Landscape Message: August 11, 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 August 25.  To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list 

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

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Scouting Information by Region

Environmental Data

The following data was collected on or about August 9, 2023. Total accumulated growing degree days (GDD) represent the heating units above a 50ºF baseline temperature collected via regional NEWA stations (http://newa.cornell.edu) for the 2023 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

MA Region/Location	2023 Growing Degree Days		Soil Temp (°F at 4" depth)		Precipitation (Gain in inches since last report)	Time/Date of Readings
	Gain since last report	2023 total	Sun	Shade
CAPE	299	1638	75	71	3.52	8/9/2023 12:00 PM
SOUTHEAST	306	1674	79	70	2.75	8/9/2023 2:45 PM
NORTH SHORE	305	1572	71	67	1.39	8/9/2023 9:30 AM
EAST	312	1795	76	70	3.41	8/9/2023 4:00 PM
METRO	283	1653	69	67	5.24	8/9/2023 5:45 AM
CENTRAL	286	1718	70	68	0.52	8/9/2023 3:45 PM
PIONEER VALLEY	284	1768	74	69	1.77	8/9/2023 12:00 PM
BERKSHIRES	240	1465	71	66	1.27	8/9/2023 6:15 AM
AVERAGE	289	1660	73	69	2.48	-
n/a = information not available

 

US Drought Monitor:  Drought conditions remain minimal; with the exception of the islands, which are currently classified as D0 (abnormally dry), there are no other drought areas currently designated in the state of Massachusetts.  State map as of Thursday 8/10: https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?MA

Phenology

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT NAME (Botanic / Common)	CAPE	S.E.	N.S.	EAST	METRO W.	CENT.	P.V.	BERK.
Clematis terniflora (sweet autumn clematis)	*	*	Begin	*	*	Begin	Begin	*
Polygonum cuspidatum / Reynoutria japonica / Fallopia japonica (Japanese knotweed)	Begin	Full/End	*	*	*	*	Begin	*
Clethra alnifolia (summersweet clethra)	Full	Full	Full	Full	Begin	Full	Full	Begin
Hibiscus syriacus (rose-of-Sharon)	Full	Full	Full	Full	Full	Full	Full	Begin/Full
Buddleia davidii (butterfly bush)	Full	Full	Full	Full	Full	Full	Full/End	Full
Campsis radicans (trumpet vine)	End	Full	Full	Full	Full	Full	Full	Full
Hydrangea paniculata (panicle hydrangea)	Full	Full	Full	Full	Full	Full	Full	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions:

The average temperature for the period from July 26 thru August 9 was 71°F with a high of 87°F on July 28 and a low of 52°F on August 2. The period began hot and muggy July 26 – July 30, giving way to much more comfortable conditions for the remainder of the period with lower dewpoints, daytime highs in the 70s, and nighttime lows in the 60s with a couple of nights dipping into the 50s. Overall a very pleasant period. Knock on wood, the weather station in Barnstable has yet to record 90°F or greater this summer.

Soil moisture during the period was dry/short with a small amount of rain recorded on July 29/30.  Unirrigated lawns were showing drought stress and beginning to brown. On August 8th, heavy downpours dropped more than 3.5 inches in Barnstable in about 1 hour; the downpour resulted in widespread road flooding and washouts, ending the period with adequate to excessive soil moisture. A tornado was confirmed in Marstons Mills from the same thunderstorm with some minor tree damage and power outages.   

Woody plants observed in bloom during the period include sourwood (Oxydendrum arboreum), mimosa (Albizia julibrissin), and hydrangeas. Herbaceous plants seen in bloom during the period include purple cone flower (Echinacea purpurea), shasta daisy (Leucanthemum x superbum), black eyed susan (Rudbeckia hirta), garden phlox (Phlox paniculata), and joe-pye weed (Eupatorium maculatum).

