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Landscape Message: September 8, 2023

Landscape Message: September 8, 2023
September 8, 2023

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

Thanks for your continuing interest!  Note that we are now in the every-other-week period of the season, and the next message will be posted on September 22.  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 September 6, 2023. Total accumulated growing degree days (GDD) represent the heating units above a 50ºF baseline temperature collected via regional NEWA stations ( for the 2023 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

MA Region/Location

2023 Growing Degree Days

Soil Temp
(°F at 4" depth)

(Gain in inches since last report)

Time/Date of Readings

Gain since last report

2023 total









9/6/2023 12:00 PM







9/6/2023 3:00 PM







9/6/2023 9:30 AM







9/6/2023 4:00 PM







9/6/2023 6:15 AM







9/6/2023 12:30 PM







9/6/2023 12:00 PM







9/6/2023 7:00 PM








n/a = information not available


US Drought Monitor:  Despite things trending drier in the past couple of weeks, once again no drought areas are currently designated in the state of Massachusetts.  State map as of Thursday 9/7:


Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
Heptacodium miconioides (seven son flower) Full * Begin/Full Begin Begin Begin/Full Full Begin
Clematis terniflora (sweet autumn clematis) Full Begin Full Begin Begin/Full Begin/Full Full Begin/Full
Polygonum cuspidatum / Reynoutria japonica / Fallopia japonica (Japanese knotweed) Full Full/end 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 August 23 thru September 6 was 68℉ with a high of 83℉ on Sept. 3 and a low of 51℉ on Sept. 1.  Daytime highs have ranged from the upper 60s to the lower 80s and nighttime lows from the lower 50s to upper 60s. The first half of the period was dominated by cloudy days with several small precipitation events totaling about an inch and a third. The second half of the period was dominated by dry and sunny conditions. Soil moisture is adequate but approaching short. 

Herbaceous plants seen in bloom include goldenrods (Solidago spp.), asters (Symphyotrichum spp.), stonecrop (Sedum spp.) and Joe-Pye weed (Eutrochium maculatum). Woody plants observed in bloom during the period include mimosa (Albizia julibrissin), rose of Sharon (Hibiscus syriacus), hydrangeas (H. macrophylla and H. paniculata), glorybower (Clerodendrum trichotomum), and crape myrtle (Lagerstroemia indica). 


Box tree moth was recently confirmed in Barnstable County. Box tree moth is an introduced pest that feeds on boxwood and has the potential to cause extensive damage. Inspect boxwood for signs.  

Insect or insect damage observed during the period include: turpentine beetle damage to pitch pine, pine tip moth damage to pitch pine, pine weevil damage to white pine, fall webworm on sweetgum, hibiscus sawfly damage on hardy hibiscus, lacebug damage on andromeda and sycamore, and two spotted spider mite on many plants.

Disease symptoms and signs observed during the period include: beech leaf disease (BLD) on American beech; foliar nematode on hosta; cercospora leaf spot on bigleaf hydrangea; Guignardia leaf blotch on horsechestnut; cedar apple rust, apple scab and fire blight on crabapple; anthracnose on maple; pear trellis rust on callery pear; phytophthora root rot on lavender; fungal tip blight on Leyland cypress; shoot flagging on oak likely botryosphaeria; grey leaf spot on Japanese forest grass; and powdery mildew on many herbaceous and woody plants.

Weeds in bloom include: spotted spurge (Euphorbia maculata), purslane (Portulaca oleracea), lambsquarters (Chenopodium album), Pennsylvania smartweed (Polygonum pensylvanicum), ragweed (Ambrosia artemisiifolia), and crabgrass (Digitaria spp.).

Yellowjackets, wasps, and bald faced hornets have become more noticeable as they seek out sugary food resources. Mosquitoes have also become more noticeable

Southeast Region (Dighton)

General Conditions:

It feels like hurricane-season weather. One week it's cool and rainy, the next it's hot and humid. Monday, September 4th, and Tuesday the 5th posted the highest temperatures of the last two weeks at a steamy 88°F on both days. The low of 48°F on the morning of the previous Saturday, September 2nd felt chilly enough for a sweater once more. The average temperature over the period was 60°F. Rains on Friday, August 24 through Saturday, August 25 resulted in 1.25 inches of precipitation. 

Plants in flower: Buddleia davidii (butterfly bush), Campsis radicans (trumpet vine), Clematis paniculata (sweet autumn clematis), Hibiscus syriacus (rose-of-Sharon), Hydrangea paniculata (panicle hydrangea), Polygonum cuspidatum (Japanese knotweed), Vitex agnus-castus (chastetree).


Gardeners are usually thankful for the rain. After last summer's ferocious heat and drought, complaining about too much moisture makes a person sound like an ingrate but the evidence speaks for itself. Mildew and fungus are rampant. 

North Shore (Beverly)

General Conditions:

Temperatures during this reporting period were variable. The first half of this period was relatively cooler with day temperatures ranging from the low 70s to high 70s, and night temperatures from the low 50s to low 60s. Day temperatures in the second half of the period ranged from the low 80s to mid 80s and night temperatures from the low 60s to low 70s. The average daily temperature was 68℉ with the maximum temperature of 84℉ recorded on September 5 and the minimum temperature of 49℉ recorded on September 1. Rain storms came through on two separate days and brought a significant amount of rainfall. Approximately 3.46 inches of rain were recorded at Long Hill during this period. Woody plants seen in bloom include: Franklin tree (Franklinia alatamaha), seven-son flower (Heptacodium miconioides), blue beard (Caryopteris × clandonensis), and panicle hydrangea (Hydrangea paniculata). Herbaceous plants seen in bloom include: Joe-Pye weed (Eutrochium purpureum), garden phlox (Phlox paniculata), hostas (Hosta spp.), ‘Autumn Joy’ stonecrop or sedum (Hylotelephium telephium), black-eyed Susan (Rudbeckia hirta), New England aster (Symphyotrichum novae-angliae), Japanese anemone (Anemone x hybrida), and coneflower (Echinacea spp.). Various kinds of annuals are also contributing color to the landscape.


