Landscape Message: April 30, 2021

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

The Landscape Message will be updated weekly in May. The next message will be posted on May 7. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list 

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Scouting Information by Region

Environmental Data

The following data was collected on or about April 28, 2021. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via regional NEWA stations for the 2021 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

MA Region/Location	GDD		Soil Temp (°F at 4" depth)		Precipitation (1-Week Gain)	Time/Date of Readings
	1-Week Gain	2021 Total	Sun	Shade
CAPE	14.5	45.5	51	47	0.80	12:00 PM 4/28
SOUTHEAST	15.5	62.5	67	52	0.64	3:00 PM 4/28
NORTH SHORE	20.5	76.5	53	47	0.61	4:00 PM 4/28
EAST	19	88	62	53	0.56	5:00 PM 4/28
METRO	17	81.5	51	48	0.19	5:45 AM 4/28
CENTRAL	17.5	88.5	56	56	0.45	3:00 PM 4/28
PIONEER VALLEY	14.5	93.5	55	49	0.64	12:00 PM 4/28
BERKSHIRES	11	60	52	45	0.54	8:15 AM 4/28
AVERAGE	16	75	56	50	0.55	_
n/a = information not available

See MA drought status as of April 27 here: 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.
Cornus florida (flowering dogwood)	*	Begin	Begin	*	*	*	Begin/Full	*
Rhododendron spp. (early azaleas)	Begin	Begin	Begin/Full	*	*	Begin	Begin/Full	Begin/Full
Malus spp. (crabapple)	*	Begin	*	Begin	*	*	Full	Full
Cercis canadensis (redbud)	*	Begin	Full	Begin/Full	Full	Begin	Full	*
Amelanchier spp. (shadbush, serviceberry)	Begin	Full/End	Full	Full	Full	Full	Full/End	Full
Pyrus calleryana (Callery pear)	Full	Full/End	Full/End	Full/End	Full/End	Full/End	Full/End	Full
Magnolia soulangiana (saucer Magnolia)	Full/End	End	Full/End	Full/End	Full	Full/End	Full/End	Full
Prunus serrulata (Japanese flowering cherry)	*	Full	Full	Full/End	Full/End	End	Full/End	Full
Rhododendron 'P. J. M.'	Begin/Full	Full	Full	Full	Full	Full	Full	Full
Forsythia x intermedia (border Forsythia)	Full/End	End	End	End	End	End	Full/End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The period from April 21-27 was mostly sunny with an average temperature of 49˚F. The high was 69˚F on April 24 and a low of 32˚F was on April 22 with frost in low lying areas. The primary precipitation event of the period was on April 25, resulting in ~0.6 inches of rain. There was less than 0.1 inches on April 21 and slightly more than 0.1 inches on April 28. Plants seen in bloom include hellebores, Pulmonaria, hyacinths, grape hyacinths, daffodils, tulips, creeping Phlox, European wild ginger, fringed bleeding heart, yellow alyssum, Epimedium, ‘Ogon’ spirea, flowering quince, Andromeda, and Pachysandra. ‘PJM’ Rhododendron is in full bloom in my yard which often coincides with the arrival of hummingbirds.

Pests/Problems: Winter moth has hatched and can be found in the buds of host species. Oak buds are still a little tight for winter moth. The caterpillars are very tiny (4mm) and can be found feeding in many species with expanding buds, especially maple (see photo). Damage and caterpillars are difficult to see at this time without magnification. Winter moth populations are not expected to cause defoliation, but holes are likely to be seen in the leaves of host plants. Apples and blueberries grown for production are likely to require some winter moth management. Fall cankerworm has caused some small patches of defoliation the last couple of years, so keep on the lookout for these areas in the next couple of weeks. As caterpillars, winter moth and fall cankerworm can be differentiated by the number of prolegs; winter moth having two and fall cankerworm having two and half.

Lecanium scale is still present in high numbers in some locations and in other locations appear to be under control via entomopathogenic fungi. Scout for lecanium scale (see photos) to determine whether treatment is necessary; the time to target this insect with dormant oil is now. Signs of recent activity by the black oak gall wasp (Zapatella davisae) was seen in a black oak with a history of black oak gall wasp damage (see photo). Hemlock woolly adelgid egg masses are easily seen at this time. The significance of lichen growth on trees, oaks and other ornamentals, is a common question at this time of year. In many cases, excessive lichen growth occurs on trees with thinning canopies. Thinning canopies are often a result of chronic stresses. For a large portion of oaks, the chronic stresses of winter moth, gypsy moth, black oak gall wasp, and multiple droughts have predisposed them to boring beetles and decay fungi. Beetles and fungi have led to the widespread decline and death of oaks which are now ideal locations for lichens to grow. With other ornamental trees and shrubs, excessive lichen growth is an indicator of poor vigor and poor growth, and should be investigated for causes of chronic stress. Dieback as a result of last season’s drought is widespread on Rhododendrons in unirrigated landscapes. Drought damaged plants seen this week also include inkberry, Ilex glabra. Above ground and below ground, symptoms look similar to those of root rot. The previous drought is likely to result in attacks by secondary pests such as bark beetles, borers and fungi on weakened plants.

The invasive plant fig buttercup is in full bloom. Other weeds seen in bloom include hairy bittercress, whitlow grass, arabidopsis, chickweed, speedwell, common violets and some dandelions. Lawns continue to green-up; however, our horticulture clinic has been handling a lot of inquiries about damaged, weedy and/or mossy lawns. Forsythia is in full bloom so now is the time to apply pre-emergent herbicides for crabgrass control. Rabbits are active. Don’t forget to protect yourself from deer ticks.

Southeast Region (Dighton)

General Conditions: We're on the cusp of T-shirt and shorts weather and some of the hardier folk have already transitioned. Often, what seemed appropriate clothing in the early morning can be stultifying before noon. Be sure to bring sun screen and insect repellent to work with you or prepare to pay the painful price. Plant growth is developing at a steady pace, with something new to discover daily. Others, ephemeral, pass by all too quickly. "Parting is such sweet sorrow." Among the plants now flowering I have noticed: Acer saccharum (sugar maple), A. platanoides (Norway maple), Amelanchier canadensis, (serviceberry, shadblow), Anemone nemerosa (wild anemone), Alliaria petiafolia (garlic mustard), Aurinia saxatilis (basket of gold), Betula populifolia (grey birch) Cercis canadensis (redbud), Cornus florida (dogwood), Chaenomeles spp. (flowering quince), Elaeagnus umbellata (autumn olive), Euphorbia spp. (yellow spurge), Forsythia x intermedia (border Forsythia), Glechoma hederacea (creeping Charlie), Iberis sempervirens (candytuft), Lamium amplexicaule (henbit deadnettle), Lamprocapnos spectabilis (bleeding heart), Leucojum aestivum (giant snowdrop), Lunaria annua (honesty, money plant), Malus spp. (crabapple), Narcissus (daffodil), Phlox subulata (creeping Phlox), Poa annua (annual bluegrass), Magnolia soulangeana (saucer Magnolia), M. stellata (star Magnolia), Muscari spp.(grape Hyacinth), Pieris japonica (Japanese Andromeda), Prunus cerasifera (purple-leaf plum), P. x cistana (purple-leaved sand cherry), P. persica (peach), P. serrulata (‘Kwanzan’ cherry), P. subhirtella (Edo higan cherry), P. virginiana (chokecherry), Pyrus communis (common pear), P. calleryana (Callery pear), Quercus rubra (northern red oak), Q. palustris (pin oak), Rhododendron "P.J.M.", R. maculatum (Korean azalea), Rumex acetosella (red sorrel), Spiraea prunifolia (bridalwreath spirea), Stellaria media (chickweed), Taraxacum spp. (dandelion), Tulipa spp.(tulip), Trillium erectum (wake robin, red Trillium), T. grandiflorum (white Trillium), Viburnum carlesii (Korean spice Viburnum), Viola blanda (common violet) V. tricolour (Johnny-jump-up, wild violet), and Vinca minor (periwinkle).