Pests/Problems:

  

 

 

 

 

 

 

 

 

 

 

Southern pine beetle (SPB) has been trapped for several years in MA and was recently confirmed causing mortality in a 13 acre stand of pitch pine on Nantucket. SPB is an important forest pest of pitch pine, one of the Cape’s dominant tree species; keep an eye out for this important pest. Also, keep on the lookout for spotted lanternfly (SLF). Spotted lanternfly is an introduced pest for which the primary host is tree of heaven but is capable of feeding on numerous other species. Box tree moth was confirmed on Cape Cod recently (also see Insect Section below for a link to a fact sheet with signs and symptoms). Box tree moth is an introduced pest that feeds on boxwood and can cause extensive damage. Check boxwoods for damage; see the above mentioned fact sheet for symptoms and signs to look for. Suspected invasive insect detections should be reported to the MA Introduced Pest Outreach Project.

Insects or insect damage observed during the period include Japanese beetle and Oriental beetle on herbaceous and woody plants, pine tip borer on pitch pine (heavy damage in some areas), turpentine beetle on pitch pine, white pine weevil damage to white pine, white pine aphid on Japanese white pine, leafminer and psyllid damage on boxwood, hibiscus sawfly on hardy hibiscus, rudbeckia psyllid on rudbeckia, sunflower moth caterpillar damage on purple coneflower, chilli thrips damage on bigleaf hydrangea (minor), eyespot gall on tuliptree, eyespot gall on red maple, and dogwood sawfly on alternate leaf dogwood. Two spotted spider-mite damage can be found on some herbaceous and woody plants. Eriophyid mite damage has also been observed on many woody species. 

Disease symptoms and signs observed during the period include: beech leaf disease (BLD) on American beech; foliar nematode on hosta and Japanese anemone; cercospora leaf spot on bigleaf hydrangea; hydrangea rust on smooth hydrangea (alternate host is hemlock); boxwood blight on boxwood; volutella blight on boxwood; basil downy mildew on basil; guignardia leaf blotch on horsechestnut; cedar apple rust, apple scab and fire blight on crabapple; maple anthracnose on red maple; oak anthracnose on white oak; pear trellis rust on callery pear; grey leaf spot on Japanese forest grass; and powdery mildew on many herbaceous and woody plants.

Now is a good time to confirm the presence of jumping worms in the landscape. Jumping worms reach maturity during the late summer at which time the white clitellum becomes distinct; the clitellum is 14-16 segments from the head. For more details, see these UMass Extension fact sheets.

Other damage observed during the period includes snail and slug damage to hosta, rabbit damage on numerous herbaceous plants, and deer browse on hosta.

Weeds in bloom include spotted spurge (Euphorbia maculata), purslane (Portulaca oleracea), sheep’s bit (Jasione montana), common tansy (Tanectum vulgare), redroot pigweed (Amaranthus retroflexus), lambsquarters (Chenopodium album), Pennsylvania smartweed (Polygonum pensylvanicum), and knapweed (Centaurea maculosa).

Southeast Region (Dighton)

General Conditions:

"Summertime and the livin' is easy." The short-day wildflowers are plentiful along roadsides and the honeyed scent of Clethra summersweet delights the nose as you pass along wetland hollows. After a brief glimpse of cool autumn days, we're back to summer heat, humidity, passing thunderstorms, downpours, and flash flooding. The high temperature was 85°F on Thursday the 27th of July. Both Wednesday, August 2, and the following Thursday had morning lows of 53°F sending us scrambling to find our sweaters. There was light rain on Sunday, July 30 but the bulk of our precipitation came in a deluge on Tuesday, August 8th, for a total of 2.75 inches. The average temperature was 72°F. The highest wind speed was 24 mph on Thursday, July 27th.

Plants in flower: Buddleia davidii (butterflybush), Campsis radicans (trumpet vine), Clethra alnifolia (coastal sweet pepperbush or summersweet), Hibiscus syriacus (rose of Sharon), Hydrangea paniculata (panicled hydrangea), Lythrum salicaria (purple loosestrife), Oxydendrum arboreum (sourwood), Reynoutria japonica (Japanese knotweed).

