles turning light green to rust color. Drought-stressed trees, such as what is so common currently, may be more susceptible to bark beetle attack, including from black turpentine beetle. Also avoid pruning and removal of host plants during the growing season, as these activities can be additionally attractive to the black turpentine beetle. Unless it is a safety hazard, if you are able, wait until the dormant season for these activities. (However, the importance of addressing safety hazards of course outweighs attempts to reduce attracting additional bark beetles.) Check the lower 6 feet, particularly the lower 18 inches, of the trunk for 1.6 inch in diameter pitch tubes or small entrance holes from the adults. Reddish-brown boring dust may be found near the base of the tree as well.

  • Fall Home-Invading Insects: Various insects, such as ladybugs, boxelder bugs, seedbugs, and stink bugs will begin to seek overwintering shelters in warm places, such as homes, throughout the next couple of months. While such invaders do not cause any measurable structural damage, they can become a nuisance especially when they are present in large numbers. While the invasion has not yet begun, if you are not willing to share your home with such insects, now should be the time to repair torn window screens, repair gaps around windows and doors, and shore up any other gaps through which they might enter the home.
  • Early instar fall webworm caterpillars found skeletonizing birch in Hampshire County, MA on 7/2/2022. (Photo: Tawny Simisky, UMass Extension) 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 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).

Additionally, do not forget that during drought conditions, systemic applications may prove difficult. It is important to follow proper watering practices for high value trees and shrubs in the landscape (while observing local watering restrictions). Watering after systemic applications may improve tree uptake. Follow all label instructions for safety and proper use.

  • Hickory Tussock Moth: Lophocampa caryae is native to southern Canada and the northeastern United States. There is one generation per year. Overwintering occurs as a pupa inside a fuzzy, oval shaped cocoon. Adult moths emerge approximately in May and their presence can continue into July. Females will lay clusters of 100+ eggs together on the underside of leaves. Females of this species can fly, however they have been called weak fliers due to their large size. When first hatched from their eggs, the young caterpillars will feed gregariously in a group, eventually dispersing and heading out on their own to forage. Caterpillar maturity can take up to three months and color changes occur during this time. These caterpillars are essentially white with some black markings and a black head capsule. They are very hairy, and should not be handled with bare hands as many people can have skin irritation or rashes (dermatitis) as a result of interacting with hickory tussock moth hairs. By late September, the caterpillars will create their oval, fuzzy cocoons hidden in the leaf litter where they will again overwinter. Hosts whose leaves are fed upon by these caterpillars include but are not limited to hickory, walnut, butternut, linden, apple, basswood, birch, elm, black locust, and aspen. Maple and oak have also been reportedly fed upon by this insect. Several wasp species are parasitoids of hickory tussock moth caterpillars.

  • 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.
  • 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.

  • 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.
  • Adult viburnum leaf beetles have emerged, mated, and are laying eggs near the terminal ends of their host plant twigs. Eggs are found within capped pits, as seen on 7/19/2022 in Hampshire County, MA. (Photo: Tawny Simisky, UMass Extension.) 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 .

  • The caterpillar of the white satin moth seen in Beartown State Forest (Berkshire County) on 6/8/2022. (Image Courtesy of: Eric Reynolds, MA DCR) The caterpillars of the spongy moth (left) and white satin moth (right) seen in Beartown State Forest (Berkshire County) on 6/8/2022. (Image Courtesy of: Eric Reynolds, MA DCR) 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: .

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

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