Pests/Problems: Ticks are ubiquitous. If you've been outdoors at all take a moment and check yourself. Pets are at particular risk. Portions of western MA are already officially suffering drought conditions. If the current pattern continues, we will be joining them before summer. Prudence dictates that any installations or new plantings should have provisions for supplemental irrigation that does not rely on public water supplies. Native plants adapted to our sandy soils and xerophiles are good choices.

North Shore (Beverly)

General Conditions: We had beautiful spring weather during this reporting period with mostly sunny days and comfortable temperatures. The average daily temperature was 50˚F with the highest temperature of 72˚F recorded on April 24 and the lowest temperature of 32˚F recorded on April 22. Approximately 0.61 inches of rain were recorded at Long Hill. Most of the precipitation was recorded on April 22 (0.30 inches) and April 28 (0.25 inches). Soils are moist and suitable for planting. Turf has greened up and several plants are in bloom and providing color in the landscape. Woody plants observed in bloom include: serviceberry (Amelanchier arborea), weeping higan cherry (Prunus subhirtella), Japanese Pieris (Pieris japonica), Forsythia spp., mountain Pieris (Pieris floribunda), Kwanzan cherry (Prunus serrulata), star Magnolia (Magnolia stellata), Korean Rhododendron (Rhododendron mucronulatum), Callery pear (Pyrus calleryana) Burkwood Viburnum (Viburnum x burkwoodii) and Allegheny serviceberry (Amelanchier laevis). Spring flowering herbaceous plants seen in full bloom include: bleeding heart (Dicentra spectabilis), Japanese rose (Kerria japonica), daffodils (Narcissus spp.), bloodroot (Sanguinaria canadensis), Allegheny Pachysandra(Pachysandra procumbens), Vinca vine (Vinca minor) and tulips (Tulipa spp.). 

Pests/Problems: Deer browsing was noted on some plants. Invasive yellow/fig buttercup weed, also known as lesser celandine (Ficaria verna) is in full bloom, as are dandelion (Taraxicum officinale) and common blue violet (Viola papilionacea or V. sororia). Invasive Norway maples (Acer platanoides) are in full bloom with yellowish-green flowers all over the landscape. Ticks are active and people should be careful to protect themselves when working outdoors.

East Region (Boston)

General Conditions: April has continued in typical April fashion. We have had several days with high temperatures in the 60’s and a high of 71˚F on the 24th. We experienced light overnight frosts on April 22 and 23. Precipitation has remained at a minimum. Turf is greening up and the landscape is an abundance of color. Daffodils and tulips continue to flower. Cherry (Prunus spp.), redbud (Cercis canadensis) and serviceberry (Amelanchier spp.) continue to flower.

Pests/Problems: Lack of precipitation is an ongoing issue. We received a paltry 0.56 inches of precipitation over the past seven days. Soils are dry and new plantings require supplemental watering. Garlic mustard (Alliaria petiolata) is flowering. The invasive Norway maple (Acer platanoides) flowers can be seen everywhere - along roadsides, in woodlands, as street trees and ornamentals. Knotweed (Fallopian japonica) is 1-2 feet tall in some areas. Ficaria verna (fig buttercup, lesser celandine) is invading moist planting beds and lawns.

Metro West (Acton)

General Conditions: Happy Arbor Day! It sure feels like a typical spring with the mix of warm, cool, windy, and rainy weather. A high temperature of 73°F was recorded on the 24^th and a low of 30°F was recorded on the 22^nd. Precipitation has been recorded for this area on two of the past seven days, bringing our total rainfall for this month to 2.02”, falling far short of the April monthly average of 4.16”. It is raining outside as I write so there will be more much needed precipitation before month’s end. The landscape is filled with color and observed in some stage of bloom this past week were the following woody plants: Amelanchier spp. (shadbush, serviceberry), Cercis canadensis (redbud), C. canadensis ‘Alba’ (white flowering redbud), Chaenomeles speciosa (common flowering quince), Forsythia spp., Lindera benzoin (common spicebush), Magnolia x loebneri 'Merrill', (Merrill Magnolia), M. x soulangeana (saucer Magnolia), Pieris japonica (Japanese Pieris), Prunus spp. (cherry), Pyrus spp. (pear), Rhododendron 'P. J. M.' (PJM Rhododendron), Spirea thunbergii (Thunberg spirea), Vaccinium angustifolium (lowbush blueberry), V. corymbosum (highbush blueberry), and Viburnum x burkwoodii (Burkwood Viburnum). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Anemone pulsatilla (pasque flower), A. nemorosa (wood anemone), Asarum europaeum (European ginger), Aurinia saxatilis (basket of gold), Brunnera macrophylla (alkanet), Caltha palustris (marsh marigold), Chionodoxa luciliae (glory of the snow), Dicentra canadensis (squirrel corn), D. cucullaria (dutchman's breeches), D. eximia (fringed bleeding heart), D. spectabilis (old fashioned bleeding heart), D. spectabilis ‘Alba’ (white flowering old fashioned bleeding heart), Epimedium versicolor 'Sulphureum' (yellow flowering barrenwort), Erythronium americanum (yellow trout-lily), Helleborus niger (Christmas rose), Hepatica spp. (liver leaf), Hyacinthus spp. (Hyacinth), Mertensia virginica (Virginia bluebells), Muscari spp. (grape Hyacinth), Narcissus spp. (daffodil), Omphalodes verna (blue-eyed Mary), Pachysandra procumbens (Allegheny spurge), P. terminalis (Japanese Pachysandra), Primula spp. (primrose), Pulmonaria longifolia (lungwort), P. rubra (salmon colored lungwort), Puschkinia libanotica (striped squill), Sanguinaria canadensis (bloodroot), S. canadensis 'Multiplex' (double bloodroot), Trillium erectum (red flowering Trillium), T. sessile (toadshade), Tulipa spp. (tulip), Vinca minor (periwinkle), Viola spp. (violet), and Waldsteinia fragaroides (barren strawberry).

Pests/Problems: Precipitation totals for this area are below monthly averages so the moderate drought designation continues for this area. Some of the potential impacts of this drought might include stressed trees, shrubs and perennials, water sources below capacity, the decline in honey production, and the increase in wildfires. Acer platanoides (Norway maple) is in full bloom. This invasive tree is hard to miss now that it is in bloom and its flowers are a bright yellowish-green and are easily seen on trees found growing most everywhere. Continuing to flourish everywhere in the landscape is Alliaria petiolata (garlic mustard). It is just beginning to flower so pull out as much as you can as soon as possible before seeds form, which happens quickly.

