Landscape Message: May 15, 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 13, 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	3.5	51	51	47	0.74	12:00 PM 5/13
SOUTHEAST	0.5	63.5	69	48	0.60	3:30 PM 5/13
NORTH SHORE	1.5	79	52	42	0.79	3:30 PM 5/13
EAST	5	101.5	50	47	0.76	6:30 AM 5/14
METRO	3.5	70	46	44	0.65	6:00 AM 5/13
CENTRAL	0.5	70	41	40	0.41	7:15 AM, 5/13
PIONEER VALLEY	0	57	62	46	0.34	5:00 PM 5/13
BERKSHIRES	0	40.5	41	39	0.50	7:15 AM 5/13
AVERAGE	2	67	52	44	0.60	-
n/a = information not available

Phenology

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT	CAPE	SE	NS	EAST	METRO	CENT	PV	BERK
Syringa vulgaris (common lilac)	Begin	Begin	*	Begin	Begin	Begin	Begin/Full	*
Rhododendron spp. (early azaleas)	Begin	Begin/Full	Begin/Full	Begin	Begin	Begin	Begin/Full	Begin
Cercis canadensis (redbud)	*	Full	Begin	Begin/Full	Full	Begin/Full	Full	Begin
Cornus florida (flowering dogwood)	Begin	Full	Full	Begin/Full	Begin/Full	Begin	Full	Begin
Malus spp. (crabapple)	Full	Full/End	Full	Full/End	Full/End	Full	Full	Begin
Amelanchier spp. (shadbush, serviceberry)	Full/End	End	End	End	End	End	End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature for the period from May 6 to May 13 was 48˚F with a high of 60˚F on May 7 and a low of 36˚F on May 10. The weather related excitement for the period were the snow flurries and near freezing temperatures over the weekend. Overall, the week has seen highs in the 50s with lows in the 40s and partly cloudy days. Less than an inch of precipitation fell during the period spread out amongst three minor rain events. Topsoil and subsoil moisture remain adequate.

Pests/Problems: Pests to keep an eye out for include Lecanium scale on woody ornamentals. High populations of Lecanium scale are still widespread across the Cape. Look for the small (1-1.5mm) reddish brown oval scales on last year’s woody growth. The presence of whitish scale indicates bio control at work, likely an entomopathogenic fungi. The presence of sooty mold is a good indicator of Lecanium scale. Many evergreens such as Rhododendron still have a covering of sooty mold from the fall. Winter moth caterpillars can be found causing minor (insignificant) damage to some plants like rose and Japanese maple. Winter moth is no longer considered a plant health risk for our area and therefore chemical intervention is not warranted. Unusually large populations of March Flies (Bibionidae) have been seen. Other insects or insect damage observed during the period include bark beetle on eastern red cedar, boxwood leafminer damage on boxwood, Hydrangea leaftier damage on smooth Hydrangea and red lily leaf beetle adults on lily. Disease and disease symptoms seen over the period include shothole disease on skip laurel - an interesting disease with potentially many causes including fungi, bacteria, and cultural conditions. Symptoms look like insect damage to leaves. Telial horns for cedar apple rust were active over the weekend, black spot on rose, leaf spots on azalea, and tulip fire (a fungal disease caused by Botrytis tulipae) which produces brown spots and twisted, withered and distorted leaves on tulip. Weeds seen in bloom during the period include speedwell (Veronica spp), purple deadnettle (Lamium purpureum), yellow rocket (Barbarea vulgaris), dandelion (Taraxacum officinale), common violet (Viola papilionacea), mouse ear chickweed (Cerastium vulgatum) and garlic mustard (Alliaria petiolata). Rabbits are mowing down perennials. Black legged tick nymphs have emerged. Make sure to keep yourself protected while working outdoors.

Southeast Region (Dighton)

General Conditions: A polar vortex brought snow showers, frost warnings and thunderstorms interspersed with a few glorious days from 5/6 through 5/13. The weather seemed more typical of early April than May. Lawns are greening up nicely and finally evening out over the areas where the dog has been visiting. The following plants are in flower: Cornus florida, Cercis canadensis, Rhododendron vaseyi (pinkshell azalea), Syringa vulgaris, Malus spp, Viburnum carlisii (Koreanspice Viburnum), Prunus spp, P. serrulata "Kwanzan", P. maritima, P. japonica, Allium spp, Lunaria annua, Aquilegia spp, late tulips, Hyacinthoides hispanica (Spanish bluebell), Trillium grandiflorum, T. sessile, Vinca minor, Phlox subulata, Viola spp, Arisaema triphyllum, Lamprocapnos spectabilis, Orinthogalum umbelatum, Pulmonaria spp., and Geranium maculatum.