Pests/Problems

Tussock moth on common milkweed. Baldfaced wasps and yellow jacket nests are getting large and aggressive. Despite a bone-chilling 7° degree low over the past winter, bagworms are still wreaking havoc in evergreens on the south coast. Unfortunately, most homeowners are unfamiliar with bagworms. Many mistake the browning and defoliation for drought until their plants are mostly consumed. Yellow nutsedge is obvious but not yet flowering on lawns. 

North Shore (Beverly)

General Conditions:

The first few days of this reporting period were very hot and humid with day temperatures in the mid to high 80s and night temperatures in mid 70s. However things changed and the rest of the period was very pleasant with day temperatures in the low to high 70s and night temperatures in the low 50s to mid 60s with low humidity. The average daily temperature was 70℉. The average daily maximum temperature was 79°F and the daily minimum temperature was 61℉. The maximum temperature of 89℉ was recorded on July 27 and the minimum temperature of 51℉ was recorded on August 2, and approximately 1.39  inches of rain were recorded at Long Hill. Most of the rain (1.28 inches) fell on August 8. Woody plants seen in bloom include: bottlebrush buckeye (Aesculus parviflora), the bee-bee tree or Korean evodia (Tetradium daniellii), sourwood (Oxydendrum arboreum), panicle hydrangea (Hydrangea paniculata), summersweet clethra (Clethra alnifolia), cutleaf chastetree (Vitex negundo), butterfly bush (Buddleia davidii), Chinese scholar tree (Styphnolobium japonicum), rose-of-Sharon (Hibiscus syriacus), and Castor-aralia (Kalopanax pictus). A common pawpaw tree (Asimina triloba) was observed in fruit. Some of the herbaceous plants seen in bloom include: milkweed (Asclepias spp.), globe thistle (Echinops ritro), garden phlox (Phlox paniculata), purple coneflower (Echinacea purpurea), black-eyed Susan (Rudbeckia spp.), hostas (Hosta spp.), cranesbill (Geranium spp.), fairy candles (Actaea racemosa), yarrow (Achillea millefolium), yellow corydalis (Corydalis lutea), Joe Pye weed (Eutrochium dubium), Japanese anemone (Anemone x hybrida), fleece flower (Fallopia aubertii), summer flowering roses (Rosa spp.), clematis vines (Clematis paniculata), and an assortment of annuals.

Pests/Problems:

Powdery mildew continues to be observed on monarda, garden phlox and susceptible lilacs. Some of the very susceptible crabapple tree varieties are dropping leaves due to apple scab disease damage on the leaves. Possible leaf blotch was observed on peony. Provide good air circulation and avoid wetting the leaves. Weeds are thriving due to moist soil and warm temperatures. Oriental bittersweet (Celastrus orbiculatus) is growing vigorously. Oriental bittersweet seedlings are easy to remove when the soil is moist and the population is small. Pull steadily and slowly to minimize soil disturbance. Remember that ticks and mosquitoes are still very active. Protect yourself with insect repellent when working outdoors, especially at dawn and dusk.

East (Boston)

General Conditions:

The last week of July was hot and humid. On July 29th we experienced unsettled weather with thunderstorm and tornado warnings. We received 2.2 inches of precipitation, a drastic reduction in temperatures, and several consecutive days with zero humidity. July ended with a total of 8.38 inches of precipitation. The first week of August, daytime temperatures averaged 79℉ with overnight lows averaging 61℉. We had another severe weather warning on August 8th accompanied by 1.03 inches of precipitation. The landscape is lush; trees and shrubs continue to put on new growth. The pollinator magnet, commonly called the bee-bee tree, Tetradium daniellii (Korean evodia) is in full bloom.

Pests/Problems:

Powdery mildew is prevalent on lilac (Syringa spp.), bee balm (Monarda spp.) and garden phlox (Phlox spp.). Unmanaged pokeweed (Phytolacca americana) along roadsides is five feet tall and forming fruit.