Central Region (Boylston)

General Conditions: Average rainfall for the month of April is typically over four inches. In Boylston, we’ve received about two inches for the month that ends on Friday, or about half the average precipitation for this month. The story of the season thus far appears to be the beginning stages of drought. The US Drought Monitor data (current as of April 20) shows most of the state either abnormally dry or under moderate drought. This is not a great sign for this time of year. Soils remain moist, owing in part to cooler temperatures, but without substantial rainfall in May and June, we will see continued drought stress in plants across the landscape this summer. Thankfully, the lack of rainfall has not had an impact on spring bloom across the region. Many early native plant species are in bloom, including Trillium, Hepatica, violets, barren strawberry, and trout lily. There is certainly an abundance of color in the garden, with daffodils, tulips, Hyacinths, Fritillaria, and other spring bulbs in full, colorful display.

Pests/Problems: Dandelions and creeping Charlie are very active in lawn areas.  

Pioneer Valley Region (Amherst)

General Conditions: April has come to a close in the Pioneer Valley as the spring season marches onward. We had another week of widely fluctuating temperatures and conditions. On the morning of 4/22, temperatures bottomed out between 30–32°F across the lower elevations, generating concern about frost injury on tender new growth and flowers. While high temperatures crawled into the 40s, snow flurries and wind gusts approaching 40 mph (recorded at Barnes Airport, Westfield) made it feel like early March. Then, only two days later on 4/24, high temperatures peaked at >70°F with bright sun and calm winds. So, we continue to bounce from cold and cloudy to mild and sunny. Strong afternoon winds continue to be a regular feature as well. The long-term forecast calls for much warmer nights (>50°F), which will really accelerate new plant growth. The region experienced scattered rain showers on 4/21, 4/25 and 4/28, with more rain expected on 4/29 and 4/30. A ferocious band of thunderstorms swept through southern New England during the early morning hours of 4/28, with some particularly booming and rolling thunder. But, accumulations from the most recent storms have been minimal and with the low humidity and persistent winds, upper soil surfaces are drying out once again in full sun landscapes. The U.S. Drought Monitor categorizes the entire tri-county region in drought conditions with the majority in D0 (abnormally dry). The big soak on 4/15–16 certainly helped improve soil moisture but after a dry early spring season we need another big rain event. The spring array of color continues to dazzle with new additions appearing every week. Crabapples have rapidly entered full bloom and these oft-planted trees are truly spectacular this time of year. Unfortunately, after many spring-flowering trees and shrubs are finished with their spring display, they retreat to their role as unimpressive placeholders in the landscape (e.g. forsythia and overly-pruned weeping cherries). With better care, many of these plants could assume a greater stature for the rest of the year. Turf grasses are rapidly greening as soil temperatures continue to climb.

Pests/Problems: Despite temperatures dropping below freezing on 4/22, there appears to be only scattered and minor cases of frost injury on newly developing leaves and ephemeral flowers. The strong winds have resulted in damage of some tender shoots, on oak and maple, for example. As we enter May, fungal pathogens that cause foliar blights and stem cankers will begin attacking new growth on both deciduous and evergreen plants. Pruning dead stems from the canopy can help to reduce overwintering inoculum that initiates new infections. It’s always hard to predict if anthracnose diseases will be abundant and on what hosts. As foliage on maple and oaks mature, scout for angular-shaped, dark-colored lesions that are characteristic of anthracnose diseases. To date, no major foliar diseases have been observed but optimal weather conditions (mild and cloudy with scattered rain showers) for diseases like apple scab are now occurring. Skunks are actively digging in lawns for white grubs, voles and shrews are busy tunneling in landscape beds and rabbits continue to clip tender shoots and small stems. But overall, pest and pathogen activity remains low as temperatures slowly climb. Invasive plants like Japanese knotweed, multiflora rose, honeysuckle, and Japanese barberry, among others, are aggressively leafing out and growing at this time.

Berkshire Region (Great Barrington)

General Conditions: As of the morning of April 28, precipitation deficit is a little over 4 inches. According to the U.S. Drought Monitor, Berkshire County is currently in the abnormally dry category. Soil moisture levels are good where soils are heavy but at low levels otherwise. Besides the lack of precipitation, another factor of concern with regard to soil moisture, as well as tree damage, is the frequency of high wind events. Winds have been quite persistent this month; in some instances bringing down trees. Snow fell in many areas of the county during the overnight hours of April 21 and into the early morning hours of April 22. Snowfall in West Stockbridge and Richmond amounted to 2-3 inches. Little or no snow was seen elsewhere. The morning of April 22 saw a hard freeze; a low of 26˚F was recorded at the Pittsfield Airport. Growth of turfgrass has accelerated on sites with moderate soil moisture but has been growing slowly on drier soils. Dandelions, violets, and other common turf weeds are competing well with the grass.

Pests/Problems: The hard freeze of April 22 did cause some injury to plants. The damage was mostly to the flowers of early blooming azaleas and to the blossoms of Magnolias. The only plant disease observed was Volutella blight on Pachysandra. The plant pests found this week were spruce spider mite and boxwood leaf miner (still in the larval stage and actively feeding). Black flies, wasps, carpenter bees, and mosquitoes are active. Black-legged tick populations remain at very high levels. A common sight this spring has been the prevalence of trails in lawns left by meadow voles. The voles have been found to have fed on some 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 Tower Hill Botanic Garden, Boylston.
• PIONEER VALLEY REGION - Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, reporting from Amherst.
• BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

Recent pests and pathogens of interest seen in the UMass Extension Plant Diagnostic Lab (https://ag.umass.edu/services/plant-diagnostics-laboratory):

• The UMass Plant Diagnostic Lab often receives a number of rhododendron samples in the spring and this year is no different. Drought stress in 2020 combined with winter injury appears to have severely impacted a number of mature rhododendrons in the region. Foliage damaged by drought and cold temperatures is often colonized by opportunistic fungi, such as Phyllosticta and Pestalotiopsis. Established rhododendrons are often very drought-resistant but a lack of rain coupled with the extreme heat of 2020 has severely weakened many plants. Pruning out dead parts early in the season can help to limit the spread of foliar blights and stem cankering diseases.
• Decline of mature Catawba rhododendron (Rhododendron catawbiense) caused by drought stress, winter injury and Phyllosticta leaf blotch. A large and very old planting of rhododendrons, estimated around 60-years-old, growing on a west-facing slope. The plants are shaded by overstory oaks and sugar maples and soils are well-drained, consisting of a mixture of sand and loam. Submitted branch segments had foliage with a range of symptoms, which included: pale green in color, curled and desiccated; scattered brown to purple-colored spots; and, brown-colored marginal blight. Phyllosticta was abundant on the blighted leaf tissue. As a secondary pathogen, this fungus causes little to no damage on otherwise healthy plants but readily invades weakened and stressed tissues.
• Severe infestation of the boxwood leafminer (Monarthropalpus flavus) on an 150’ established hedge of Varder Valley boxwood (Buxus sempervirens ‘Varder Valley’). The plants are estimated to be 25-years-old and receive partial sun in soils that are considered excessively sandy. The residential property just changed owners and the new homeowner believed the damage to be drought stress. Closer inspection revealed a well-established infestation. The homeowner wants to attempt control without the use of insecticides, which will be challenging at this stage.
• Transplant shock and needle blight caused by Sydowia polyspora on white fir (Abies concolor). Five trees, approximately 10-years-old, that were planted in September of 2020 into a full sun landscape. The trees were planted in a southeast facing lawn area and were provided with regular irrigation since establishment. Submitted shoots had needles that were pale green to brown in color and appeared desiccated. The shock of transplant likely made the trees susceptible to winter injury. The fungal pathogen Sydowia can be regularly encountered on true firs (Abies spp.) in the region, causing a needle and shoot blight. This pathogen resembles Rhizosphaera and is easily confused.
• Premature needle shedding on blue spruce (Picea pungens) caused by Setomelanomma holmii. The tree is approximately 20-years-old and resides at a residential property in full sun. The landscaped bed is mulched and the tree was planted at a proper depth. One side of the tree is exhibiting dieback, which was not observed in the past. Submitted shoots had pale green, desiccated needles that were readily shedding. Setomelanomma colonizes the stems and the base of the needle, where it’s believed to cause water starvation and death of the needles. However, the fungus does not colonize the needles themselves.