Pests/Problems: Wild weather hasn't kept the weeds at bay; dandelion, red sorrel, buckhorn plantain (Plantago lanceolate), garlic mustard, greater celandine (Chelidonium majus), Poa annua, and ground ivy are flowering. Poison ivy leaves are red and easily observed in contrast with other foliage. Japanese knotweed shoots have already achieved three feet in height. It seems we're having a bumper crop of Norway maple seedlings this year. Mosquitoes are beginning to be a problem as are ticks.

North Shore (Beverly)

General Conditions: The weather during this reporting period was the typical spring weather expected this time of the year. However, the temperatures were below average. The low temperatures have slowed down gardening activities but spring cleanup continued during the week. Due to the cool temperatures, the bloom period of many plants is lasting longer and is brilliant. During this week approximately 0.79 inches of rain were received at Long Hill. The soils are moist, lawns are green and turf is thriving. Weeds are also thriving. Woody plants seen in bloom during this reporting period include: flowering dogwood (Cornus florida), redbud (Cercis canadensis), large Fothergilla (Fothergilla major), royal azalea (Rhododendron schlippenbachii), hardy orange (Poncirus trifoliata), crabapple (Malus spp.), apple (Malus spp.) and highbush blueberry (Vaccinium corymbosum). Non-woody plants seen in bloom include: Trillium (Trillium spp.), bleeding heart (Lamprocapnos spectabilis), dollar plant (Lunaria annua), forget me not (Myosotis scorpioides), trout lily (Erythronium americanum) and barrenwort (Epimedium spp.).

Pests/Problems: Invasive weeds garlic mustard (Alliaria petiolata) and lesser celandine (Ranunculus ficaria) are in full bloom. Other problematic weeds in bloom include dandelion (Taraxacum officinale) and violets (Viola spp.). No insect pest activity was reported, but ticks are very active. Protect yourself with repellent when working outdoors.

East Region (Boston)

General Conditions: We have experienced below average temperatures for the period from May 6 to May 13. Daytime highs ranged from 45.3°F to 66.2°F, averaging 58.3°F, while lows ranged from 33.4°F to 41.9°F, averaging 37.6°F. On the morning of May 9, the temperature dipped down to 33°F as we had non-accumulating snow followed by a daytime high of only 45.3°F. The temperature in Boston was 37°F on the morning of May 13, breaking a record for the coldest temperature on that day since 1882. It has been unseasonably cold and windy to say the least. We accumulated only 5.0 GDDs over the last week. Turf continues to green up and many plants are blooming throughout the landscape. Ladybird beetles are actively feeding on aphids. Dipelta floribunda (rosy Dipelta, a non-native shrub) is in bloom.

Pests/Problems: The unusually cold conditions over the past week has been the topic of conversation. We experienced several light frosts resulting in minor damage to exposed tender foliage of early azaleas, Hosta and roses. Fungal pathogens continue to thrive in the moist overcast conditions. Unmanaged garlic mustard is in full bloom. Cynanchum spp. (of which “dog strangle”, black swallow wort are examples) are just beginning to emerge in warm and sheltered areas. Star of Bethlehem is becoming a problematic invader of perennial beds and turf. Berberis spp. are in full bloom. Hydrangea Leaf Tier (Olethreutes ferriferana) is actively forming enclosures over the buds of Hydrangea and feeding on the leaves and flower bud inside.

Metro West (Acton)

General Conditions: We experienced typical New England spring-like temperatures during this last week’s reporting period. It was cold, warm, windy and wet on any given day. There was a snow flurry on the 9^th, a hailstorm on the 12^th and wind gusts of up to 25 mph on the 9^th. The highest temperature recorded for this week was 69°F on the 11^tth and the lowest temperature recorded was 28°F on the 10^th. The average monthly rainfall for May is 4.04” and as of the 12^th I have recorded 1.41”. As with any spring, the landscape is exploding with color! Observed in some stage of bloom this past week were the following woody plants: Amelanchier spp. (shadbush, serviceberry), Cercis canadensis (redbud), Cercis canadensis “Alba” (white flowering redbud), Chaenomeles speciosa (common flowering quince), Cornus florida (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), Kerria japonica (Japanese Kerria), Magnolia soulangeana (saucer Magnolia), Magnolia x loebneri 'Merrill' (Merrill Magnolia), Malus spp. (apple, crabapple), Prunus spp. (cherry), including Prunus serrulata 'Kwanzan' (Japanese flowering cherry), and P. japonica (flowering almond), Pyrus spp. (pear), Rhododendron spp. [early flowering Rhododendron/Azalea - including R. vaseyi (pink shell azalea)], Spiraea spp. (bridal wreath), Syringa spp. (early blooming lilac), Syringa vulgaris (common lilac), Vaccinium angustifolium (lowbush blueberry), V. corymbosum (highbush blueberry), Viburnum carlesii (Koreanspice Viburnum), V. x burkwoodii (Burkwood Viburnum) and V. x burkwoodii 'Mohawk' (Mohawk Burkwood Viburnum).

Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Anemone nemorosa (wood anemone), Aquilegia canadensis (columbine), Arisaema triphyllum (Jack-in-the-pulpit), Asarum canadense (Canandian ginger), A. europaeum (European ginger), Aurinia saxatilis (basket of gold), Caltha palustris (marsh marigold), Claytonia virginica (Virginia spring beauty), Dicentra canadensis (squirrel corn), D. cucullaria (dutchman's breeches), D. eximia (fringed bleeding heart), D. spectabilis (old fashioned bleeding heart), D. spectabilis ‘Alba’ (white old fashioned bleeding heart), Epimedium x versicolor 'Niveum' (white flowering barrenwort), E. x versicolor 'Roseum' (pink flowering barrenwort), E. versicolor 'Sulphureum' (yellow flowering barrenwort), Gallium odoratum (sweet woodruff), Helleborus niger (Christmas rose), Hyacinthus spp. (Hyacinth), Iris germanica (bearded Iris), Linaria annua (money plant), Mertensia virginica (Virginia bluebells), Myosotis sylvatica (forget-me-not), Narcissus spp. (daffodil), Nepeta spp. (ornamental catmint), Pachysandra terminalis (Japanese Pachysandra), Phlox subulata (moss Phlox), Primula spp. (primrose), Pulmonaria longifolia (lungwort), P. rubra (salmon colored lungwort), Sanguinaria canadensis 'Multiplex' (double bloodroot), Stylophorum diphyllum (wood poppy), Tiarella cordifolia (foam flower), Trillium erectum (red flowering trillium), T. grandiflorum (white flowering trillium), T. sessile (toadshade trillium), Tulipa spp. (tulip), Vinca minor (periwinkle), Viola spp. (violet), and Waldsteinia ternata (barren strawberry).

Pests/Problems: The heavy rain and strong winds shortened bloom times and forced early flower drop on some trees and shrubs while the cool temperatures have prolonged bloom time on others. Snowball Aphid and the distorted leaves it causes are evident on Viburnums. Ticks and black flies are feeding and active. Many weeds are in flower, including one of the most invasive of all time, Alliaria petiolata (garlic mustard). It’s just beginning to bloom and is easily seen - because of its white flowers - growing everywhere including roadsides, woodlands, wetlands and gardens. Berberis thunbergii (Japanese barberry), an invasive shrub that is harder to detect at this time of the year continues to bloom. Be aware of Toxicodendron radicans (poison ivy). It is beginning to leaf out, thus fairly easy to detect with its shiny, red young leaves of three.

Central Region (Boylston)

General Conditions: We’ve grown so accustomed to spring temperatures soaring into the 70’s and 80’s in May that this spring feels abnormally frigid. We experienced three nights of freezing temperatures during the past reporting period, frustrating the gardener who is eager to get going with annual and vegetable garden planting. Although the cold temperatures have slowed some gardening activities, they have made for a long, vibrant, colorful spring. Observed in bloom this week: Magnolia x soulangeana (saucer Magnolia), Potentilla canadensis (dwarf cinquefoil), Fothergilla gardenii (dwarf Fothergilla), Anemone coronaria ‘Lord Lieutenant’, Dicentra formosa (fernleaf bleeding heart), Dicentra cucullaria (Dutchman’s breeches), Aurinia saxatalis (basket of gold), Phlox divaricata (woodland Phlox), Malus (apples and crabapples), Hydrastis canadensis (goldenseal), and Trillium grandiflorum (white wakerobin). Also observed this week were two native orchids in bud that will flower in the coming weeks. Cypripedium acaule (pink lady’s slipper) and Isotria verticillata (large whorled pogonia). Although commonly considered quite rare, pink lady’s slippers are fairly common and widespread throughout Massachusetts. They prefer well-drained, dry acid soils and although they are common in the wild, their mycorrhizal dependence and limited root system makes them nearly impossible to cultivate or transplant. Large whorled pogonia is extremely rare in the wild across New England. Its flower is unusual, quite beautiful, but easy to miss if you aren’t looking for it. These are just two of the nearly two dozen members of the orchid family that are found in New England.

