Landscape Message: May 29, 2020

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.

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 May 27, 2020. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2020 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	2020 Total	Sun	Shade
CAPE	58	134.5	63	56	0.26	12:00 PM 5/27
SOUTHEAST	68.5	170.5	81	63	0.01	3:30 PM 5/27
NORTH SHORE	74.5	186.5	66	57	0	3:30 PM 5/27
EAST	81	221.5	73	64	0	5:00 PM 5/27
METRO	75.5	191.5	63	58	0.02	6:00 AM 5/27
CENTRAL	85	199	58	56	0	7:15 AM 5/27
PIONEER VALLEY	92.5	210	69	54	0.04	2:00 PM 5/27
BERKSHIRES	96.5	192	65	60	0.02	8:30 AM 5/27
AVERAGE	79	188	67	58	0.04	_
n/a = information not available

A map of Massachusetts for reference during dry conditions:  https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?MA

Phenology

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT	CAPE	SE	NS	EAST	METRO	CENT	PV	BERK
Enkianthus campanulatus (redvein Enkianthus)	*	*	*	*	*	Begin	Begin	Begin
Aesculus hippocastanum (common horsechestnut)	*	Begin	Begin	Begin	Begin	Begin	Begin/Full	Begin
Rhododendron carolinianum (Carolina Rhododendron)	Begin/Full	*	*	Begin	Begin	Begin	Begin	*
Rhododendron catawbiense (Catawba Rhododendron)	Begin	Full	Begin	Begin	Begin	Begin	Begin	*
Spiraea x vanhouttei (Vanhoutte Spirea)	Full	*	Full	Begin	Full	Full	Full	Begin
Elaeagnus umbellata (autumn olive)	Full	Full	Full	Full	Full/End	Full	Full	Begin
Syringa vulgaris (common lilac)	Full	Full	Full	Full/End	Full/End	Full/End	Full	Full
Cornus florida (flowering dogwood)	Full/End	End	End	Full	Full	Full	Full	Full
Rhododendron spp. (early azaleas)	Full/End	End	End	Full/End	Full/End	Full	Full/End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature during the period was 57˚F with a high of 75˚F on May 22 and a low of 35˚F on May 21. In the past week only about a quarter of an inch of precipitation fell. Topsoil moisture is short, sub soil moisture is adequate. Signs of water stress on droughty unirrigated lawns is already being observed. Make sure to water recently planted trees, shrubs and flowers frequently.

Pests/Problems: Honeydew from lecanium scale is starting to make a sticky mess. Under heavily infested trees the understory plants are glistening with fresh honeydew. The scales are slowly developing the more hemispherical shape of the adult females. The ideal treatment window for dormant oil is closing (35-145 GDD base 50). Winter moth can be seen ballooning around and causing minor damage to some trees. Other insects or insect pest seen during the period include eastern tent caterpillar on black cherry, Hydrangea leaftier on smooth Hydrangea, Viburnum leaf beetle larvae on arrowwood, boxwood psyllid on boxwood, white prunicola scale on lilac, possible Rhododendron gall midge damage on Rhododendron (previous year) and elder shoot borer moth larvae on elderberry ‘Black Lace’ (see photos).

Disease symptoms or signs seen during the period include black spot on rose and defoliation of mountain laurel from leaf spot (possibly Phyllosticta). The dry conditions are welcomed by those struggling with high disease pressure the last couple of years. Other damage seen during the period includes herbicide damage to turf (chlorosis from possibly mesotrione?) and annual leaf drop on American holly which is often mistaken for disease as the leaves turn yellow and often have black spots before abscising. Weeds in bloom include garlic mustard (Alliaria petiolata), black medic (Medicago lupulina), cypress spurge (Euphorbia cyparissias), chickweed (Stellaria media), white clover (Trifolium repens), and cinquefoil (Potentilla simplex). There is an abundance of rabbits and black legged ticks!!!

Southeast Region (Dighton)

General Conditions: For the second week lately, precipitation has been meager. Warmer weather will result in drought stress unless we have rain. The following plants are in flower: Aesculus hippocastanum (horsechestnut), Aquilegia spp.(columbine), Iris germanica (bearded Iris), Geranium maculatum (wild Geranium), Allium spp., Leucanthemum x superbum (Shasta daisy), Lamprocapnos spectabilis (bleeding heart), Vaccinium corymbosum (highbush blueberry), Rhododendron spp., Lupinus polyphyllus (lupine), Rosa rugosa (beach rose), Dianthus deltoides (pinks), Cornus florida (flowering dogwood),C. servicea (redosier dogwood), Spirea spp. (bridal wreath), Convallaria majalis (lily of the valley), Viburnum plicatum var. tomentosum (doublefile Viburnum), Hyacinthoides hispanica (wood Hyacinth), Prunus serotina (black cherry), Weigela, Lunaria annua (honesty), Syringa spp. (lilacs), Phlox stolonifera (creeping Phlox), Arisaema triphyllum (Jack in the pulpit), Polygonatum commutatum (Solomon's seal), Papaver orientale (Oriental poppy), Ajuga reptans (bugleweed), and Wisteria spp.