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

Insects

Looking for more information about important arthropod vectors of human pathogens in Massachusetts? Don’t miss UMass Extension’s Tick and Mosquito Education Days!

June 8 & June 15 from 10:00 AM – 12:10 PM

This 2-day virtual webinar series will call upon topic experts to provide information about the seasonality, biology, and the diseases these organisms vector, as well as how to manage these pests and steps you can take to protect yourself.

June 8 – Tick Topics:

10:00 – 11:00 AM: Tick Management in the Landscape, Larry Dapsis, Cape Cod Cooperative Extension

11:10 AM – 12:10 PM: The Outreach Hiker’s Guide to Tick-ology: Personal tick bite prevention and more! Blake Dinius, Plymouth County Extension

June 15 – Mosquito Topics:

10:00 - 11:00 AM: Mosquitoes in Massachusetts, Arboviruses and Protecting Yourself, Dr. Jennifer Forman Orth, MA Dept. of Agricultural Resources

11:10 AM – 12:10 PM: Dealing with the Asian Tiger Mosquito: Incorporating an Invasive Species into an Existing Mosquito Control Program, Priscilla Matton, Superintendent, Bristol County Mosquito Control Project

For more information and to register, visit: https://ag.umass.edu/landscape/events/tick-mosquito-education-days

Insects and Other Arthropods

• Deer Tick/Blacklegged Tick: Check out the archived FREE TickTalk with TickReport webinars available here: https://ag.umass.edu/landscape/education-events/webinars .

*Ixodes scapularis adults have been active all winter, as they typically are from October through May, and “quest” or search for hosts at any point when daytime temperatures are above freezing. Engorged females survive the winter and will lay 1,500+ eggs in the forest leaf litter beginning around Memorial Day (late May). For images of all deer tick life stages, along with an outline of the diseases they carry, visit: http://www.tickencounter.org/tick_identification/deer_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: http://www.tickencounter.org/prevention/protect_yourself .

The UMass Laboratory of Medical Zoology is currently unable to accept samples for tick testing at this time. The Center for Agriculture, Food, and the Environment provides a list of potential tick identification and testing alternatives here: https://ag.umass.edu/resources/tick-testing-resources

*Note that deer ticks (Ixodes scapularis) are not the only disease-causing tick species found in Massachusetts. The American dog tick (Dermacentor variabilis) and the lone star tick (Amblyomma americanum) are also found throughout MA. Each can carry their own complement of diseases, including others not mentioned above. Anyone working or playing in tick habitats (wood-line areas, forested areas, and landscaped areas with ground cover) should check themselves regularly for ticks while practicing preventative measures.

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

Invasive Insects & Other Organisms Update:

• Spotted Lanternfly: (Lycorma delicatula, SLF) is not known to be established in Massachusetts landscapes at this time. However, due to the great ability of this insect to hitchhike using human-aided movement, it is important that we remain vigilant in Massachusetts and report any suspicious findings. Spotted lanternfly reports can be sent here: https://massnrc.org/pests/slfreport.aspx .

The Massachusetts Department of Agricultural Resources has recently released spotted lanternfly Best Management Practices for Nurseries and Landscapers: https://massnrc.org/pests/linkeddocuments/MANurseryBMPs.pdf

And Best Management Practices for Moving Companies and the Moving Industry: https://massnrc.org/pests/linkeddocuments/SLFChecklistMovingIndustryMA.pdf

Now is a great time to provide copies of these BMP’s to employees, customers, family, and friends! The more eyes we have out there looking for spotted lanternfly, the better. Spotted lanternfly egg masses overwinter, and are laid by these insects on just about any flat surface. Use the above BMP’s as a guide to help you inspect certain items coming from CT, DE, MD, NC, NJ, NY, OH, PA, WV, and VA.

UMass Extension is teaming up with UMass Amherst’s Department of Environmental Conservation, the USDA APHIS, and the Massachusetts Department of Agricultural Resources to monitor for the spotted lanternfly in Massachusetts. A team including members of UMass Extension’s Landscape, Nursery, and Urban Forestry Program, Extension’s Fruit Program, Stockbridge School of Agriculture, and the Department of Environmental Conservation at UMass, Amherst are undertaking a nine-month integrated research and extension project to develop effective tools to detect the spotted lanternfly.

The researchers associated with this project (Dr. Joseph Elkinton, Dr. Jeremy Andersen and Dr. Jaime Pinero) will be working with Dr. Miriam Cooperband of the USDA APHIS lab on Cape Cod to identify and evaluate airborne attractants that can improve the ability to detect SLF in traps. Dr. Cooperband has identified several attractant lures released from host plants of SLF. She is currently working on pheromones produced by SLF that may be much more attractive. The UMass team will help her conduct field tests of these new lures, while also assisting the Massachusetts Department of Agricultural Resources (MDAR) in monitoring for SLF in Massachusetts. UMass Extension Entomologist, Tawny Simisky, will periodically report on progress made during the course of this project. For more information, please visit: https://ag.umass.edu/cafe/news/looking-for-spotted-lanternfly-recent-invasive-arrival

This insect is a member of the Order Hemiptera (true bugs, cicadas, hoppers, aphids, and others) and the Family Fulgoridae, also known as planthoppers. The spotted lanternfly is a non-native species first detected in the United States in Berks County, Pennsylvania and confirmed on September 22, 2014.