Damage by slugs was observed on hostas. The population of slugs has been high due to the continued moist conditions on the ground. Also observed this period is an increased number of areas with a crumbly soil appearance, like coffee grounds. These are the castings of invasive jumping worms. It seems like the population of jumping worms is higher this year compared to last year. Crabgrass and other weeds such as prostrate spurge (Euphorbia maculata), horseweed (Conyza canadensis), ragweed (Ambrosia artemisiifolia), and Japanese knotweed (Polygonum cuspidatum) are thriving in the landscape. Goldenrod (Solidago canadensis) is in full bloom and is providing a lot of color on roadsides and meadows. Ragweed (Ambrosia artemisiifolia) is also in bloom, making it difficult for allergy sufferers. Mosquitoes and ticks are still very active.

East (Boston)

General Conditions:

August came to an end feeling like early fall and September arrived feeling like mid-summer. The average daytime temperature over the two week reporting period was 79℉. The last week of August daytime temperatures averaged 76℉ while the first week of September averaged 84℉, including four consecutive days in the 80’s. Overnight lows were fairly consistent, averaging 60℉ and 62℉ respectively. Total rainfall for August was 4.17 inches. We have yet to record any precipitation in September as of the 6th. Caryopteris x clandonensis (bluebeard), Heptacodium miconioides (seven son flower), and Symphyotrichum novae-angliae (New England aster) are flowering.


Fungal leaf spot continues to be prevalent throughout the landscape. Common ragweed (Ambrosia artemisiifolia), yellow nutsedge (Cyperus esculentus), and Japanese knotweed (Polygonum cuspidatum) are flowering. Recent transplants will require supplemental irrigation due to lack of early September precipitation.

Metro West (Acton)

General Conditions:

The Labor Day holiday weekend has come and gone, which unofficially marks the end of the summer season and typically brings with it cooler nighttime and pleasant daytime temperatures. As I write this on Tuesday the 5th, my thermometer reads 89°, hardly cooler temperatures. The historical monthly average rainfall for August is 3.72” and we closed out the month with a total of 8.41” recorded for this area. September’s average rainfall is 3.77” and a mere 0.001” has been recorded as of the 5th for this month. Signs of fall are visible in the landscape and soon enough the fall equinox will be here, arriving on September 23rd. Some Prunus (cherry) and Acer (maple) are exhibiting early fall color. 


There has not been any significant rain recorded for this month so far. Let’s hope that we receive more rain now that the fall planting season is upon us. Observed in the landscape this past two weeks were leaf blotch on Aesculus spp. (horsechestnut); powdery mildew on Cornus florida (dogwood), C. sericea (red twig dogwood), Hamamelis (witch hazel), Monarda (bee balm), Phlox, and Syringa (lilac); and cedar apple rust on Amelanchier spp. (serviceberry) and Crataegus spp. (hawthorn).

Central Region (Boylston)

General Conditions:

Aside from the last few days of the reporting period, the unofficial end of summer was rather pleasant, with lower temperatures than we generally expect at the end of August, and surprisingly little rain. August 25 was the coolest day during the two week stretch, with a high temperature of just 70℉. Temperatures were consistently in the 70’s, with a spike into the high 80’s to start this week. The last significant precipitation was recorded on August 30, and as a result, newly planted landscape plants are in need of supplemental irrigation. Soil moisture levels are still adequate for most established plants. Fall blooming asters and goldenrods are starting to bloom, and some trees, especially in wetland areas, are starting to show fall color.


Signs and symptoms of beech leaf disease are becoming more widespread throughout the region, especially on American beech (Fagus grandifolia). Trees that were healthy earlier in the season are now showing the trademark interveinal banding and some trees have been nearly defoliated as the disease is progressing. Also spotted this reporting period was magnolia scale. During this time of year, female scale give birth to live young. The crawler stage is more susceptible to control measures, so this is the time of year to attempt control.

Pioneer Valley (Amherst)

General Conditions:

Some intense late season heat and humidity has kept summer alive and well in the Pioneer Valley. Heat index values in the upper 90s were expected from 9/5 through 9/7 with high humidity expected to continue through 9/10 with minimal relief from scattered thunderstorms. The tri-counties experienced two rain events over this past reporting period on 8/25 and 8/30. Accumulations from these two storms ranged from ~0.75” to 2”, with Franklin County receiving the higher totals. Subsurface soil moisture remains good but the uppermost soils in exposed, sunny locations are drying out. Established trees and shrubs have ample soil moisture as we endure this blast of early September heat. However, recently transplanted trees and shrubs should be closely monitored to maintain good moisture in the root zone. Prior to the heat, there were some pleasant late summer days with daytime temperatures in the 70s and lows in the 50s.    