Pests/Problems: Black spot was observed on rose ‘New Dawn’. There seems to be a deficit of tree leaf eating caterpillars locally. Newly emerged leaves of oaks and maples are largely intact. I haven't even noticed the usually ubiquitous Eastern tent caterpillar. Some invasive weeds seen in bloom include Hesperis matronalis (dame's rocket), Lonicera maackii (Amur honeysuckle), Elaeagnus umbellata (autumn olive), and Ornithogalum umbellatum (star of Bethlehem). Anecdotally, there is a bumper crop of Japanese knotweed seedlings this year. They have their second set of true leaves now. (See Weed report below).

North Shore (Beverly)

General Conditions: This reporting period was sunny, dry and warm with very little cloud cover. The average daily temperature for this period was 60˚F. The highest temperature during this reporting period was 82˚F, recorded on May 22, and the lowest temperature was 42˚F recorded on May 24. There has been no rain recorded for the last 10 days. The top soil is dry but the subsoil is still moist. Grass on sunny dry areas is showing signs of water stress. Water those areas of the lawn if possible. Recently planted trees, shrubs and perennials should also be watered. Many plants were in bloom during this period. Some woody plants observed in bloom include: horse chestnut (Aesculus hippocastanum), dove tree (Davidia involucrata), common lilac (Syringa vulgaris), S. pubescens subsp. microphylla ‘Superba’ (littleleaf lilac), Wisteria (Wisteria floribunda), silver bell (Halesia carolina), Fothergilla (Fothergilla major), golden chain tree (Laburnum anagyroides), redbud (Cercis canadensis), Alabama snow wreath(Neviusia alabamensis) and tree peony (Paeonia suffruticosa). Herbaceous plants in bloom include: columbine (Aquilegia canadensis), Japanese primrose (Primula japonica), doll’s eyes/white baneberry (Actaea pachypoda), Allium (Allium spp.) honesty plant (Lunaria annua), Trillium (Trillium spp.) and fetterbush (Leucothoe fontanesiana).

Pests/Problems: Leaf and flower gall disease (Exobasidium vaccinii) was observed in azalea. The fungus causes cells in leaf and flower tissue to multiply rapidly forming large fleshy galls. The disease can be controlled by hand picking the galls and burning or burying them. To prevent new infections, pick the galls before the white spore layer appears. Rose sawfly was observed causing damage to rose bushes. If larvae are discovered when they are still young, they can easily be controlled by an insecticidal spray. Make sure to spray both sides of the leaves. The larvae of Viburnum leaf beetles (Pyrrhalta viburni) are getting larger and starting to cause damage on the leaves of susceptible Viburnum cultivars. Dandelion (Taraxacum officinale) seeds are maturing and being blown over the landscape by wind. Other spring weeds seen in bloom include: sweet woodruff (Galium odoratum), violets (Viola spp.), ground ivy (Glechoma hederacea), garlic mustard (Alliaria petiolata) and dead nettle (Lamium purpureum). Take measures to control weeds before they set seed. Mosquitoes and ticks are very active - protect yourself with repellents when working outdoors!

East Region (Boston)

General Conditions: This past week has been sunny, dry and warm. We had a daytime high temperature of 86°F on the 27th and a low of 56°F on the 24th. On the 24th we reached the high temperature of the day, 70°F at 6:00 AM! The lowest overnight low of 39°F also occurred on the 24th. We gained 81GDDs over the last week to bring the total to 221.5 for the year. Low temperatures ranged from 39°F to 52°F, averaging 46°F. High temperatures ranged from 56°F to 86°F, averaging 71°F. We received no precipitation over this reporting period. Several plants in bloom include; Cornus florida (dogwood), Halesia caroliniana (Carolina silverbell), Paeonia rockii (Rock's peony), Vaccinium corymbosum (northern highbush blueberry), and Wisteria. The Aesculus (horsechestnuts and buckeyes) are putting on a show, notably Aesculus pavia (red buckeye) with its large red flower spikes.

Pests/Problems: We have not received precipitation in 11 days. Soils are rapidly drying out and pollen count in the air is high. Hydrangea leaftier is continuing its activity of sewing up terminal leaves and buds of susceptible Hydrangea. The curled-up leaves of Viburnum, especially prevalent on V. carlesii (Koreanspice Viburnum), was likely caused by the black bean aphid (Aphis fable). The few winter moth (Operophtera brumata) that survived parasitism from the parasitic fly Cyzenis albicans are beginning to balloon. Pachysandra leafblight caused by the fungus Volutella pachysandra is evident on stressed Pachysandra.

Metro West (Acton)