Pests/Problems: The cold temperatures, snow, hail, thunderstorms, and wind made for a wild weather week. Many common landscape weeds are quite active at this point in the season, including many invasive species such as Alliaria petiolata (garlic mustard), which is now in full bloom. Ticks are quite active. Otherwise, very few notable landscape problems were observed this week.

Pioneer Valley Region (Easthampton)

General Conditions: It was another week of cool and unsettled weather over this past reporting period as we settle into mid-May. High temperatures once again were stubbornly restrained below seasonal averages, reaching only the upper 50s to low 60s, while low temperatures dipped near or below freezing each night. There were localized pockets of frost in the valley with scattered freeze injury on tender annuals and perennials. The nadir of this cold start to May took place on Saturday, 5/9 when fierce northerly winds, snow flurries and high temperatures in the low 40s serenaded the Pioneer Valley. Sustained winds were >35 mph while gusts exceeded 50 mph at Westover AFB. Branch and whole tree failure occurred with damage reported to isolated homes across the tri-county region. Conditions improved on Mother’s Day, with high temperatures in the upper 50s but the winds were still lingering with gusts >30 mph. Two rain events occurred over the past week, on 5/7–5/8 (0.19ʺ) and 5/11 (0.13ʺ) but totaled less than 0.5ʺ. Despite the cool temperatures, surface soils in exposed settings have been drying due to the relentless winds. Keep a close eye on recent transplants and provide a light watering to replenish the uppermost soil layer. Overall, soil moisture remains good but soil temperatures are stuck in a rut with the cold nights. Both the cool air and soil temperatures have kept new shoot and leaf development progressing at a painfully slow rate. While it’s been unseasonably cold, the first half of May has been quite sunny. The long-term forecast shows we’re finally breaking out from underneath this cold grip and temperatures will consistently reach seasonal averages (and above) during the day and night. The landscape should respond quickly. After last season’s mast year for oaks, there are a large number of germinating acorns right now in the forest (see photo below). According to the USFS Silvics Manual, only about 1% of all acorns are even available to regenerate a new seedling, with most eaten by wildlife and insects. It can take more than 500 acorns to produce a single one-year-old red oak (Quercus rubra) seedling. Turfgrasses seem content with the current conditions, continuing to grow at a strong pace.

Pests/Problems: Early season leaf rollers are active right now. These very small, green-colored caterpillars close individual or small groups of developing leaves to feed. For small and recently transplanted trees, carefully scout the canopy for these pests. Oriental bittersweet is actively growing right now. Once your eye is attuned, even tiny seedlings can be spotted and removed. Hand weeding right now is the easiest method at this time of year to eradicate emerging plants but chemical control is often required for larger diameter vines that are resuming growth. Reports from the UMass Cold Springs Orchard show that apple scab pressure is very high right now. Thankfully, conditions have been much too cool for the fire blight bacterium, Erwinia amylovora, to actively spread and cause disease. However, the wet and cool temperatures have been beneficial for the Pseudomonas syringae, which causes bud blast, shoot blight and branch/trunk cankers on Prunus species. Overall, insect and disease activity remains low due to the cold temperatures. The warming trend forecasted could rapidly change that dynamic, however, as mild temperatures will finally allow many fungal spores to germinate and invade tender host tissues. These fungi include anthracnose, shoot blight and stem cankering pathogens. This is why it’s critical to prune out as much dead material as possible from the canopy and remove nearby inoculum before the start of the season. A reduction in the initial inoculum may help to reduce the primary infection that starts the disease cycle. Rabbits and moles are very active right now. An important point to remember is that moles feed primarily on earthworms and soil insects and do not eat plants. Meadow voles, meanwhile, primarily eat plants, feeding on roots and bark from a variety of landscape plants. While meadow voles are most abundant in open, grassy fields with limited tree and shrub cover, they can be found in forested habitats. The two are easy to distinguish if you can manage to locate them; see photo below of the eastern mole (Scalopus aquaticus), photographed this past reporting period. Mulch fungi, in all their strange glory, are actively growing right now. It helps to know some of the more common types to calm nervous clients worried about an impending garden plague. Pictured below is Peziza, a cup fungus common in fresh bark mulch.