Metro West (Acton)

General Conditions:

We are in the full swing of summer, experiencing some hot and muggy days, yet no heat waves as of yet. I’m not complaining. The rain pattern continues with some sort of precipitation reported on all but 5 of the 14 days in this reporting period. The historical monthly average rainfall for the month of July is 3.43” and a grand total of 6.17” of rain was recorded for the month. The average rainfall for the month of August is 3.72” and as of the 8th, the total rainfall recorded for the month has been 4.42”.  One rain event on the 8th provided much of that rain. This is the second month in a row where precipitation exceeded its historical monthly average. 

Pests/Problems:

Observed in the landscape was sawfly caterpillar feeding on Betula nigra (river birch) foliage. The rain event on the 8th with 4.4” of rain recorded caused much flooding and erosion in this area.

Central Region (Boylston)

General Conditions:

During this reporting period in central Massachusetts, the weather has been trending toward cooler temperatures and less overall precipitation. Average ambient temperatures have fluctuated from low 60s to high 70s. Peak temperatures were observed on 8/5 and 8/6 at 82.8℉ and 83.5℉ respectively. The lowest temperature was observed on 8/2 at 49.5℉, which isn’t cold enough to cause plant damage, but alludes to a cooling trend. Total precipitation was low at 0.52”. A rain event occurred on 8/8, during which 0.48” of precipitation fell. Relative humidity levels have decreased and it’s been a nice reprieve from the stifling mugginess of July. Otherwise, weather conditions were similar to the last reporting period. With days becoming shorter and overall temperatures falling, we are gradually moving into autumn. 

Of note, Physostegia virginiana (obedient plant), Symphyotrichum novi-belgii (New York aster), and Solidago spp. (goldenrod) have recently come into bloom. Rudbeckia hirta (black-eyed Susan) and Daucus carota (Queen Anne’s lace) have held onto their blooms. We’re excited to see the fall display of blooms. 

Pests/Problems:

No significant pests or pathogens to report. 

Pioneer Valley (Amherst)

General Conditions:

There was finally some relief from the heat and humidity during this past reporting period after a cold front and strong thunderstorms swept through the region on 7/29. The cooler, Canadian air mass resulted in a record-low temperature of 48°F on the morning of 8/2, recorded at Westover AFB in Chicopee. During the first week of August, high temperatures have moderated between the upper 70s to mid-80s with cool, and sometimes muggy, nighttime conditions. Rainfall across the tri-counties ranged from 1–5″ over this reporting period. Hampden County received the highest totals, with numerous weather stations around Springfield recording in excess of 3″. As a result, soil moisture remains very good and we’re entering a prime period for late summer and autumn transplanting. The long-term forecast calls for more scattered showers and thunderstorms, but with far more comfortable temperatures. The Northeast Regional Climate Center offers a great summary of the record wet and heat the northeast experienced during the month of July. As we enter late summer, there’s still an abundance of color in the landscape, with lily, coneflower, hibiscus, butterfly weed, swamp milkweed, Joe Pye weed, ironweed, and black-eyed Susan in bloom. The persistent rainfall has kept many lawns green and crab grass is growing at a strong rate (and currently going to seed). Many fall-germinating weeds have a plentiful seed crop from the wet summer. 

Pests/Problems:

Many trees and shrubs are looking robust due to the abundance of rainfall this growing season. The deep watering is especially beneficial for mature trees that suffered drought stress during the summer of 2022. Typically at this time of year, many plants can appear disheveled as the rigors of the summer manifest, but this year those numbers are fewer. Wood-decaying fungal pathogens that cause root and butt rot of trees continue to be very conspicuous at this time. Across the UMass campus, mushrooms and conks of the following pathogens were recently observed: Laetiporus cincinnatus (chicken of the wood) on Norway maple, Phaeolus schweinitzii (velvet top fungus) on European larch, Ganoderma sessile (reishi) on red and sugar maple, Bondarzewia berkeleyi (Berkeley’s polypore) on English oak, and Niveoporofomes spraguei (green cheese polypore) on black oak. Significant feeding damage on birch caused by Japanese beetles has been locally abundant. Damage from the jumping oak gall wasp is significant on some trees, further exacerbated by Tubakia leaf blotch. Symptoms of Tubakia leaf blotch tend to develop in late summer, and appear as large, circular spots and irregular blotches. A significant number of apples and crabapples are dramatically thinning out due to apple scab and could be mostly defoliated by the end of the month. While this can be alarming, many trees seem to withstand this early loss of foliage without any major impact on health the following growing season. Scattered serviceberries are also thin, having prematurely shed most of their interior canopy foliage. Rust fungi have had a good season and leaf spots/blotches and fruit rot is common on members of the Rosaceae. Mosquito populations are still very high along with various wasps, hornets and bees.