General Conditions: We experienced some summer-like temperatures during this reporting period. There were three days with temperatures recorded in the 80’s. A high temperature of 86°F on the 26^th and scant precipitation was recorded. The average monthly rainfall for May is 4.04” but as of the 26^th, only 1.85” has been recorded for this area. Despite lack of rain, the landscape is exploding with color! Observed in some stage of bloom this past week were the following woody plants: Aesculus hippocastanum (horsechestnut), Aronia arbutifolia (black chokecherry), Cercis canadensis (redbud), C. canadensis var. “Alba” (white flowering redbud), Cornus florida (dogwood), C. x rutgersensis 'Ruth Ellen' (Rutgers hybrid dogwood), Cornus sericea (redosier dogwood), Daphne x burkwoodii 'Carol Mackie' (Daphne), Fothergilla gardenii (dwarf Fothergilla), F. major (large Fothergilla), Halesia carolina ‘Arnold Pink’ (Arnold pink silverbell), Halesia tetraptera (mountain silverbell), Ilex aquifolium (English holly), Kerria japonica ‘Pleniflora’ (Japanese double flowering form Kerria), Leucothoe axillaris (coast Leucothoe), Lonicera maackii (Amur honeysuckle), Prunus serotina (black cherry), Rhododendron spp. (Rhododendron and azalea), Spiraea spp. (bridal wreath), Syringa spp. (lilac), Vaccinium angustifolium (lowbush blueberry), V. corymbosum (highbush blueberry), Viburnum plicatum var. tomentosum (doublefile Viburnum), V. sargentii (Sargent Viburnum), and Weigela florida (old fashioned Weigela).

Woody vines in bloom are: our native, hummingbird-loving Lonicera sempervirens (trumpet honeysuckle) and Wisteria spp. (Wisteria). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Actaea pachypoda (white baneberry), Ajuga reptans (bugleweed), Alchemilla mollis (lady’s mantle), Allium spp. (ornamental flowering onion), Aquilegia canadensis (native columbine), Aquilegia spp.(columbine cultivars), Amsonia hubrichtii (Arkansas blue star), Arisaema triphyllum (Jack-in-the-pulpit), Aurinia saxatilis (basket of gold), Brunnera macrophylla (Siberian bugloss, great forget-me-not, heartleaf, alkanet), Camassia scilloides (wild Hyacinth, Atlantic camas), Chrysogonum virginianum (green and gold), Convallaria majalis (lily of the valley), Dianthus deltoides (maiden pink), Dicentra eximia (fringed bleeding heart), D. spectabilis (old fashioned bleeding heart), D. spectabilis ‘Alba’ (white old fashioned bleeding heart), Dodecatheon meadia (shooting star), Epimedium x versicolor 'Sulphureum' (yellow flowering barrenwort), Gallium odoratum (sweet woodruff), Geranium maculatum (wild Geranium), G. macrorrhizum (bigroot Geranium), G. sanguineum (cranesbill Geranium), Hyacinthoides hispanica (wood Hyacinth), Iris germanica (bearded Iris), Linaria annua (money plant), Lupinus 'Russell Woodfield Hybrids' (lupine), Myosotis sylvatica (forget-me-not), Nepeta spp. (ornamental catmint), Paeonia spp. (peony), Phlox divaricata (Canadian Phlox), P. stolonifera (creeping Phlox), P. x subulata (moss Phlox), Podophyllum peltatum (Mayapple), Polemonium reptans (Jacob’s ladder), Polygonatum commutatum (great Solomon’s seal), P. odoratum 'Variegatum' (variegated Solomon’s seal), Sibbaldiopsis tridentata, formerly Potentilla tridentata (three leaf cinquefoil), Primula spp. (primrose), Stylophorum diphyllum (wood/celandine poppy), Tiarella cordifolia (foam flower), Veronica umbrosa ‘Georgia Blue’ (speedwell), Waldsteinia ternata (barren strawberry), and Zizia aptera (heart-leaved golden Alexanders).

Pests/Problems: Soils are dry with the serious lack of significant rain fall this month. Forecasters are predicting rain for later this week so hopefully as this message is received and read, we will receive enough so this will no longer be the case! Observed in the landscape this past week were cedar-apple rust fruiting fungal bodies on Juniperus virginiana (Eastern redcedar), snowball aphid on Viburnums, caterpillars feeding on the foliage of Cercis (redbud) and Corylus (filbert), and leaf spot on Malus (crabapple). Toxicodendron radicans (poison ivy) continues to leaf out and it is fairly easy to detect its shiny red leaves of three. (See Weed report below.) Ticks, mosquitoes and black flies are feeding and increasingly active.

Central Region (Boylston)

General Conditions: I guess the weather in New England should never surprise any of us, but nearly touching 90˚F on the final day of this reporting period was nothing but shocking. After a long, cool, start to spring, we seem to have quickly jumped to summer and are already hoping for precipitation to return. There were ample flowering plants in bloom this week, including many native species, such as Cypripedium acaule (pink lady’s slipper), Geranium maculatum (wild Geranium), Houstonia caerulea (bluets or Quaker ladies), Iris cristata (woodland Iris), Rhododendron prinophyllum (early azalea), and Tiarella cordifolia (foam flower). Non-native garden species flowering in abundance this week include many hybrid azaleas, the start of the large leaf, broadleaved, evergreen Rhododendrons, common lilac (Syringa vulgaris), cutleaf lilac or Persian lilac (Syringa × persica - a hybrid between S. afghanica and S. x laciniata), Deutzia hybrids, Weigela floribunda (flowering Weigela), Iris germanica (bearded Iris), Paeonia spp. and hybrids, Spanish bluebells (Hyacinthoides hispanica), and Saruma henryi (upright wild ginger, an endangered plant from China).

Pests/Problems: There were no serious plant pests noted this week. Drought stress is likely to be problematic in the coming weeks without a substantial increase in precipitation.
 