The elm zigzag sawfly (Aproceros leucopoda) was recently detected in both Hampden and Berkshire Counties. This non-native pest is capable of defoliating elms; more information, including links to photos, can be found at and info from MDAR on where to report suspected finds at A distinctive symptom of infestation is the zig-zag pattern of defoliation made by the sawfly larvae. Feeding occurs between the primary leaf veins (interveinal). At present, elms may also have scattered defoliation in the canopy from Japanese beetles (Popillia japonica). This ubiquitous pest also feeds on interveinal leaf tissue, but the primary and secondary veins remain intact, giving infested leaves a skeletonized appearance. As badly injured as Japanese knotweed (Polygonum cuspidatum) was after the 5/18 frost, it’s currently basking in full flower with no lingering effects. The season-long activity of Asian jumping worms (Amynthas agrestis) is very conspicuous right now and beds harboring these invasive pests may need additions of organic matter (compost, bark mulch, leaf mulch, etc.) to compensate for its rapid breakdown. Hawthorns in shaded settings on the UMass campus are almost completely defoliated from Entomosporium leaf spot. Horsechestnuts appear awful, as they always do this time of year, due to Guignarida leaf blotch. Early color change continues for scattered hardwoods, especially for sugar maples with abundant seed in the canopy. Mast years for maples can result in undersized foliage and for trees with maple anthracnose, foliage may be shed prematurely. Diplodia and Botryosphaeria canker are very abundant on a range of different hardwoods and conifers at this time, especially crabapples. Pear trellis rust (Gymnosporangium sabinae) was observed on a pear (Pyrus communis). This disease is characterized by large, orange-yellow leaf spots on the upper leaf surface with tan-colored, gall-like tissue on the underside that can be confused with insect activity. The black-staining polypore, Meripilus sumstinei, has been located around the base of deciduous hardwoods. Its presence does not indicate serious root or lower trunk rot is present. Spruce spider mites (Oligonychus ununguis) were found on lower and interior canopy needles of Norway spruce. The abundant rainfall this season likely suppressed outbreaks this season (heavy rain easily washes spider mites from infested needles), but new populations can quickly develop during dry periods in the autumn season.

Berkshire Region (West Stockbridge)

General Conditions:

Hazy, hot, and humid best describe the weather conditions of late. This is a bit unusual, given that we are a little more than two weeks from the autumnal equinox (September 23). Despite the heat, soil moisture is at a good level and rain is expected over the next few days. This promises decent conditions for fall planting of most landscape plants as well as seeding lawns. Turfgrass growth is rapid at this time. Managed and natural landscapes are bright with many late season bloomers putting on a colorful show. Weather-wise for the past two weeks (August 23 – September 5), conditions at the 3 NEWA sites in Berkshire County were as follows. Highest temperatures over the scouting period occurred on September 5: 88℉ in North Adams, 85℉ in Pittsfield and Richmond. Lowest temperatures all occurred on September 1st: 44℉ in Richmond, 45℉ in Pittsfield, and 47℉ in North Adams. These cool temperatures in the 40's did not last long as many sites in the Berkshires could have record high temperatures by the end of this week.


Few pests were found during scouting. There appears to be more damage to landscape plants from browsing by deer and rabbits at this time than from insects. However, the slug and snail populations are high and also account for much damage to herbaceous plant foliage. A few Japanese beetles are hanging on and feeding on tender foliage of vines and some herbaceous perennials. Evidence of magnolia serpentine leafmining caterpillar (Phyllocnistis magnoliella) was found at one of the scouting sites. The number of dead or dying white ash (Fraxinus americana) due to the emerald ash borer (Agrilus planipennis) is steadily increasing and one wonders about the long-term fate of the ash tree in Berkshire forests. Mosquitoes and gnats are overwhelming and making outdoor labor quite uncomfortable. The biggest problem with regard to plant health at this time is the preponderance of foliar diseases. Leaf spot diseases in particular are extremely common on trees and shrubs, causing much premature leaf drop. Powdery mildew and other leaf diseases, e.g. peony leaf blotch caused by the fungus Graphiopsis chlorocephala, are frequently observed on herbaceous perennials. 

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

Seiridium canker (Seiridium sp.) on Leyland cypress (×Cupressocyparis leylandii). In a hedgerow of several mature trees (approximately 20-years-old), one tree is long dead while another is exhibiting dieback throughout 75% of the canopy. The trees receive full sun in sandy loam soils with moderate drainage. The managing arborist notes the trees are very tightly trimmed. Seiridium canker is a serious disease of members of the Cupressaceae across the northern and southern hemispheres. In the northeastern U.S., the pathogen is primarily found on Leyland cypress, a conifer that seems to be in perpetual taxonomic flux (currently in genus ×Cupressocyparis). The disease is characterized by girdling twig and branch cankers that result in browning needles and a progressively worsening dieback of the canopy. Infected twigs and branches may exhibit weeping resin, cracked and splitting bark, and sunken lesions with darkly discolored bark. However, in many cases these symptoms are nuanced and may not be visible. Excessive pruning, drought stress and winter injury are primary sources of stress that readily facilitate disease development and spread.

Leaf distortion and stunting on European beech (Fagus sylvatica) that does not appear to be related to beech leaf disease (BLD). Trees of various ages from differing properties have shoots with undersized and distorted foliage adjacent to leaves that appear otherwise healthy. Some canopies appear thin with varying levels of dieback. There is no banding or convex cupping that is typical of BLD-infested beech and attempts to isolate the BLD nematode from the foliage have been negative. Nearly all the trees have some level of woolly beech aphid (Phyllaphis fagi) infestation, but this pest is mostly cosmetic and likely unrelated to the stunting and distortion.

Needle and browning and branch dieback of Wichita Blue juniper (Juniperus scopulorum 'Wichita Blue') caused by Diplodia mutila and Pestalotiopsis. The tree is less than 10-years-old and was transplanted three years ago to a residential garden. It receives full sun on a slight slope with drip irrigation but is exposed to strong westerly winds. It was planted into a good layer of loam (~9”) over clay. In late spring, needles at the branch tips started to brown and the dieback has worsened over time to consume entire branches. The submitted branch segments had needles that were very pale green to light brown with evidence of cankering that included stained vascular tissue and erumpent pads of fungal tissue swelling underneath the bark surface. Diplodia mutila has a broad host range among conifers and hardwoods, causing girdling twig and branch cankers. Pestalotiopsis attacks foliage, twigs and small branches, often as an opportunistic pathogen of weakened and stressed trees. This fungus is very common on a variety of Juniperus species across the managed landscape.