Berkshire Region (West Stockbridge)

General Conditions:

Except for July 28 when high temperatures reached 88^oF in North Adams, 86^o in Richmond, and 85^o in Pittsfield, temperatures over the past two weeks have been quite pleasant. Daytime highs have been most often been in the mid-70s and night time temperatures in the 50s or mid to upper 40s in those three NEWA locations where weather data is gathered. Interestingly, some rainfall fell on 7 of the days from July 26 through August 8 although the amounts were quite small on many of those days. The highest total rainfall for that span was in North Adams where 2.46 inches of rain were recorded. Pittsfield rainfall amounted to 1.68 inches while Richmond totaled 1.47 inches, and at this site in West Stockbridge rainfall amounted to only 1.27 inches. For the year, total rainfall is about 5 ½ inches above normal, as recorded at the Pittsfield airport. Soils at this time are moist. With the moist soils and moderate temperatures, growth of turfgrass has been rapid. Also, un-mowed meadows or those that are maintained with only an early spring mowing are aglow with wildflowers in bloom.

Pests/Problems:

With persistent rainfall, the mosquito population remains high and is quite the nuisance for outdoor laborers. Reports of tick bites also remain high and caution and following the recommended precautions for avoiding the ticks is highly advisable. The moist conditions have favored a high slug and snail population, and ultimately much damage to the foliage of herbaceous plants. As would be expected with frequent showers, powdery mildew and various leaf spot diseases are prominent and the most common of diseases observed in the landscape. Severe defoliation of some crabapples due to apple scab is often seen. Roses are also suffering a bit of defoliation from black spot disease. Daylilies appear to be infected with daylily leaf streak, caused by the fungus Aureobasidium microstictum. Another negative outcome from the torrential rains that have occurred at various times this year is the leaching of plant nutrients (primarily nitrogen) from the soil. Chlorotic or yellowing of foliage has appeared, especially on herbaceous plants. Among the pest problems seen are magnolia scale and magnolia leafminer (possibly the  magnolia serpentine leafmining caterpillar, Phyllocnistis magnoliella). Finally, perhaps due to the lushness of vegetation this year, browsing by deer and rabbits is a big problem in many landscapes.

Regional Scouting Credits

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

Woody Ornamentals

Diseases

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

Leaf spots, blotches and premature shedding in the canopy of various birch species and cultivars (Betula sp.) due to birch anthracnose. Two fungal pathogens, Ophiognomonia (pictured) and Marssonina, are primarily responsible for birch anthracnose in the region. Starting mid-summer, leaves become yellow to brown and are prematurely shed from the canopy. Closer inspection reveals various circular spots, irregular blotches, and a marginal blight that is typical of anthracnose infections on deciduous hardwoods. These necrotic patches are often gray to brown in color. During wet summers, birch anthracnose can be a problem and significant volumes of foliage can be shed. Management of diseased trees should focus on minimizing other stresses to ensure vigor is restored in subsequent years. Birch is a shallow-rooted tree and should be surrounded by a large mulched area free of turfgrass to avoid competition for soil moisture during drier periods.

Phomopsis twig and branch cankering on eastern hemlock (Tsuga canadensis). The tree is roughly 40-years-old and resides in a mulched bed along a driveway. The managing arborist noted significant needle yellowing and shedding within the interior canopy. Phomopsis is very common on hemlocks weakened by drought stress and winter injury, primarily attacking current season’s twigs. It is one of the few fungal pathogens that can be regularly encountered on this host. This tree was likely predisposed by droughts in 2020 and 2022.