Pioneer Valley Region (Easthampton)

General Conditions: While summer has only unofficially started with the passing of Memorial Day weekend, rising temperatures and increasing humidity are making the transition feel official. With the first half of May being so abnormally cool, the above-average temperatures in the region are feeling very warm right now. Sunny and dry best characterizes this past reporting period throughout the tri-counties. We experienced nearly cloudless skies from 5/19–5/22 & 5/24 and plant development has accelerated dramatically. High temperatures this past week have ranged from 72–87°F with low temperatures ranging from 37–63°F. A mixture of morning fog and clouds blanketed the valley bottom for much of the morning on 5/26 and 5/27. This warm stretch and cloud cover will last into the weekend (5/30–31) when temperatures will moderate back to seasonal norms. While rain is forecast for 5/29 and 5/30, expected totals are minimal at best. Measurable precipitation has been scant this month since the soaking rain that occurred on 4/30–5/1 and soils are really drying out in full sun settings, so begin a regular watering regimen for plants in need of supplemental irrigation if you haven’t already. Watering that avoids wetting the canopy of trees and shrubs will provide more water where it’s needed and avoid stimulating common pathogens. While dry weather can lead to drought stress, it also reduces the window of time pathogens can utilize for infection and spread. By wetting the foliage and young shoots with overhead sprinklers, free moisture is provided, stimulating pathogen activity. The heat will unfortunately hasten the flowering of certain plants in bloom now, like Mariesii Viburnum and Scintillation Rhododendron, among others. But, the mild winter and cool temperatures in April and early May resulted in a fantastic spring for flowering trees and shrubs, with some blooming for what seems like twice the normal period. Red maple samaras are mature and swirling to the ground. Oaks are mostly done flowering and the spent catkins are dropping everywhere, accumulating in large piles along the side of the road. Hemlocks flushing new growth look amazing with their lime green tips of new growth contrasting against the dark green needles of old. Pollen remains heavy in the air right now and we could use a good storm to wash everything off.

Pests/Problems: Mosquitoes have really increased in both abundance and annoyance over the past week, swarming even during the mid-day hours under partial shade. Ticks also continue to be a problem in certain pockets of the Pioneer Valley. Because of the mast year for red oaks in 2019, rodent populations are expected to increase this year, leading to a corresponding increase in tick populations in 2021. Needle browning on eastern white pine is increasing in severity on scattered trees around the area. Browning and shedding of older needles, due to white pine needle blight, is usually at its peak in early June. This corresponds with peak spore dispersal and infection of the current year’s needles by the various pathogens responsible. Minor levels of caterpillar feeding can be found on a variety of trees and shrubs at this time, although the culprit is often hiding when the damage is observed. Early instar forest tent caterpillars have been spotted. Frog eye leaf spot, caused by Botryosphaeria obtusa, was observed on espalier apple (Malus domestica). In addition to leaf spotting, B. obtusa can cause a fruit rot and stem/branch canker (known as black rot), making it a formidable pathogen when left unchecked. Leaf galls, mites and aphids are starting to become more conspicuous. Anthracnose on oak, maple and elm is still difficult to find, based on limited scouting. While unsightly, they usually cause little to no injury to plants. Larvae of Calyptra canadensis (Meadow Rue Owlet moth) were found feeding on numerous plantings of meadow rue (Thalictrum rochebruneanum) at a scouting location (see photos). 

Berkshire Region (Great Barrington)

General Conditions: It seems that summer has arrived, at least temporarily. High temperatures of 85˚F at Pittsfield Airport and 86˚F in Richmond were recorded on the 26^th, a significant increase from the lows of 37˚F (Pittsfield), 36˚F (West Stockbridge) and 33˚F (Richmond) on the morning of May 21. However, a cool down appears in the forecast at the end of this week with a projected low of 40˚F in West Stockbridge on the mornings of May 31 and June 1. Besides the dramatic fluctuations in temperature, the primary weather factor is the lack of rainfall. As of May 26, the total precipitation for the year is 3.23 inches below normal. Still, soil moisture below the one-inch topsoil level is adequate to support plant growth. It certainly has not yet abated the rapid growth of turfgrass. Conditions are still good for seeding, planting and transplanting.

Pests/Problems: Pests observed this week include: boxwood leafminer (mostly in the pupal stage but with some larvae still active), lily leaf beetle adults, imported willow leaf beetle adults, spruce spider mites, and woolly beech aphid. Aphids have also been found on birch leaves. A very heavy infestation of boxwood psyllids was observed at one scouting site. Apple scab continues to develop on crabapples with some leaf drop noted. Black spot has appeared on roses. A little frost injury from earlier this month could still be seen on the earliest emerging leaves of peonies and red chestnut. A contact in Lanesboro reported some earlier frost damage on ostrich ferns and on shoots of yellow bells (Kirengeshoma koreana). In all cases, later emerging foliage was fine. Carpenter bees, wasps, mosquitoes, and gnats are annoying. Adult deer ticks continue to be found in large numbers. This scout received his 4^th tick bite of the spring this past week. While COVID-19 is on the minds of most people, one should not overlook or disregard protecting themselves from deer ticks.

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, temporarily reporting from Easthampton.
• BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

The UMass Plant Diagnostic Lab remains closed at this time. Plans for reopening are slowly progressing and there is hope we can resume diagnosing plant samples soon. When a specific date is confirmed, we will share this information widely.