Scattered twig dieback in the canopy of a Korean mountain-ash (Sorbus alnifolia) due to infection by Diplodia. Photo by N. Brazee Diplodia twig canker of Korean mountain-ash (Sorbus alnifolia). A group planting of three trees on the UMass campus that are approximately 8” in diameter and 20–30’ tall. In early August, a twig blight scattered throughout the canopy was observed (see photo). The blackened leaves and twigs contrast sharply with adjacent healthy twigs throughout the canopy. The blighted twigs are more concentrated in the lower canopies, but all trees are diseased. Incubation and microscopic analysis of the infected twigs revealed the cankering pathogen Diplodia was responsible. Diplodia and Botryosphaeria cankering has been very abundant this year on other members of the rosaceae, including crabapple, apple, and hawthorn.

Scattered shoot tip dieback in the canopy of an umbrella pine (Sciadopitys verticillata) due to suspected overwatering. The tree is approximately 25-years-old and has been present at the site for 20 years. It receives part-sun and resides in a crowded planted bed with a mulched base and drip irrigation in sandy loam soils. The submitted shoot tips were wilted with pale green, shriveled needles. Upon microscopic evaluation, there was no indication of any insects or disease from the stems and needles. The drip irrigation is run every other day for 23 minutes and the local area has received >9” of rain from July 1 to August 31. For an established tree, this amount of natural rainfall over a two-month period is sufficient to maintain healthy growth and supplemental water is not necessary. Overwatering symptoms in conifers can include yellow to pale green needles, premature needle shedding and branch dieback. 

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

Insects and Other Arthropods

Interesting Insects Reported Recently:

  • A katydid viewed on 8/13/2023 in Hampshire County, MA. Photo: Tawny Simisky, UMass Extension. Katydids: insects in the family Tettigoniidae are referred to as katydids, due to the sounds certain species make when communicating (each species has their own unique way of communicating, and not all katydids sound like they are saying “Katy did, Katy didn’t!” on repeat). They are closely related to the crickets and grasshoppers, and as such another common name for these insects are bush crickets. Many species are green and well camouflaged to hide in nearby plants and are seldom seen and more often heard (they are typically found in trees and not on the ground). On occasion, a pink katydid is seen with much excitement. Katydid females lay their eggs on the soil, plant stems, or on tree bark. The egg stage overwinters. Eggs hatch and nymphs emerge, which eventually develop into adults. (Katydids have incomplete metamorphosis, so no pupal stage occurs.) Most katydids feed on plant material, but rarely cause any notable or noticeable damage to their host plants. As such, these insects should be preserved in our landscapes.
  • A stinging nettle caterpillar found in Essex County, MA on 8/16/2023. Photo courtesy of David Larson. Stinging Nettle Caterpillar: Monema (Cnidocampa) flavescens caterpillars are brightly colored with conspicuous markings, warning other organisms that the caterpillars also possess well developed urticating spines found on fleshy horns. Caution: the spines of these caterpillars can cause a reaction similar to touching stinging nettle plants. They should not be handled. The caterpillar in this photo was reported to UMass Extension from Essex County, MA on 8/16/2023 courtesy of David Larson.

Caterpillars, once mature, spin hard cocoons often found in the forks of smaller twigs of their host plants. Cocoons may look like buds on the plant or bark and blend in and are white and gray-brown in color. It is thought that the cocoons of this non-native species were accidentally introduced into a suburb of Boston, MA around 1906. The pupal stage is the overwintering stage, with adult moths emerging in the spring. Fernald reported adult moths emerging in Massachusetts in late June, early July. Adults are active for a short period, and do not feed. Female moths lay their elliptical, flattened, and transparent eggs singly on the undersides of host plant leaves. Caterpillars feed on the leaf undersides initially, but eventually eat the entire leaf, except for the midrib and main veins, from the tip as they grow in size. Eight instars of caterpillars have been observed for this insect (Dyar, 1909). Larvae have been reported in Massachusetts from late July to October, pupae from May to June, and adults from late June to early August (Schaffner, 1959).

The stinging nettle caterpillar is a very obscure insect that is rarely seen in a limited portion of eastern Massachusetts. Caterpillars may feed on the foliage of many hardwoods but mostly Norway maple, sycamore, apple, and hawthorn. More recently it has been confined to about a 30-mile radius around Boston, Massachusetts and has not been seen until limited reports of finding the caterpillars have been made in recent years (Topsfield, MA, 2019; The Caterpillar Lab). The largest extent of the distribution of this insect around Boston may have been in 1942 when an approximately 300 square mile radius was reported (Dowden, 1946).

  • Winter cutworm eggs seen on beech on 8/28/2023. Photo courtesy of Tom Ingersoll. Winter cutworm eggs seen on beech on 8/28/2023. Photo courtesy of Tom Ingersoll. Very minor feeding by winter cutworm caterpillars seen on beech on 8/28/2023. Management is not necessary. Photo courtesy of Tom Ingersoll. Winter Cutworm Eggs: the eggs of Noctua pronuba or the winter cutworm (caterpillar stage) or the large yellow underwing (moth stage) have been found for the last few weeks on various landscape ornamental and shade trees and shrubs, along with other surfaces (ex. garden ornaments). See photos of the winter cutworm eggs viewed on beech on 8/28/2023 courtesy of Tom Ingersoll. This (until now) mysterious appearance of eggs, followed by very minor feeding on leaves (if laid on leaves) and apparent disappearance of the culprit has occurred this time of year for the last few seasons. Until now, with the help of Charley Eiseman and Whitney Cranshaw, the identity of the eggs has remained unknown. The winter cutworm is a non-native insect that may feed on a variety of plants in the landscape. Larvae mature by the winter and can be seen on mild days in the snow! Pupation is believed to occur in the spring, with adults found in the spring and again in the late summer. There may be two generations per year, but the life cycle of this insect is not completely understood. Increasingly, winter cutworm caterpillars are reported in Massachusetts throughout the winter season (see the Insects section under Turf in the April 7, 2023 issue of the Landscape Message). The good news is, even though the eggs of this species have been observed on beautyberry, beech, and Japanese white pine in ornamental landscapes this year, no significant feeding damage has been seen on these plants. In most cases, although noticeable, the egg masses can be ignored or tolerated. More information about winter cutworm is available at:

Current Nuisance Problems of Note:

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.