Verticillium wilt of Japanese maple (Acer palmatum) caused by Verticillium dahliae. Mature tree, approximately 50-years-old, growing in full sun within a shallow depression in a managed landscape. Soils are composed of sandy-loam and are considered droughty and no supplemental water is provided. Over the past several years, canopy thinning and branch tip dieback has been observed. At present, ~60% of the foliage is showing symptoms of water starvation and dieback. Many Japanese maples are likely challenged by Verticillium but are able to resist the disease. When drought-stressed, however, host defenses are readily overcome by this native vascular wilt pathogen.

Infestation of the pear psylla (Cacopsylla pyri) on an unknown cultivar of common pear (Pyrus communis). The espalier tree is roughly 12-years-old and has been present at the site for six years. It resides in a vegetable garden, anchored to a brick house, with drip irrigation in loam soils. Direct sun is not abundant in the current setting. This summer, premature leaf shedding, browning foliage and excessive sooty mold was observed in the canopy. Nymphs of the pear psylla were present on the submitted foliage and no foliar pathogens were detected. This naturalized pest, introduced in the early 1800s, produces large volumes of honeydew and infested trees quickly become coated in sooty mold fungi. Pear psylla infestations lead to premature leaf drop, poor fruit production, and undersized fruit.

Lower branch dieback of Norway spruce (Picea abies ′Cupressina′) due to transplant shock and twig cankering by Setomelanomma holmii. The tree is less than 10-years-old and was transplanted one year ago. The site is characterized by full sun, well-drained soils composed of sand and loam and drip irrigation. In the lower half of the canopy, interior twig and branch browning developed. The needles were pale green to brown in color and appeared water-starved. There was no evidence of any needle cast pathogens after incubation and microscopic analysis. However, Setomelanomma was detected, sporulating on the twigs at the base of the needles. The shock of transplant likely predisposed the tree, allowing the fungus to cause disease and dieback of interior canopy parts.

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

Insects and Other Arthropods

Citizen Science Opportunity: Reporting Native Ground Nesting Bees

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

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

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

Current Nuisance Problems of Note:

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

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

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

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

• 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.

Additionally, WNV positive mosquito samples have been collected in Berkshire, Hampden, Worcester, Norfolk, Middlesex, Essex, Suffolk, and Plymouth counties, but there have been no reported human cases to date.

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

Click here for more information about mosquito repellents.

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

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

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

Highlighted Invasive Insects & Other Organisms Update:

• 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 https://massnrc.org/pests/report.aspx

• 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: nicole.keleher@mass.gov. More information about southern pine beetle is also available from MA DCR at https://storymaps.arcgis.com/stories/b60f63199fa14805a8b9f7c82447a25b .

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 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.

• Emerald Ash Borer: (Agrilus planipennis, EAB) has been detected in at least 11 out of the 14 counties in Massachusetts. A map of these locations across the state may be found at https://ag.umass.edu/fact-sheets/emerald-ash-borer . Additional information about this insect is provided by the MA Department of Conservation and Recreation at https://storymaps.arcgis.com/stories/b60f63199fa14805a8b9f7c82447a25b.

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

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

For More Information, see these UMass Extension Fact Sheets:

Earthworms in Massachusetts – History, Concerns, and Benefits

Jumping/Crazy/Snake Worms – Amynthas spp.

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

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

Tree & Shrub Insect Pests (Native and Invasive):

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

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

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

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

• Asiatic Garden Beetle: Maladera castanea adults are active and are typically most abundant in July and August. These rusty-red colored beetles are bullet-shaped and active at night. They are often attracted to porch lights. This beetle feeds on a number of ornamental plants, defoliating leaves by giving the edges a ragged appearance and also feeding on blossoms. Butterfly bush, rose, dahlia, aster, and chrysanthemum can be favored hosts.