Scout for symptoms of maple anthracnose, caused by several different fungal pathogens in our region. Despite the dry weather, infections may appear on landscape trees, especially those in deep shade. On large, mature trees that are otherwise healthy, anthracnose is of minor concern. However, for young and recently transplanted trees, it can be an important stress. On Japanese maples, the lesions may appear water-soaked or translucent, turning pale brown over time. Leaves may then shrivel and crinkle before wilting as they die. Continue to prune dead stems from Japanese maple can

Populations of boxwood leafminer are locally high this season. Damage from these infestations can lead to additional problems, namely Volutella blight. Unfortunately, boxwood harbors one of the largest assemblages of destructive insect pests and pathogens. Careful scouting for boxwood blight continues to be a top priority, especially when numerous plants are present on a property. Recognizing the difference in symptoms between the various ailments is critical for proper boxwood care. To that end, a compilation fact sheet was created outlining common health issues for boxwood. This will be expanded with photos and additional information over time since boxwood problems only seem to be increasing!

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

Insects

A New Opportunity for Online Learning about Invasive Insects!

Join UMass Extension’s Landscape, Nursery, and Urban Forestry Program and UMass Extension’s Fruit Program for an exciting FREE series of seven webinars focusing on the impact, monitoring, and management of invasive insects in Massachusetts and the nation! Topics include the spotted lanternfly, spotted wing drosophila, brown marmorated stink bug, emerald ash borer, gypsy moth, Asian longhorned beetle, and more! Webinars will be held from Noon-1:00 PM on May 21, May 28, June 4, June 9, June 16, June 23, and June 30, 2020. Each webinar in this series offers 1 pesticide credit (categories 29, 35, 36, and applicators (core)) and MCA/MCLP’s earn 0.5 education credits for each webinar. ISA and SAF credits are available.

The third webinar in this series will happen LIVE on:

Thursday, June 4, 2020

Spotted Lanternfly and Environmental DNA: Insect Monitoring of the Future

Dr. Julie Lockwood, Professor and Chair, Ecology, Evolution and Natural Resources, Rutgers University

The increased numbers of invasive insects, and the huge toll they can exact, argues strongly for better tools for pest species monitoring and surveillance. Once such tool relies on capturing the DNA shed by invasive insects as they move through their habitats, called environmental DNA (eDNA). Much like using DNA evidence in a criminal trial, invasive insect eDNA monitoring tools allow us to pinpoint where these species have been without ever having to catch them ‘in the act’. I’ll show how eDNA is a vast improvement over conventional methods in our ability to detect and monitor spotted lanternfly in forests, urban areas, and vineyards.

Don’t miss this excellent opportunity! For more information about all of the webinars in this series, to register, and to see archived recordings for any that you missed, visit: https://ag.umass.edu/landscape/education-events/invasive-insect-webinars

Insects and Other Arthropods of Public Health Concern:

• Deer Tick/Blacklegged Tick: Check out the archived FREE TickTalk with TickReport webinars available here: https://ag.umass.edu/landscape/education-events/webinars . Previous webinars including information about deer ticks and associated diseases, ticks and personal protection, and updates from the Laboratory of Medical Zoology are archived at the link above.

The next live webinar will be held on June 10, 2020: Tick Management and Control. Dr. Stephen Rich (Professor of Microbiology and Director of the UMass Laboratory of Medical Zoology) and Dr. Kirby Stafford (Chief Scientist at the Connecticut Agricultural Experiment Station and CT State Entomologist) will discuss tick management strategies applicable to landscapes in the Northeast. Dr. Stafford is a medical veterinary entomologist whose research expertise is on the ecology and control of ticks, especially the black-legged or deer tick (Ixodes scapularis) that transmits several pathogens, including those that cause Lyme disease, human babesiosis, and human ehrlichiosis.

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. Deer tick nymphs (immatures) are also active, and may be encountered at this time, through August. Nymphs will have already taken a blood meal, and therefore can be infected with disease causing pathogens. It is important to protect yourself against ticks and be especially vigilant for tiny, difficult to see nymphs. 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 .

Have you just removed an attached tick from yourself or a loved one with a pair of tweezers? If so, consider sending the tick to the UMass Laboratory of Medical Zoology to be tested for disease causing pathogens. To submit a tick to be tested, visit: https://www.tickreport.com/ and click on the blue “Order a TickReport” button. Results are typically available within 3 business days, or less. By the time you make an appointment with your physician following the tick attachment, you may have the results back from TickReport to bring to your physician to aid in a conversation about risk.

The UMass Laboratory of Medical Zoology does not give medical advice, nor are the results of their tests diagnostic of human disease. Transmission of a pathogen from the tick to you is dependent upon how long the tick had been feeding, and each pathogen has its own transmission time. TickReport is an excellent measure of exposure risk for the tick (or ticks) that you send in to be tested. Feel free to print out and share your TickReport with your healthcare provider.

• 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).

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

There are ways to protect yourself against mosquitoes, including wearing long-sleeved shirts and long pants, keeping mosquitoes outside by using tight-fitting window and door screens, and using insect repellents as directed. Products containing the active ingredients DEET, permethrin, IR3535, picaridin, and oil of lemon eucalyptus provide protection against mosquitoes.