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

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

Click here for more information about mosquitoes in Massachusetts.

EEE and WNV testing and tracking for this season began on June 12, 2023. The Massachusetts Department of Public Health tracks animal cases, human cases, and mosquito positive samples from traps from June through October in Massachusetts. The first West Nile Virus positive mosquito sample was collected on July 6, 2023, in the town of Brookline in Norfolk County, MA. Click here for more information.

As of September 1, 2023, 96 positive WNV mosquito samples have been collected in the state. See the preceding link for specific locations.

The first two human cases of West Nile virus (WNV) have been reported in Massachusetts as of 8/29/2023:

The first eastern equine encephalitis (EEE) positive mosquito samples for 2023 were detected in Massachusetts as of 9/1/2023:

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

Click here for more information about mosquito repellents.

  • Wasps/Hornets: Many wasps are predators of other arthropods, including pest insects such as certain caterpillars that feed on trees and shrubs. Adult wasps hunt prey and bring it back to their nest where young are being reared, as food for the immature wasps. A common such example are the paper wasps (Polistes spp.) who rear their young on chewed up insects. They may be seen searching plants for caterpillars and other soft-bodied larvae to feed their young. Paper wasps can sting, and will defend their nests, which are open-celled paper nests that are not covered with a papery “envelope”. These open-celled nests may be seen hanging from eaves or other outdoor building structures. Aerial yellow jackets and hornets create large aerial nests that are covered with a papery shell or “envelope”. Common yellow jacket species include those in the genus Vespula. Dolichovespula maculata is commonly known as the baldfaced hornet, although it is not a true hornet. The European hornet (Vespa crabro) is three times the size of a yellow jacket and may be confused for the northern* giant hornet (Vespa mandarinia). The European hornet is known to Massachusetts, but the northern giant hornet is not. European hornets have black, tear-drop shaped markings on their abdomens, but northern giant hornets do not. If you are concerned that you have found or photographed a northern giant hornet, please report it here: articles in the news have homeowners concerned about a new invasive species of hornet that is closely related to the northern giant hornet. The yellow-legged hornet (Vespa velutina) has been detected in Georgia as of August 2023. The yellow-legged hornet is native to Southeast Asia and smaller than the northern giant hornet. There is concern that the yellow-legged hornet, if allowed to establish in the USA, could pose a threat to honeybee health. More information can be found here: . If you suspect you’ve seen the yellow-legged hornet in Massachusetts, take a photo and submit a report 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.

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

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

Highlighted Invasive Insects & Other Organisms Update:

  • Box tree moth 1 (MDAR) Box tree moth injury (MDAR) Box Tree Moth: staff with the Mass. Dept. of Agricultural Resources (MDAR) and the USDA have recently confirmed several instances of boxwood shrubs on Cape Cod that were infested with the invasive pest known as box tree moth (Cydalima perspectalis). The finds have all been in established plantings (2 years old or more). It is unclear how the moths were introduced to the area or how widespread this pest is; USDA is currently working to delimit the infestation.

The main host of box tree moth is boxwoods (Buxus spp.), though in their native range, the moths will also attack burning bush (Euonymus alatus) and a few other uncommon species, if boxwood is not available. The late-stage caterpillars cause significant defoliation and should be detectable now: check boxwoods for greenish brown caterpillars, 1 to 1.5 inches long, with black stripes running from head to tip, black heads, and long hairs scattered along the body. The caterpillars form webbing in the boxwoods to protect themselves, and in a heavy infestation this webbing fills up with visible clumps of frass pellets (waste material).

Box tree moths can cause complete defoliation of boxwoods, eventually killing entire shrubs. We encourage you to review the following fact sheet from the USDA to learn more about this pest, including how to recognize the adult moths, caterpillars, and eggs: Box Tree Moth Pest Alert

If you grow, sell, or install boxwoods, please inspect them for any signs of this pest, and report any finds to

More information about box tree moth, including management options, is now available from UMass Extension at:

  • Elm zigzag sawfly feeding on an elm leaf viewed in Berkshire County, MA on 8/16/2023. Photo courtesy of: Nicole Keleher, MA DCR Forest Health Program. Elm zigzag sawfly feeding damage and cocoon on sample collected from Berkshire County, MA on 8/10/2023. Photo courtesy of: Eric Reynolds, MA DCR Forest Health Program. Elm zigzag sawfly defoliation viewed in Berkshire County, MA on 8/16/2023. Photo courtesy of: Nicole Keleher, MA DCR Forest Health Program. Elm Zigzag Sawfly: (Aproceros leucopoda) is a nonnative insect that originated in eastern Asia (Japan and certain regions of China). It is now invasive in Europe (2003) and North America. The elm zigzag sawfly has been found in Virginia (2021), Maryland, Pennsylvania, North Carolina, New York, and Vermont. In 2023, the elm zigzag sawfly was detected for the first time in a small, forested area of Berkshire and Hampden Counties in Massachusetts: Significant defoliation of elm host plants was seen at the impacted locations. It is currently unclear how widespread the elm zigzag sawfly is in Massachusetts or how the infestation was introduced. 