For a map of known, established populations of SLF as well as detections outside of these areas where individual finds of spotted lanternfly have occurred (but no infestations are present), visit: https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/

The spotted lanternfly is considered native to China, India, and Vietnam. It has been introduced as a non-native insect to South Korea and Japan, prior to its detection in the United States. In South Korea, it is considered invasive and a pest of grapes and peaches. The spotted lanternfly has been reported feeding on over 103 species of plants, according to new research (Barringer and Ciafré, 2020) and when including not only plants on which the insect feeds, but those that it will lay egg masses on, this number rises to 172. This includes, but is not limited to, the following: tree of heaven (Ailanthus altissima) (preferred host), apple (Malus spp.), plum, cherry, peach, apricot (Prunus spp.), grape (Vitis spp.), pine (Pinus spp.), pignut hickory (Carya glabra), sassafras (Sassafras albidum), serviceberry (Amelanchier spp.), slippery elm (Ulmus rubra), tulip poplar (Liriodendron tulipifera), white ash (Fraxinus americana), willow (Salix spp.), American beech (Fagus grandifolia), American linden (Tilia americana), American sycamore (Platanus occidentalis), big-toothed aspen (Populus grandidentata), black birch (Betula lenta), black cherry (Prunus serotina), black gum (Nyssa sylvatica), black walnut (Juglans nigra), dogwood (Cornus spp.), Japanese snowbell (Styrax japonicus), maple (Acer spp.), oak (Quercus spp.), and paper birch (Betula papyrifera).

The adults and immatures of this species damage host plants by feeding on sap from stems, leaves, and the trunks of trees. In the springtime in Pennsylvania (late April - mid-May) nymphs (immatures) are found on smaller plants and vines and new growth of trees and shrubs. Third and fourth instar nymphs migrate to the tree of heaven and are observed feeding on trunks and branches. Trees may be found with sap weeping from the wounds caused by the insect’s feeding. The sugary secretions (excrement) created by this insect may coat the host plant, later leading to the growth of sooty mold. Insects such as wasps, hornets, bees, and ants may also be attracted to the sugary waste created by the lanternflies, or sap weeping from open wounds in the host plant. Host plants have been described as giving off a fermented odor when this insect is present.

Adults are present by the middle of July in Pennsylvania and begin laying eggs by late September and continue laying eggs through late November and even early December in that state. Adults may be found on the trunks of trees such as the tree of heaven or other host plants growing in close proximity to them. Egg masses of this insect are gray in color and look similar in some ways to gypsy moth egg masses.

Host plants, bricks, stone, lawn furniture, recreational vehicles, and other smooth surfaces can be inspected for egg masses. Egg masses laid on outdoor residential items such as those listed above may pose the greatest threat for spreading this insect via human aided movement.

For more information about the spotted lanternfly, visit this fact sheet: https://ag.umass.edu/landscape/fact-sheets/spotted-lanternfly .

• Emerald Ash Borer: (Agrilus planipennis, EAB) Since the New Year, the Massachusetts Department of Conservation and Recreation has confirmed at least 22 new community detections of emerald ash borer in Massachusetts. To date, 11 out of the 14 counties in Massachusetts have confirmed emerald ash borer. (The remaining counties where EAB has yet to be detected are Barnstable, Dukes, and Nantucket counties.)A map of these locations and others previously known across the state may be found here: https://ag.umass.edu/fact-sheets/emerald-ash-borer .

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). Adult insects of this species will not be present at this time of year. Signs of an EAB infested tree may include (at this time) D-shaped exit holes in the bark (from adult emergence in previous years), “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. Blonding on EAB infested ash has been particularly noticeable this winter in certain areas of Hampshire and Berkshire counties. Trees have been so heavily fed upon by woodpeckers that this change in the color of ash tree bark can be seen even while driving. (Monitoring for EAB this way is not recommended while operating your vehicle.) Particularly striking photos of blonding on ash caused by pileated woodpeckers were shared with UMass Extension from Lee, MA, courtesy of Cindy Packard on 2/13/2021. 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.

For further information about this insect, please visit: https://ag.umass.edu/fact-sheets/emerald-ash-borer . If you believe you have located EAB-infested ash trees, particularly in an area of Massachusetts not identified on the map provided, please report here: https://massnrc.org/pests/eabreport.htm .

• Winter Moth: (Operophtera brumata) data since 2017 has indicated that the winter moth population in eastern Massachusetts has been on the decline while the percent of winter moth pupae parasitized by Cyzenis albicans has increased! This is excellent news, as it is data supporting the evidence that winter moth populations have decreased while the parasitic fly, C. albicans, has become established at many locations in New England. Dr. Joseph Elkinton’s laboratory at UMass Amherst has released this biological control of winter moth since 2005 and conducted the rigorous sampling required to determine where the insect has established and what its impact on the winter moth population has been at multiple sites in eastern MA. More information about the Elkinton Lab’s research and the biological control of winter moth can be found here: https://www.fs.fed.us/foresthealth/technology/pdfs/FHAAST-2018-03_Biology_Control_Winter-Moth.pdf

The take-home point? Do not worry about winter moth this spring! In fact, management of this insect in landscaped settings will likely not be necessary in most locations. In recent years, it is worth-while to note that some areas on the Cape and other locations in eastern MA have reported noticeable cankerworm populations in the spring, which are often confused for winter moth. Read more about cankerworms in the spring scouting list below.

For blueberry growers in eastern Massachusetts concerned about winter moth, please visit this recent update from Heather Faubert, University of Rhode Island: https://web.uri.edu/ipm/2021/04/april-22-winter-moth-update/

• Gypsy Moth: (Lymantria dispar) thanks to the gypsy moth caterpillar killing fungus, Entomophaga maimaiga, the recent outbreak of gypsy moth in Massachusetts has come to an end! Most locations in Massachusetts will not see damaging or even noticeable populations of this insect in 2021. Gypsy moth has been in Massachusetts since the 1860's. This invasive insect from Europe often goes unnoticed, thanks to population regulation provided by the entomopathogenic fungus, E. maimaiga, as well as a NPV virus specific to gypsy moth caterpillars. (And to a lesser extent many other organisms, including other insects, small mammals, and birds who feed on gypsy moth.) However, if environmental conditions do not favor the life cycle of the fungus, outbreaks of gypsy moth caterpillars are possible. (Such as most recently from 2015-2018, with a peak in the gypsy moth population in 2017 in Massachusetts.)

Check out Episode 1 of InsectXaminer to reminisce about the 2015-2018 outbreak of this insect: https://ag.umass.edu/landscape/education-events/insectxaminer

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

The regulated area for Asian longhorned beetle is 110 miles² encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, please call the Asian Longhorned Beetle Eradication Program office in Worcester, MA at 508-852-8090 or toll free at 1-866-702-9938.

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

• White Spotted Pine Sawyer (WSPS): Monochamus scutellatus adults can emerge in late May throughout July, depending on local temperatures. This is a native insect in Massachusetts and is usually not a pest. Larvae develop in weakened or recently dead conifers, particularly eastern white pine (Pinus strobus). However, the white spotted pine sawyer looks very similar to the invasive Asian Longhorned Beetle, Anoplophora glabripennis, ALB. ALB adults do not emerge in Massachusetts until July and August. Beginning in July, look for the key difference between WSPS and ALB adults, which is a white spot in the top center of the wing covers (the scutellum) on the back of the beetle. White spotted pine sawyer will have this white spot, whereas Asian longhorned beetle will not. Both insects can have other white spots on the rest of their wing covers; however, the difference in the color of the scutellum is a key characteristic. See the Asian longhorned beetle entry above for more information about that non-native insect.
• Jumping Worms: In recent years, public concern about Amynthas spp. earthworms, collectively referred to as “jumping or crazy or snake” worms, has dramatically increased. University researchers and Extension groups in many locations in the US are finding that these species cause not only forest ecosystem disturbances, but may also negatively impact soil structure and reduce plant growth in gardens and managed landscapes. They do this by voraciously devouring the organic layer of the soil while feeding very close to the soil surface, unlike other species of earthworms. In woodland areas, they can quickly eat all of the leaf litter on the forest floor. Jumping worms also leave a distinct grainy soil full of worm castings. The soil becomes granular and may look like dried coffee grounds.