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

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

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

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

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

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

 

 

 

 

 

• Dogwood Sawfly: Macremphytus tarsatus has one generation per year. The larvae of the dogwood sawfly overwinter in decaying wood and occasionally compromised structural timber. An overwintering "cell" is created in this soft wood. Pupation occurs in the springtime and adults can take a lengthy time to emerge, roughly between late May and July. 100+ eggs are laid in groups on the underside of leaves. Eggs hatch and the larvae feed gregariously, initially skeletonizing leaves. As the caterpillars grow in size, they are capable of eating the entire leaf with the exception of the midvein. Larval appearance varies greatly throughout instars, so much so that one might mistake them for multiple species. Early instars are translucent and yellow, but as the caterpillars grow they develop black spots (over yellow) and become covered in a white powder-like material. Larvae and their shed skins may resemble bird droppings. Full grown larvae begin to wander in search of a suitable overwintering location. Rotting wood lying on the ground is preferred for this.

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

• Fall 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.

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

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

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

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

• 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.

• Two-Spotted Spider Mite: Tetranychus urticae is a “warm-season” mite that loves hot and dry weather, which may favor the quick reproduction and build-up of this pest. Management should seek to preserve beneficial predatory mites. Monitor susceptible hosts (elm, maple, redbud, ash, black locust, tuliptree, and many deciduous shrubs) for increasing numbers of these mites until mid-August. Mites will be found on the undersides of leaves and cause stippling of the foliage.
• Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. By 2008, viburnum leaf beetle was considered to be present throughout all of Massachusetts. Larvae are present and feeding on plants from approximately late April to early May until they pupate sometime in June. Much damage from viburnum leaf beetle feeding is currently apparent in areas of Massachusetts where this insect has become established. See photo courtesy of Tom Ingersoll from 6/5/2023. Adult beetles emerge from pupation by approximately mid-July and will also feed on host plant leaves, mate, and lay eggs at the ends of host plant twigs where they will overwinter. This beetle feeds exclusively on many different species of viburnum, which includes, but is not limited to, susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum, and V. rafinesquianum. Some viburnum have been observed to have varying levels of resistance to this insect, including but not limited to V. bodnantense, V. carlesii, V. davidii, V. plicatum, V. rhytidophyllum, V. setigerum, and V. sieboldii. More information about viburnum leaf beetle may be found at http://www.hort.cornell.edu/vlb/ and at https://ag.umass.edu/landscape/fact-sheets/viburnum-leaf-beetle.

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

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

Landscape Weeds

For identification of weed species noted below, refer to UMass Extension's Weed Herbarium.

Summer annual weeds in landscape beds continue to get larger as a result of the warm and rainy weather pattern. A non-selective herbicide will result in unsightly dead vegetation, so hand weeding may be needed. Physical removal by hand weeding might require a fresh mulch layer since the existing mulch barrier may be compromised. A fresh layer of mulch will cover any plants you could not remove as well as provide protection against the germination of winter annual weeds later in the season.

Several reports of dodder in landscape beds. Dodder is a parasitic plant that lacks chlorophyll. It is an annual vine with slender, yellow-orange stems that cover infested 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 herbaceous ornamental perennials. Next season, a landscape mulch should be applied in the spring; this will reduce the success rate of dodder establishing from seed. A preemergence herbicide labeled for landscape use can be applied to the fresh mulch after it settles. Monitor the area closely and physically remove young dodder vines before they attach to 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 (Scythe^TM, Reward^TM) or the non-chemical/organic herbicide products 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 continue to cause contact dermatitis. Urushiol occurs in all parts of the plant, including the roots.

As Japanese knotweed has entered its flowering period, we are officially in knotweed management season. Applications of glyphosate are the choice for knotweed. 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 where you are working 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 regulations for activities near water.

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

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Additional Resources

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

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Diagnostic Services

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

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

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

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

• The Massachusetts Nursery and Landscape Association Fund
• The Massachusetts Department of Conservation and Recreation, Award #ISADCR28219926UMA23A
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