Female elm zigzag sawflies cause a tiny amount of damage to the edges of host plant leaves as they lay their eggs. Tiny scars are formed as a result of female egg laying. Eggs hatch and young sawfly caterpillars (the most destructive life stage of the insect) begin their characteristic zig-zag patterned feeding. These zig-zag shaped notches in the leaf can extend 5-10 mm into the leaf from the edge. Multiple caterpillars can feed on a single leaf. Entire leaves can be completely stripped, leaving only the veins behind. Heavily infested trees can suffer partial or complete defoliation.

If you suspect you have found elm zigzag sawfly in Massachusetts, please report it to Nicole Keleher (Massachusetts Department of Conservation and Recreation, Forest Health Program),, or to the MA Dept. of Agricultural Resources at

More information about the elm zigzag sawfly, including management options, is now available from UMass Extension at:

  • Southern Pine Beetle: Dendroctonus frontalis has been collected in traps in Massachusetts and other parts of New England in recent years. Historically, the southern pine beetle has been native to the southeastern United States, however its range is moving northward due to warming winters and climate change. The Massachusetts Department of Conservation and Recreation (DCR) Forest Health Program, has announced that they have detected the first pocket of southern pine beetle killed trees (pitch pine, Pinus rigida) in Massachusetts on Nantucket. This is the first observation of this species killing trees in the state. An active infestation of southern pine beetle was found killing trees in July and MA DCR is working with the property owner to determine next steps and potential management options at the site. If you believe you have detected southern pine beetles in trees in Massachusetts, please contact Nicole Keleher, MA DCR Forest Health Director, at: More information about southern pine beetle is also available from MA DCR at .

The southern pine beetle (SPB) undergoes complete metamorphosis (is holometabolous) with four life stages: egg, larva, pupa, and adult. Adults are dark red/brown to black in color and 1/16 – 1/8” in length. Eggs are white and larvae are crescent-shaped with a dark red/brown head and a white body. Four larval instars are present, with pupa being bright white. The adult is light brown in color prior to drying and hardening and becoming darker in color. Female beetles select suitable host trees and release chemical pheromones to attract male mates. She will penetrate the bark and begin creating a gallery where she is joined by the male and mates. Early attacks to the tree may be “pitched out” by the resin defenses of the tree. The pheromones produced by the females and the volatile chemicals expressed by the stressed host plant attract additional males and females. If tree defenses can be overcome, females will colonize beneath the bark, creating S-shaped galleries. The inoculation of the tree with a blue stain fungus as well as other fungi occurs with colonization of southern pine beetle, however, it is the act of "mass attack" by the insects themselves which leads to tree mortality. Entomocorticium spp. symbiotic fungi are associated with southern pine beetles and the immature larvae feed on this fungus. Females may lay up to 160 eggs in their lifetime and development can take as little as 26 days in warmer climates. In the South, 3-9 generations of SPB have been observed to occur per year. In NY, 3-4 generations have been observed on Long Island. Current Massachusetts temperatures should keep the number of generations per year to the lower end of this range.

Southern pine beetle can be detected most easily by the presence of popcorn-sized pitch tubes on the outer bark of trunks and branches. Pitch tubes can range in color from white to red. They can occur from ground level to high in the canopy of the tree. Exit holes (about 1/16” in diameter) can be observed in the bark from emerging adults. S-shaped galleries can also be observed by peeling back any bark that may be falling off the tree. Brown-orange frass (excrement) that looks like wood shavings is found packed within the galleries. By the time foliage fades from green to yellow to brown, the infestation may be advanced. The presence of certain checkered or clerid beetles can also indicate high populations of southern pine beetle, as these checkered beetles prey upon SPB. Southern pine beetle prefers trees damaged by lightning strikes or fire. In the southeastern part of the insect's range, southern pine beetle is not known to preferentially attack drought stressed or chronically stressed trees. Trees under 15 years of age or 2 inches in diameter may be seldom attacked.

  • Spotted Lantern Fly egg masses (T. 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. It overwinters as an egg mass, which the adult female insect lays on just about any flat surface. Pictures of egg masses can be seen here.

Eggs have hatched and spotted lanternfly will pass through four nymphal instars before maturing into the adult life stage. Adults are typically present by late July and the beginning of August.

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

For More Information:

From UMass Extension:

*New*: Spotted Lanternfly Management Guide for Professionals

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

Spotted Lanternfly Fact Sheet

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

From the MA Department of Agricultural Resources (MDAR):

Spotted Lanternfly Fact Sheet and Map of Locations in MA

Spotted Lanternfly Management Guide for Homeowners in Infested Areas

*New*: Spotted Lanternfly Look-alikes in MA

*New*: Spotted Lanternfly Egg Mass Look-alikes

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

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

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

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

  • Adult Emerald Ash Borer (T. Simisky)Emerald Ash Borer: (Agrilus planipennis, EAB) has been detected throughout much of Massachusetts and it was recently detected for the first time in Barnstable County. A map of these locations across the state is provided by the MA Department of Conservation and Recreation at

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

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

For More Information, see these UMass Extension Fact Sheets:

Earthworms in Massachusetts – History, Concerns, and Benefits

Jumping/Crazy/Snake Worms – Amynthas spp.