Unfortunately, there are currently no research-based management options available for these earthworms. So prevention is essential – preventing their introduction and spread into new areas is the best defense against them. Adult jumping worms can be 1.5 – 8 inches or more in length. Their clitellum (collar-like ring) is roughly located 1/3 down the length of the worm (from the head) and is smooth and cloudy-white and constricted. These worms may also wiggle or jump when disturbed, and can move across the ground in an S-shape like a snake. While the exact timing of their life cycle in MA might not be completely understood, their life cycle may be expected to go (roughly) something like this: they hatch in the late spring in 1-4 inches of soil, mature into adults during the summer and adults lay eggs sometime in August, and it is thought that their cocoons overwinter. (Adults perish with frost.) It is also worth noting here that jumping worms do not directly harm humans or pets.

For more information, listen to Dr. Olga Kostromytska’s presentation here: https://ag.umass.edu/landscape/education-events/invasive-insect-webinars

Additional resources can also be found here:

University of Minnesota Extension: https://extension.umn.edu/identify-invasive-species/jumping-worms

Cornell Cooperative Extension: http://ulster.cce.cornell.edu/environment/invasive-pests/jumping-worm

UNH Extension: https://extension.unh.edu/blog/invasive-spotlight-jumping-worms

Spring Scouting & Preparation for Upcoming Tree & Shrub Insects & Mites:

• 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. Now is the time to scout for and remove and destroy overwintering bags. In certain areas across MA in 2020, increased populations of bagworms were observed and reported, particularly in urban forest settings and managed landscapes. More information can be found here: https://ag.umass.edu/landscape/fact-sheets/bagworm
• Balsam Twig Aphid: Mindarus abietinus overwinters as a silvery colored egg on host plant twigs. Eggs hatch just prior to budbreak and nymphs feed for a period of time on the undersides of last season’s needles before molting into a wingless stem mother. Stem mothers move to buds just as they open and give “live birth” to second generation nymphs. These second generation nymphs are the most damaging, feeding on new needles as they elongate, causing distortion and stunting. Excessive amounts of honeydew may be produced and cause needles to stick together. Foliar applications, if needed, may be made between 30-100 GDD’s, base 50°F on warm days before budcaps loosen. Inspect the twigs, near the base of needles of Balsam fir, Fraser fir, and other true firs for overwintering eggs and eventually the needles for feeding nymphs. This insect may be most problematic in Christmas tree production. In landscapes, many natural enemies can provide adequate management of this insect.
• Boxwood Leafminer: Monarthropalpus flavus partly grown fly larvae overwinter in the leaves of susceptible boxwood. Yellowish mines may be noticeable on the undersides of leaves. This insect grows rapidly in the spring, transforming into an orange-colored pupa. After pupation, adults will emerge and white colored pupal cases may hang down from the underside of leaves where adults have emerged. Adults may be observed swarming hosts between 300-650 GDD’s, or roughly the end of May through June. Most cultivars of Buxus sempervirens and B. microphylla are thought to be susceptible. If installing new boxwoods this spring, resistant cultivars such as ‘Vardar Valley’ and ‘Handsworthiensis’ are good choices at sites where this insect has been a problem.
• Boxwood Mite: Eurytetranychus buxi overwinter as tiny eggs on boxwood leaves and hatch mid-spring. These mites are tiny (about the size of a period) and difficult to detect. Feeding may cause plants to appear off-color. If management is deemed necessary, the timing for treatment may be between 245-600 GDD’s or roughly the beginning of May.
• Boxwood Psyllid: Psylla buxi feeding can cause cupping of susceptible boxwood leaves. Leaf symptoms/damage may remain on plants for up to two years. English boxwood may be less severely impacted by this pest. Eggs overwinter, buried in budscales, and hatch around budbreak of boxwood. Eggs may hatch around 80 GDD’s. Foliar applications may be made between 290-440 GDD’s. However, the damage caused by this insect is mostly aesthetic. Therefore, no management may be necessary.
• Cankerworms: Alsophila pometaria (fall cankerworm) and Paleacrita vernata (spring cankerworm) are often confused for winter moth (Operophtera brumata). Cankerworm populations in eastern MA, particularly on areas of Cape Cod, were confused for winter moth in 2019. Spring cankerworm adults are active in February and March, and fall cankerworm adults are active in late November into early December. During these times, both species lay eggs. These native insects most commonly utilize elm, apple, oak, linden, and beech. Eggs of both species hatch as soon as buds begin to open in the spring. Caterpillars occur in mixed populations and are often noticeable by mid-May in MA. Young larvae will feed on buds and unfolding leaves. There are two color forms (light green and dark) for caterpillars of both species. Like winter moth, they will drop to the soil to pupate. This usually occurs in June. Fall cankerworm larvae have three pairs of prolegs (one of which is small so it is sometimes referred to as ½) and spring cankerworm have two pairs. (Winter moth caterpillars also have 2 pairs of prolegs.) If populations are large and damage is noticeable on hosts, reduced risk insecticides such as Bacillus thuringiensis Kurstaki or spinosad may target larvae between 148-290 GDD’s.
• Cooley Spruce Gall Adelgid: Adelges cooleyi is a native insect that has a complex life cycle. It has at least five different morphological forms, and requires 2 years and two hosts to complete its normal life cycle. Galls (pineapple shaped/cone-like and at the tips of twigs) are produced on Colorado blue spruce, Engelmann, Sitka, and Oriental spruce and cause needle injury (yellow spots and distortion) to Douglas-fir. Immature females overwinter on spruce near twig terminals. In the early spring, females mature into stem mothers and lay hundreds of eggs on lateral terminals. Upon egg hatch, nymphs migrate to new spring growth and feed at the base of growing needles. Immatures can be targeted on spruce between 22-81 GDD’s (mid-late April). On Douglas-fir, dormant oil applications should be made immediately before budbreak to avoid phytotoxicity. Follow all label instructions.
• Dogwood Borer: Synanthedon scitula is a species of clearwing moth whose larvae bore not only into dogwood (Cornus), but hosts also include flowering cherry, chestnut, apple, mountain ash, hickory, pecan, willow, birch, bayberry, oak, hazel, myrtle, and others. Kousa dogwood appear to be resistant to this species. Signs include the sloughing of loose bark, brown frass, particularly near bark cracks and wounds, dead branches, and adventitious growth. The timing of adult emergence can be expected when dogwood flower petals are dropping and weigela begins to bloom. Adult moth flights continue from then until September. Emergence in some hosts (ex. apple) appears to be delayed, but this differs depending upon the location in this insect’s range. Eggs are laid singly, or in small groups, on smooth and rough bark. Female moths preferentially lay eggs near wounded bark. After hatch, larvae wander until they find a suitable entrance point into the bark. This includes wounds, scars, or branch crotches. This insect may also be found in twig galls caused by other insects or fungi. Larvae feed on phloem and cambium. Fully grown larvae are white with a light brown head and approx. ½ inch long. Pheromone traps and lures are useful for determining the timing of adult moth emergence and subsequent management.
• Eastern Spruce Gall Adelgid: Adelges abietis is a pest of Norway spruce primarily, but occasionally damages other spruce species such as Colorado blue, white, and red spruce. This adelgid overwinters as a partially grown female, often referred to as a stem mother. This overwintering individual matures around bud break and lay 100-200 eggs. The eastern spruce gall adelgid may be targeted for management between 22-170 GDD’s, base 50°F (mid-April to early-May). This insect is non-native, and was introduced into the United States from Europe before 1900. Galls are small, sometimes pineapple shaped/variable, but produced on the basal portion of the shoots, such that the twig extends beyond the gall. Twig dieback may occur.
• Eastern Tent Caterpillar: Malacosoma americanum eggs overwinter on host plant twigs. Egg hatch typically occurs when wild cherry leaves begin to unfold and young caterpillars may emerge by late-April through the first two weeks in May (90-190 GDD’s). Susceptible hosts include cherry and crabapple. Other host plants whose leaves are fed upon by this native insect can include apple, ash, birch, willow, maple, oak, poplar, and witch-hazel. Prune off and remove egg masses from ornamental host plants by early spring. Eastern tent caterpillars are native to Massachusetts and have many associated natural enemies (parasites and predators) that help regulate populations. Unless these caterpillars are actively defoliating specimen trees in a landscaped setting, we can coexist with this particular herbivore native to our forests.
• Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. The elongate hemlock scale may overwinter in various life stages, and overlap of many developmental stages at any given time can be observed throughout much of the season. Dormant oil applications for this pest can occur according to label instructions in April, roughly between 7-120 GDD’s. Treatments for the crawler, or mobile, stage of this insect may be made in late May through mid-June, or between 360-700 GDD’s, base 50°F. Nitrogen fertilizer applications may make elongate hemlock scale infestations worse.
• Euonymus Scale: Unaspis euonymi is an armored scale that can be found on euonymus, holly, bittersweet, and pachysandra. This insect can cause yellow spotting on leaves, dieback, and distorted bark. Dormant oil applications can be made between 35-120 GDD’s or roughly from mid-April to early-May. For crawlers, early June timing is suggested between 533-820 GDD’s. (Eggs begin to hatch in early June.)
• European Pine Sawfly: Neodiprion sertifer overwinters in the egg stage. Eggs are laid by females the previous season by cutting slits in needles using their ovipositors and depositing 6-8 eggs in each of 10-12 needles. Egg hatch occurs from late-April to mid-May and caterpillars become active roughly between 78-220 GDD, base 50°F. The primary host in MA is Mugo pine but it can be found on Scots, red, jack, and Japanese red pine. It is also found on white, Austrian, ponderosa, shortleaf, and pitch pine when planted near the aforementioned species. This dark colored caterpillar feeds in tight groups and small numbers can be pruned or plucked out of host plants and destroyed. Spinosad products can be used whenever the caterpillars are actively feeding, usually by mid-May and when caterpillars are still small. Bacillus thuringiensis kurstaki is not effective against sawflies.
• Fletcher Scale: Parthenolecanium fletcheri is a soft scale pest of yew, juniper, and arborvitae. Feeding scales, especially on yew, result in honeydew and sooty mold, needle yellowing, and at times, premature needle drop. There is one generation per year. Overwintered second instar nymphs can be targeted between 38-148 GDD’s, base 50°F. Nymphs develop and adult females lay eggs (on average 500-600) in May that hatch by June. Dead females conceal egg masses beneath. Crawlers migrate short distances to branches and may be concentrated on certain branches of a particular plant.
• Forest Tent Caterpillar: Malacosoma disstria egg hatch occurs between 192-363 GDD’s, base 50°F, by mid-late May and caterpillars may be active for at least 5-6 weeks following. Susceptible hosts whose leaves are fed on by this insect include oak, birch, ash, maple, elm, poplar, and basswood. This native insect has many natural enemies, including some very effective pathogens that typically regulate populations. However, outbreaks of this insect can occur on occasion.
• Hemlock Looper: Two species of geometrid moths in the genus Lambdina are native insects capable of defoliating eastern hemlock, balsam fir, and white spruce. Adult moths lay their eggs on the trunk and limbs of hosts in September and October, and eggs will hatch by late May or early June. (L. fiscellaria caterpillars may be active between 448-707 GDD’s.) Monitor susceptible hosts for small, inch-worm like caterpillars. Where populations are low, no management is necessary. Hemlock loopers have several effective natural enemies.
• Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. The overwintering hemlock woolly adelgid generation (sistens) is present through mid-spring and produces the spring generation (progrediens) which will be present from early spring through mid-summer. HWA, unlike many other insects, does most of its feeding over the winter. Eggs may be found in woolly masses at the base of hemlock needles beginning in mid-March. Each woolly mass is created by a female who may then lay 50-300 eggs. Eggs hatch and crawlers may be found from mid-March through mid-July. Infested trees may be treated with foliar sprays in late April to early May, using Japanese quince as a phenological indicator. Systemic applications may be made in the spring and fall, or when soil conditions are favorable for translocation to foliage. Nitrogen fertilizer applications may make hemlock woolly adelgid infestations worse.
• Honeylocust Plant Bug: Diaphnocoris chlorionis feeding results in tiny yellowish-brownish spots on leaves, leaf distortion, and in some cases, defoliation. (There are at least 7 species of plant bugs that feed on honeylocust, Gleditsia triacanthos.) There is one generation per year. Immatures and adults feed on foliage and light to moderately damaged foliage may persist throughout the growing season. Honeylocust plant bugs overwinter as eggs laid just beneath the bark surface of 2 and 3-year old twigs. Eggs hatch just after vegetative buds of the host begin to open. Young nymphs crawl to the opening leaflets and begin feeding and the most significant damage occurs at that time, when the insect is hidden from view. Nymphs develop into adults around May-July. This insect can be targeted between 58-246 GDD’s, base 50°F.
• Imported Willow Leaf Beetle: Plagiodera versicolora adult beetles overwinter near susceptible hosts. Adult beetles will chew holes and notches in the leaves of willow once they become available. Females lay yellow eggs in clusters on the undersides of leaves. Larvae are slug-like and bluish-green in color. They will feed in clusters and skeletonize the leaves. Most plants can tolerate 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: https://ag.umass.edu/landscape/education-events/insectxaminer