For more information about mosquito repellents, visit: https://www.mass.gov/service-details/mosquito-repellents and https://www.cdc.gov/features/stopmosquitoes 

• Wasps/Hornets: Many are noticing the spring time “awakening” of various species of wasps/hornets in Massachusetts at this time. Many wasps are predators of other arthropods, including pest insects such as certain caterpillars that feed on trees and shrubs. Adult wasps hunt prey and bring it back to their nest where young are being reared, as food for the immature wasps. A common such example are the paper wasps (Polistes spp.) who rear their young on chewed up insects. They may be seen searching plants for caterpillars and other soft-bodied larvae to feed their young. Paper wasps can sting, and will defend their nests, which are open-celled paper nests that are not covered with a papery “envelope”. These open-celled nests may be seen hanging from eaves or other outdoor building structures. Aerial yellow jackets and hornets create large aerial nests that are covered with a papery shell or “envelope”. Common yellow jacket species include those in the genus Vespula. Dolichovespula maculata is commonly known as the baldfaced hornet, although it is not a true hornet. The European hornet (Vespa crabro) is three times the size of a yellow jacket and may be confused for the Asian giant hornet (Vespa mandarinia). The European hornet is known to Massachusetts, but the Asian giant hornet is not. If you are concerned that you have found or photographed an Asian giant hornet, please report it here: https://massnrc.org/pests/report.aspx . Paper wasps and aerial yellowjackets overwinter as fertilized females (queens) and a single female produces a new nest annually in the late spring. Nests are abandoned at the end of the season. It is this annual behavior of queens starting new nests, laying eggs, and rearing new wasps to assist in colony/nest development that may lead people to believe that wasp/yellow jacket numbers are high at this time of year. While populations may fluctuate and insect survival may have been aided by a mild winter (although that is not always true for all species), it is difficult to tell if these insects are more numerous this year, or just that they are more noticeable now that nest construction and brood development are under way for the season. Either way, 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 their nests, and if that cannot be done and assistance is needed to remove them, consult a professional.

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

• 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.
• Arborvitae Leafminer: In New England and eastern Canada, four species of leafminers are known to infest arborvitae. These include Argyresthia thuiella, A. freyella, A. aureoargentella, and Coleotechnites thujaella. The arborvitae leafminer, A. thuiella, is the most abundant of these and has the greatest known range when compared to the others. (It is also found in the Mid-Atlantic States and as far west as Missouri). Moths of this species appear from mid-June to mid-July and lay their eggs. The damage caused by all of these species is nearly identical. Trees, however, have been reported to lose up to 80% of their foliage due to arborvitae leafminer and still survive. At least 27 species of parasites have been reported as natural enemies of arborvitae leafminers, the most significant of which may be a parasitic wasp (Pentacnemus bucculatricis). Arborvitae leafminer damage causes the tips of shoots and foliage to turn yellow and brown. If infestations are light, prune out infested tips.
• Azalea Sawflies: There are a few species of sawflies that impact azaleas. Johnson and Lyon's Insects that Feed on Trees and Shrubs mentions three of them. Amauronematus azaleae was first reported in New Hampshire in 1895 and is likely found in most of New England. Adults of this species are black with some white markings and wasp-like. Generally green larvae feed mostly on mollis hybrid azaleas. Remember, sawfly caterpillars have at least enough abdominal prolegs to spell “sawfly” (so 6 or more prolegs). Adults are present in May, and females lay their eggs and then larvae hatch and feed through the end of June. There is one generation per year. Nematus lipovskyi has been reared from swamp azalea (Rhododendron viscosum). Adults of that species have been collected in April (in states to the south) and May (in New England) and larval feeding is predominantly in late April and May in Virginia and June in New England. One generation of this species occurs per year, and most mollis hybrid azaleas can be impacted. A third species, Arge clavicornis, is found as an adult in July and lays its eggs in leaf edges in rows. Larvae are present in August and September. Remember, Bacillus thuringiensis Kurstaki does not manage sawflies.
• Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs. 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. Remove and destroy overwintering bags before June. In certain areas across MA in 2019, increased populations of bagworms were observed and reported. More information can be found here: https://ag.umass.edu/landscape/fact-sheets/bagworm
• 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 ‘Winter Gem’ 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.
• 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 were 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 (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.
• 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). Eastern tent caterpillars were seen creating webbing and feeding in Chesterfield, MA on 5/19/2020 and again on 5/26/2020. 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. 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.
• Emerald Ash Borer: (Agrilus planipennis, EAB) Since the New Year, the Massachusetts Department of Conservation and Recreation has confirmed at least 18 new community detections of emerald ash borer in Massachusetts. While the cities and towns with recent detections of EAB are too numerous to list here, they are in areas of Essex, Franklin, Hampshire, Middlesex, Norfolk, and Worcester counties. It is worthwhile to note that this was the first detection of EAB in Franklin County. 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. Positive identification of an EAB-infested tree may not be possible with these signs individually on their own.

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

• Eriophyid Mites: these insect relatives are known to create different types of leaf galls on certain host plants. The crimson erineum mite or Eriophyes elongates is one of my favorites. This insect can be found on the leaves of sugar maple, creating felt patches on the upper leaf surface that appear pink, or a deep crimson red. The crimson erineum mite was seen on sugar maple in Chesterfield, MA on 5/28/2020. Like the vast majority of leaf galls, the crimson erineum mite does not cause significant injury to its host plant, and therefore management is not necessary.