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

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

Tree & Shrub Insect Pests (Native and Invasive):

  • Ailanthus Webworm: Atteva aurea (formerly A. punctella) is a tropical ermine moth from the family Attevidae. While they may be referred to as tropical, apparently the moths themselves can tolerate much colder temperatures than their original host plants. Prior to 1784 when tree of heaven (Ailanthus altissima) was introduced into Philadelphia, PA, the ailanthus webworm was restricted to southern Florida and points south. It would appear that this restriction in distribution was due to the distribution of their original host plants in the genus Simarouba. Once tree of heaven’s range extended from the north to the south including Florida, the moths were able to move northward on the newly available and suitable host plant. Larvae of this moth feed almost exclusively on tree of heaven in the northern parts of its expanded range. Occasionally, these caterpillars will defoliate tree of heaven, but not to the extent that they could provide any form of control of this invasive tree (on younger plants, sometimes caterpillars can completely defoliate the trees and strip the bark off of small branches). Larvae cluster together in a loose web. Larvae of the ailanthus webworm have five white longitudinal lines on an olive-brown colored base with sparsely hairy bodies. Caterpillars are found in the late summer. Larvae pupate within their webs; moths emerge, mate, and then lay their eggs on the outside of the webs. Multiple overlapping generations can occur per year.
  • Andromeda Lace Bug: Stephanitis takeyai is most commonly encountered on Japanese Andromeda. Eggs are tiny and inserted into the midveins on the lower surface of the leaf and covered with a coating that hardens into a protective covering. 5 nymphal stages are reported. Nymphs are different in appearance from the adults, often covered with spiky protrusions. 3-4 generations per year have been observed in New England, with most activity seen between late-May into September (starting at approximately 120 GDD’s, Base 50°F). Both nymphs and adults can be seen feeding on leaf undersides. Adults have delicate, lace-like wings and what appears to be an "inflated hood" that covers their head. Adults are approximately 1/8 of an inch long. Arrived in the US in Connecticut in 1945 from Japan (Johnson and Lyon, 1991).

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

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

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

  • Bagworm bag (T. Simisky)Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs. This insect overwinters in the egg stage, within the bags of deceased females from last season. Eggs may hatch and young larvae are observed feeding around mid-June, or roughly between 600-900 GDD’s. Newly hatched and feeding bagworm caterpillars are small and less likely to be noticed. By late July and August, these caterpillars will be large and their feeding noticeable on individual trees and shrubs. Bagworm caterpillars were observed in abundance feeding on columnar hornbeam planted approximately 5 years ago in Amherst, MA on 7/19/2023 and reported by Alan Snow, Tree Warden, Town of Amherst. The tree was almost completely defoliated, with brown leaves looking as if they were scorched by fire. Approximately ½ inch long caterpillars littered the ground beneath the tree and could be seen climbing up the trunk or dangling from branches on silken threads. Continue to monitor susceptible host plants for bagworm caterpillars into August.

Browned and fed upon leaves of columnar hornbeam viewed in Amherst, MA on 7/19/2023 with a severe infestation of bagworm caterpillars. Photo: Tawny Simisky, UMass Extension. A columnar hornbeam viewed in Amherst, MA on 7/19/2023 with a severe infestation of bagworm caterpillars. Photo: Tawny Simisky, UMass Extension. Approximately ½ inch long bagworm caterpillars within their bags seen beneath a severely infested columnar hornbeam viewed in Amherst, MA on 7/19/2023. Photo: Tawny Simisky, UMass Extension. Bagworm caterpillars crawling up the trunk of a columnar hornbeam viewed in Amherst, MA on 7/19/2023. Photo: Tawny Simisky, UMass Extension.






  • 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 sure up any other gaps through which they might enter the home.
  • Fall Webworm: Hyphantria cunea is native to North America and Mexico. It is now considered a world-wide pest, as it has spread throughout much of Europe and Asia. (For example, it was introduced accidentally into Hungary from North America in the 1940’s.) Hosts include nearly all shade, fruit, and ornamental trees except conifers. In the USA, at least 88 species of trees are hosts for these insects, while in Europe at least 230 species are impacted. In the past history of this pest, it was once thought that the fall webworm was a two-species complex. It is now thought that H. cunea has two color morphs – one black headed and one red headed. These two color forms differ not only in the coloration of the caterpillars and the adults, but also in their behaviors. Caterpillars may go through at least 11 molts, each stage occurring within a silken web they produce over the host. When alarmed, all caterpillars in the group will move in unison in jerking motions that may be a mechanism for self-defense. Depending upon the location and climate, 1-4 generations of fall webworm can occur per year. Fall webworm adult moths lay eggs on the underside of the leaves of host plants in the spring. These eggs hatch in late June or early July depending on climate. Young larvae feed together in groups on the undersides of leaves, first skeletonizing the leaf and then enveloping other leaves and eventually entire branches within their webs. Webs are typically found on the terminal ends of branches. All caterpillar activity occurs within this tent, which becomes filled with leaf fragments, cast skins, and frass. Fully grown larvae then wander from the webs and pupate in protected areas such as the leaf litter where they will remain for the winter. Adult fall webworm moths emerge the following spring/early summer to start the cycle over again. 50+ species of parasites and 36+ species of predators are known to attack fall webworm in North America. Fall webworms typically do not cause extensive damage to their hosts. Nests may be an aesthetic issue for some. If in reach, small fall webworm webs may be pruned out of trees and shrubs and destroyed. Do not set fire to H. cunea webs when they are still attached to the host plant.
  • 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 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.
  • Mimosa Webworm: Homadaula anisocentra was first detected in the United States in 1940 in Washington, D.C. on its common namesake host plant. Originally from China, the mimosa webworm is primarily a pest of honeylocust (Gleditsia triacanthos; including thornless cultivars). This insect is found throughout the eastern and midwestern states and California. In the warmer parts of its range in the United States, it has historically heavily attacked mimosa where it grows. Adults are moths that are silvery gray in color with wings interrupted by black dots. Moths are approximately 13 mm in size (wingspan). Fully grown larvae reach up to 16 mm long and are variable in color from gray to brown with five longitudinal white stripes. Once mature, the caterpillars move to the bark scales of their host plants and find sheltered places to pupate. They may also be found in the leaf litter beneath host plants, pupating in a cocoon. Pupae are yellowish brown, 6 mm long, and encased in a white cocoon. Adult moths may emerge in early-mid June and lay gray eggs on the leaves of their hosts that turn a rose color just prior to hatch. Eggs hatch and feeding caterpillars web the foliage together, feeding within the web for protection. Larvae may be found feeding together in groups, in which case larger and aesthetically displeasing webs may be created. If disturbed, the larvae may move quickly and can drop from the web on a line of silk. A second generation of moths may occur, with pupation happening and adults emerging by August in warmer locations. In New York and New England, it is likely that this second generation emerges in September and any offspring may be killed with the winter. In the warmest parts of this insect's introduced range in the United States, three generations may be possible per year.