• Lecanium Scales (Oak): Parthenolecanium quercifex overwinters as a second instar nymph on oak twigs. Females will begin feeding and mature in the spring, from mid-April to early May and eggs may be laid between late May and into June. Eggs hatch in June or early July and crawlers migrate to host plant leaves where they spend the summer and migrate as second instars back to host plant twigs in the fall. Mid-April to early-May (35-145 GDD’s) for dormant oil applications.
• Lilac Borer: Podosesia syringae is a clearwing moth pest of lilac, privet, fringetree, and ash. (It is also known as the ash borer, not to be confused with the emerald ash borer.) Adults mimic paper wasps. Larvae are wood-boring, and signs and symptoms include branch dieback, holes, and occasionally, sawdust-like frass accumulated on bark. Larvae bore into stems, trunks, and branches, chewing an irregularly shaped entrance hole. Peak adult moth flights may occur in the northern portion of this insect’s range in June and is usually over by August 1^st. Pheromone traps can be used to time adult emergence. Adult females lay flattened, oval, and tan eggs that are deposited singly or in clusters on bark crevices, ridges, and sometimes smooth bark; but usually laid in or near wounds in the bark. On average, 395 eggs are laid by each female. After hatch, larvae chew into the bark and feed laterally and then vertically in phloem tissue. Larvae overwinter in tunnels in the final instar and resume feeding in the spring. Adults emerge through a round exit hole (4-5 mm. in diameter). This insectmay be targeted between 200-299 GDD’s, base 50°F.
• Lily Leaf Beetle: Lilioceris lilii adults overwinter in sheltered places. As soon as susceptible hosts such as Lilium spp. (Turk’s cap, tiger, Easter, Asiatic, and Oriental lilies) and Fritillaria spp. break through the ground, the adult lily leaf beetles are known to feed on the new foliage. (Note: daylilies are not hosts.) Typically, in May, mating will occur and each female will begin to lay 250-450 eggs in neat rows on the underside of the foliage. If there are only a few plants in the garden, hand picking and destroying overwintering adults can help reduce local garden-level populations at that time.

Check out Episode 3 of InsectXaminer to see the lily leaf beetle in action: https://ag.umass.edu/landscape/education-events/insectxaminer

• Magnolia Scale: Neolecanium cornuparvum overwinters as first instar nymphs which are elliptical, and dark slate gray in color and can usually be found on the undersides of 1 and 2 year old twigs. Nymphs may molt by late April or May and again by early June at which time the scales may be purple in color. Eventually nymphs secrete a white powdery layer of wax over their bodies. Dormant oils can be applied between 7-35 GDD’s targeting the overwintering nymphs. Avoid applications to opening buds or blooms.
• Pine Bark Adelgid: Pineus strobi overwinters as an immature which begins feeding during the first days of warm weather in the spring and begins secreting white wax over itself, which can eventually coat the entire trunk of infested trees. Egg laying may begin in April. This insect can be found on the trunk, branches, twigs, and the base of needles on new shoots. Spruce is a secondary host but this adelgid can repeatedly reproduce itself on pine. Wash off bark with a strong jet of water. If necessary, dormant oil applications can be made in mid-late April between 22-58 GDDs. Hosts include eastern white, Scots, and Austrian pines. This insect does little damage to healthy trees and can often be tolerated.
• Snowball Aphid: Neoceruraphis viburnicola eggs overwinter on viburnum twigs and buds. Eggs hatch and this aphid becomes active on certain species of viburnum roughly between 148-298 GDD’s or around redbud bloom. This insect is particularly noticeable on V. opulus, V. prunifolium, and V. acerifolia. Stem mothers, appearing blueish-white, can be found in curled up and distorted foliage. Damage caused by this insect pest is mostly aesthetic.
• Spruce Bud Scale: Physokermes piceae is a pest of Alberta and Norway spruce, among others. Immatures overwinter on the undersides of spruce needles, dormant until late March. By April, females may move to twigs to complete the rest of their development. Dormant oil applications may be made between 22-121 GDDs. Follow all label instructions, as oil may remove the bluish color from certain conifers. Mature scales are reddish brown, globular, 3 mm. in diameter, and found in clusters of 3-8 at the base of new twig growth. They closely resemble buds and are often overlooked. Crawlers are present around June.
• Spruce Spider Mite: Oligonychus ununguis is a cool-season mite that becomes active in the spring from tiny eggs that have overwintered on host plants. Hosts include spruce, arborvitae, juniper, hemlock, pine, Douglas-fir, and occasionally other conifers. This particular species becomes active in the spring and can feed, develop, and reproduce through roughly June. When hot, dry summer conditions begin, this spider mite will enter a summer-time dormant period (aestivation) until cooler temperatures return in the fall. This particular mite may prefer older needles to newer ones for food. When damaging spruce spider mite populations are known from last season, dormant oil applications can be made (when temperatures are appropriate according to label instructions) between 7-121 GDD’s, base 50°F (April). Magnification is required to view spruce spider mite eggs. Tapping host plant branches over white paper may be a useful tool when scouting for spider mite presence. (View with a hand lens.) Spider mite damage may appear on host plant needles as yellow stippling and occasionally fine silk webbing is visible.

Spruce spider mite populations may again build (with subsequent generations) in mid-late May (192-363 GDD’s) and again in late August to mid-September (2375-2806 GDD’s). Continue to scout for spruce spider mites by tapping branches over a white piece of paper or other white surface, then viewing them with a hand lens or other magnification. A general rule of thumb is that if 10 or more spruce spider mites are found per branch (in the absence of predatory mites), chemical management might be necessary (if you are also seeing roughly 10% of the foliage with stippling/discoloration). However, if you are finding light-colored and tear-drop shaped and fast-moving predatory mites, at a ratio of approximately 1 predatory mite: 10 spruce spider mites, these beneficial insect relatives may be able to help naturally keep spruce spider mite populations below damaging levels. It is important to also scout for predatory mites and beneficial insects (hoverfly larvae, lacewing larvae, and lady beetle larvae and adults) while scouting for spruce spider mites, because knowledge of the presence of these beneficial predators will impact your management decisions. Broad spectrum insecticides should not be used to manage spruce spider mites on host plants where predatory mites are present as these chemicals could kill the predatory mites and lead to a subsequent surge in spruce spider mite populations.

• Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. Viburnum leaf beetle overwinters as eggs laid in capped pits on the newest growth of susceptible viburnum branches. Scout for overwintered eggs and prune out and destroy before they hatch. Egg hatch occurs in late-April to early-May as temperatures warm and foliage becomes available. Monitor for larvae in mid-May (80-120 GDD’s). 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/ .
• White Pine Weevil: Pissodes strobi adults overwinter in sheltered locations in the leaflitter and become active very early in the spring, when daytime temperatures reach 50°F and before the bloom of forsythia (between 7-58 GDDs). Hosts include eastern white pine, Norway spruce, scotch, pitch, and red pine, blue spruce, and white spruce are also susceptible to white pine weevil damage. Adults will begin feeding on bark 7-10 inches below dormant terminal buds. Females will deposit eggs in terminal growth bark, and developing larvae will feed in leaders until they mature in July when pupation occurs in pupal chambers made of wood chips. Management in nurseries or Christmas tree production may be necessary. Target adults between 7-58 GDD’s.
• Woolly Elm Aphid: Eriosoma americanum females lay a single egg in the cracks and crevices of elm bark, where the egg overwinters. Eggs hatch on elm in the spring as leaves are unfolding. Aphids may be active from 121-246 GDD’s, base 50°F on elm. A young, wingless female hatched from the egg feeds on the underside of leaf tissue. This female aphid matures and gives birth to 200 young, all females, without mating. These aphids feed, and the elm leaf curls around them and protects them. By the end of June, winged migrants mature and find serviceberry hosts. Another set of females is produced. These new females crawl to and begin feeding on the roots of serviceberry. Multiple generations occur on the roots of serviceberry through the summer.

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

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

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