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.
• 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 2020. However, that does not mean the occasional egg mass won’t be seen in certain areas of the state. Egg hatch was observed and reported with photo evidence in Shelburne Falls, MA on 5/4/2020. Shadbush (Amelanchier spp.) was reported as in full bloom at the same time in that area.

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.)

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

• 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.
• Holly Leafminers: Seven species of leaf miners feed on holly. Phytomyza ilicicola is usually referred to as the native holly leafminer. This species is known to feed on Ilex opaca, I. crenata, and related cultivars; however, it only lays its eggs in American holly (Ilex opaca). Some research suggests that the native holly leafminer may lay its eggs in other Ilex species, but that the larvae are unable to complete their development. This insect is found throughout the native range of its host plants. Larvae overwinter in leaf mines and pupation occurs in March and April and adult emergence by mid-May (192-298 GDD’s, base 50°F). Adult flies are known to emerge over a period of 6 or so weeks in the spring. Females lay eggs using their ovipositor on the underside of newly formed leaves. A tiny green blister forms on the leaf as the first symptom of injury. Larvae hatch from the egg and create a narrow mine that may appear brown from the upper leaf surface. Mines are broadened in the fall and a large blotch is completed in the winter. Larvae are yellow maggots and reach 1.5 mm. in length when mature. Current year’s mines are easily overlooked due to the slow feeding patterns of the larvae. Premature leaf drop may occur. Remove and destroy mined leaves before May. Phytomyza ilicis is usually only referred to as the holly leafminer, and it is a non-native species introduced from Europe and only feeds on Ilex aquifolium. (The native holly leaf miner does not develop in I. aquifolium.) The biology and damage this insect causes is similar to that of the native holly leafminer, with the exception of the fact that eggs are laid in the midvein of the leaf and young larvae tunnel in the vein until the fall. Remove and destroy mined leaves before May. Adults may be present mid-late May (246-448 GDD’s, base 50°F).
• 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 bugs 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. Imported willow leaf beetle adults were observed feeding and mating in Chesterfield, MA on 5/20/2020. Adults continue to feed and mate on 5/26/2020 and egg laying has been observed. 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.
• Lacebugs: Stephanitis spp. lacebugs such as S. pyriodes can cause severe injury to azalea foliage. S. rhododendri can be common on Rhododendron and mountain laurel. S. takeyai has been found developing on Japanese Andromeda, Leucothoe, Styrax, and willow. Stephanitis spp.lace bug activity should be monitored through September. Before populations become too large, treat with a summer rate horticultural oil spray as needed. Be sure to target the undersides of the foliage in order to get proper coverage of the insects. Certain azalea and Andromeda cultivars may be less preferred by lace bugs.
• 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 this time. For more information about this insect, visit the newly updated fact sheet: https://ag.umass.edu/landscape/fact-sheets/lily-leaf-beetle .

Want to learn more about lily leaf beetle’s life cycle and learn to recognize adults, larvae, and eggs? Take 3 minutes to watch Episode 2 of InsectXaminer, here: 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.
• Rhododendron Borer: Synanthedon rhododendri is one of the smallest of the native clearwing moths. Rhododendrons are preferred hosts, although mountain laurel, and deciduous azaleas can be heavily infested, especially if they are planted in close proximity to rhododendrons. Injury may be first noticed in the fall (leaves lose their sheen, then become pale green, then olive, then chlorotic) and can look similar to drought stress. On branches that seem to be stunted, look at limb crotches, scars, and other irregularities for sawdust stuck on bark or on the ground beneath these areas. In late May and early June, holes may contain pupal shed skins extending halfway out. Moth emergence occurs in the late-spring, early-summer. After mating, female moths seek out suitable egg laying locations (preferring wounded areas or limb crotches). The female lays her eggs and dies. Eggs hatch and larvae tunnel into the inner bark where they feed in tunnels that become packed with reddish frass pellets. By late fall, larvae move to the sapwood where they overwinter and resume feeding by mid-March. Pupation occurs in the spring and there is one generation per year. Prune out and destroy infested branches before late May/June. Monitor for adults in mid-May (192-298 GDD’s, base 50°F).
• Roseslugs: Two species of sawfly can be found on the leaves of roses at this time. These small, caterpillar-like larvae will skeletonize the upper leaf surface and leave a “window-pane” like pattern behind. When present in large numbers, these insects are capable of defoliating their entire host. Management options include an insecticidal soap spray or a product containing spinosad.
• 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.
• Spotted Lanternfly: (Lycorma delicatula, SLF) is not known to occur in Massachusetts landscapes (no established populations are known in MA 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

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/ This map depicts an individual find of spotted lanternfly at a private residence in Boston, MA that was reported by the MA Department of Agricultural Resources on February 21, 2019. More information about this detection in Boston, where no established infestation was found, is provided here: https://www.mass.gov/news/state-agricultural-officials-urge-residents-to-check-plants-for-spotted-lanternfly

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.

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 from over 70 species of plants, including 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 .