The larvae (caterpillars) of this insect tie the foliage of their hosts together with silken strands and skeletonize the leaves. Injury to host plant leaves may be noticeable by early July in Massachusetts. Foliage can appear bronzed in color from the feeding. Webbing usually begins at the tops of trees. An entire tree may become covered in the webs created by these caterpillars. So much webbing can often make it difficult to assess the extent of the defoliation or damage caused on an individual host. 

Certain cultivars of honeylocust may vary in their susceptibility to this insect. Gleditsia triacanthos 'Sunburst' was highly susceptible to attack in Indiana. Cultivars such as 'Moraine', 'Shademaster', and 'Imperial' may be less susceptible - however, they are still able to be fed upon by this insect, so annual monitoring may be necessary.

  • Larval feeding by the viburnum leaf beetle (Pyrrhalta viburni) is apparent in areas where this insect has become established in Massachusetts at this time. Damage to host plant leaves photographed in Berkshire County, MA on 6/5/2023. (Photo courtesy of: Tom Ingersoll.) Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. By 2008, viburnum leaf beetle was considered to be present throughout all of Massachusetts. Larvae are present and feeding on plants from approximately late April to early May until they pupate sometime in June. Adult beetles emerge from pupation by approximately mid-July and will also feed on host plant leaves, mate, and lay eggs at the ends of host plant twigs where they will overwinter. This beetle feeds exclusively on many different species of viburnum, which includes, but is not limited to, susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum, and V. rafinesquianum. Some viburnum have been observed to have varying levels of resistance to this insect, including but not limited to V. bodnantense, V. carlesii, V. davidii, V. plicatum, V. rhytidophyllum, V. setigerum, and V. sieboldii. More information about viburnum leaf beetle may be found at and at

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

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

Landscape Weeds

Japanese knotweed is still in full bloom, so management efforts now with an herbicide are correctly timed. Applications of glyphosate are the best choice for Japanese knotweed management. For areas near and around water, you will need to use a glyphosate formulation that is labeled for these areas. Since knotweed commonly grows in wet areas or near streams, rivers or wetlands, the management of this invasive plant may invoke 310 CMR 10.00 (the Massachusetts Wetlands Protection Act). 310 CMR 10.00 regulates all activities in the resource areas identified in the Act. Before any management attempts are carried out, you should contact the Conservation Commission in the municipality to determine to what extent 310 CMR 10.00 might impact your project. For states other than Massachusetts, you should seek information about that state’s regulation for activities near water.

Common reed or phragmites, Phragmites australis, is in flower in New England, so now is the time for herbicide treatment. Glyphosate-based herbicide products are the best choice for the control of common reed. In areas near water, a formulation of glyphosate that is labeled for these areas should be used. Since common reed is most commonly associated with water and wet habitats, 310 CMR 10.00 (the Massachusetts Wetlands Protection Act) might be invoked. See comments in the Japanese knotweed section above for details about 310 CMR 10.00.

Reports of dodder in landscape beds continue to arrive via email. Dodder is a parasitic plant that lacks chlorophyll and is an annual vine with slender, yellow-orange stems that cover infected plants in a spreading, tangled, spaghetti-like mass. In mid- to late summer, dodder produces very small clusters of white, pink, or yellowish flowers that resemble the flowers of morning glory, as dodder is in the same plant family. At this point in the season, attempts should be made to remove the vines along with the flowers that will produce seeds. This may require cutting back of host plants.

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

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

Odds and Ends

Applications Open for MDAR Natural Disaster Recovery (NDR) Program for Agriculture

Growers significantly affected by the February deep freeze, May frosts, and/or July excessive rainfall and flooding can now apply for financial assistance through the Natural Disaster Recovery (NDR) Program for Agriculture. Applicants must be an agricultural operation as defined by M.G.L c.128, Section 1A... note that this definition includes "floricultural or horticultural commodities, and the growing and harvesting of forest products upon forest land".

Find the Request for Response (RFR) here:

Applicants may submit questions regarding this RFR and application process. Questions must be submitted by email to The deadline for questions is 4 PM on Friday, September 8, 2023. All questions and answers will be posted on the program website so that all applicants can review them.

An informational webinar was held for interested applicants at 9 am on Friday, September 8, 2023. To access the webinar, register here: Natural Disaster Recovery Program Information Session. This webinar will be recorded and made publicly available on the program website prior to the application deadline so that all potential applicants who are unable to attend the webinar live or who wish to further review the content may do so before submitting an application.

Applications must be submitted by 4:00 PM on Friday, September 29th, 2023. 

Additional Resources

Pesticide License Exams - The MA Dept. of Agricultural Resources (MDAR) is now holding exams online. For more information and how to register, go to:

To receive immediate notification when the next Landscape Message update is posted, join our e-mail list or follow us on Facebook.

For a complete listing of landscape, nursery, and urban forestry program upcoming events, see our calendar at

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

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

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

Diagnostic Services

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

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

Tick Testing - The UMass Center for Agriculture, Food, and the Environment provides a list of potential tick identification and testing options at:

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

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