• 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. 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.
• Taxus Mealybug: Dysmicoccus wistariae will produce honeydew and lead to sooty mold growth, yellowing of needles, and sparsely foliated plants. Eventual dieback may be possible. This species is commonly associated with taxus in New England, but can be occasionally found on dogwood, rhododendron, Prunus spp., maple, Andromeda, and crabapple. These mealybugs are found on stems and branches and particularly like to congregate at branch crotches. Taxus mealybug feeds in the inner bark tissue of the trunk and branches. Adult females are present from June to August and give birth to living young in the summer. Immatures overwinter. A single generation may occur per year in New England, but areas to the south can have multiple generations of this insect. Management may be targeted between 246-618 GDD’s, base 50°F. Horticultural oil and neem oil may be used.
• Twolined Chestnut Borer: Agrilus bilineatus is a native jewel beetle (also known as a flatheaded borer) in the Family Buprestidae. This insect is also in the same genus as the invasive emerald ash borer. The twolined chestnut borer is native to Massachusetts, much of New England, and the eastern United States. This species has one generation per year and adults are typically active from April – August, depending upon location and temperature. Adults will conduct some maturation feeding on oak prior to mating. Females will lay clusters of tiny eggs in the cracks and crevices of bark. Larvae hatch from the eggs in 1-2 weeks and burrow through the bark into the cambium, where they feed in a similar manner to the emerald ash borer, creating meandering galleries as they feed. (The galleries of the twolined chestnut borer can be straight in very stressed trees.) Larvae typically mature by August – October and burrow to the outer bark where they create a chamber in which they overwinter. Pupation occurs the following spring and adults emerge through D-shaped exit holes that are approximately 1/5 inch wide. In the northern extent of this insect’s range, they can take 2 years to complete their life cycle. Larvae of this insect have been recorded from eastern white oak, common post oak, burr oak, scarlet oak, northern red oak, and eastern black oak. Adults have been recorded on fir and pin oak. These insects are attracted to stressed host plants and typically become a secondary factor in the decline of the tree.
• 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. 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 leaf litter 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.
• 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 likely will 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.

In landscape settings in eastern Massachusetts, it is best to wait until the leaves of susceptible hosts completely unfold and monitor for feeding caterpillars, prior to treatment, especially since populations in Massachusetts continue to be so low in many locations. Be sure that management of this insect is necessary by monitoring for damaging populations before making applications in landscape settings. For more information about the life cycle and management of winter moth, please visit thisfact sheet: Winter Moth Identification and Management ( https://ag.umass.edu/landscape/fact-sheets/winter-moth-identification-management ).

Winter moth is a non-native insect that was identified in Massachusetts for the first time in 2003 following persistent reports of defoliation in eastern areas of the state such as Cape Anne and on the North Shore near Cohasset, Hingham, and Rockland on the South Shore in the late 1990’s. For more detailed information about the history of this insect pest in North America and Massachusetts, please visit this fact sheet: Winter Moth in Massachusetts: History and Biological Control ( https://ag.umass.edu/landscape/fact-sheets/winter-moth-in-massachusetts-history-biological-control ).

• 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 .

A note about Tick Awareness: deer ticks (Ixodes scapularis), the American dog tick (Dermacentor variabilis), and the lone star tick (Amblyomma americanum) are all found throughout Massachusetts. Each can carry their own complement of diseases. Anyone working in tick habitats (wood-line areas, forested areas, and landscaped areas with ground cover) should check themselves regularly for ticks while practicing preventative measures. Have a tick and need it tested? Visit the web page of the UMass Laboratory of Medical Zoology (https://www.tickreport.com/ ) and click on the blue Order a TickReport button for more information.

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

Weeds

Do not delay, treat garlic mustard, Alliaria petiolata, now. Plants are in full flower or approaching full flower with seedpods forming with seeds that are not yet mature. Applications at this time of year will control second year plants before they go to seed as well as first year seedlings.

Tree seedlings are continuing to germinate and some locations may have seedlings that are 2 to 3 inches tall. These seedlings can be treated with pelargonic acid (Scythe^TM). Another option would be to cut these seedlings with a gas powered, electric or battery powered hedge shear at the soil or mulch surface. The organic/non-chemical products do not translocate and so will not provide effective control of these young tree seedlings. Tree seedlings in turf areas will be controlled with mowing, so an herbicide application is not necessary.

New growth expansion of poison ivy continues. It’s still a little early to treat so wait until the end of flowering - any time from late June to mid-September.

Do not attempt to control Japanese knotweed, Polygonum cuspidatum, at this time as herbicide applications are not effective. In preparation for a late season herbicide application, cut or mow stands of knotweed to the ground in late May and early June. This practice is done to facilitate herbicide application by removing the dried stems from the previous year’s growth and will control plant height so knotweed will be shorter at the time of treatment in late summer. There is also some indication that the plant’s carbohydrate reserves may be reduced with this early season mowing.

Report by Randy Prostak, Weed Specialist, UMass Extension Landscape, Nursery and Urban Forestry Program

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Diagnostic Services

A 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 Plant Diagnostics Laboratory . No samples are being accepted at this time.

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Ticks are active any time that temperatures are above freezing! Remember to take appropriate precautions when working and playing outdoors, and conduct daily tick checks. UMass tests ticks for the presence of Lyme disease and other disease pathogens. Learn more