Berkshire Region (Great Barrington)

General Conditions: The only way to describe the weather of the past week, especially from May 9 through May 13, was unseasonably brutal. May 9 began with a one-inch snowfall, a heavy wet snow topped by a layer of graupel (snow pellets). Flurries continued on and off throughout the day. The 6AM temperature was 28˚ F at this site and wind speeds averaged 20mph with gusts at 40 mph or higher. It felt more like January 9 than May 9. Morning low temperatures continued to be at or below freezing. The May 13 low temperature was 26˚F at 6AM. The most uncomfortable feature of the stretch from May 9 – May 12 was persistent winds with frequent strong gusts. Fortunately, it appears that this unseasonably cold trend will end and more seasonable temperatures will occur, starting on May 14. The persistent winds did dry the surface layer of soils but soils are moist just an inch or less below the surface. Plant growth has been slow through the month thus far but the flowering period for most spring bulbs and early spring flowering trees, shrubs, and herbaceous perennials has been extended. One aspect of the environment seemingly unaffected through this cold period is turfgrass. It is lush, growing vigorously, and its deep green color stands out in a still otherwise mostly gray and brown landscape.

Pests/Problems: Pest problems remain minimal. The gnats and mosquitoes which were active just a week ago were not to be seen during this recent cold snap. Surely that will change with the impending change in weather conditions. The weather did not affect the tick population as occurrences of the ticks attaching themselves to their human hosts remained high. Many boxwood leafminers are now in their pupal stage. The shoots and foliage of emerging herbaceous perennials have provided fodder for browsing critters, mostly rabbits, but also deer and woodchucks. The strong and persistent winds have caused some desiccation of flower buds on late blooming azaleas and the tender foliage of a few perennials but overall the damage is minimal. Perhaps the most insidious of invasive herbaceous plants is garlic mustard and it is now in bloom. This is a crucial time for removing these plants as a single specimen is capable of producing as many as 8000 seeds. The plants can be easily pulled up now. Mowing them down may not do any good as the remaining stems can regenerate new growth and subsequent flowering. Likewise, the trimmed shoots should be removed from the site if they were in flower as seed development will continue in the severed stems. Volutella blight was observed on Pachysandra terminalis. Management of the disease, including removal of infected plants, now is important since spore development of the fungus and subsequent infections will occur through the summer and fall.

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 to sample submission. Once the lab is allowed to reopen and resume activities, we will share that information immediately.

Disease pressure has remained low with the cold temperatures but that will change in a hurry with the warming conditions upon us now. Many fungal and bacterial pathogens require temperatures within a generally mild range (and at a minimum >40°F for any growth) along with free moisture on plant surfaces in order for spores to germinate and invade. However, an important component to this dynamic is the time frame that temperatures remain in the optimal range and that free moisture is present. This is why the disease triangle was expanded to the disease square (pathogen, host, environment and time). Now that high temperatures will be at or above 70°F and nights won’t be approaching freezing (hopefully?), numerous infections will develop during and after rain events. Scout for anthracnose diseases on deciduous trees and shrubs, such as maple and dogwood, among many others. Several foliar pathogens that cause symptoms later in the season (oak leaf blister, Rhizosphaera needle cast, Tubakia leaf blotch, Septoria leaf spot) infect leaves and needles in the spring and go through a long latent phase. In many cases, there’s little we can do about this considering the high level of inoculum present in the environment.

We are entering the time of year when eastern white pines impacted by needle blight, along with other pests and pathogens will appear at their worst. https://ag.umass.edu/landscape/fact-sheets/dieback-of-eastern-white-pine  As new candles elongate, older needles will continue to turn brown and prematurely shed from the canopy. In early June, the trees can appear very thin but many seem to persevere through and fill out as the current season’s growth matures. Consider some form of nitrogen fertilization to make up for the loss of last year’s foliage.

Be on the lookout for beech leaf disease as new growth develops and report any possible sightings for confirmation.

Unfortunately, a common ailment that plants suffer from this year is “rough handling disease”. Arborvitae in particular seem especially prone, due to their popularity for screening. While trees and shrubs don’t need to be treated like porcelain dolls, be mindful of the stem and branch breakage that can result from delivery from the nursery and subsequent planting. Trees and shrubs transported in the bed of a truck should be covered in some fashion. Typical speeds on state roads or the highway, even for relatively short distances, will result in winds rarely experienced in the landscape. Some injury is to be expected during transplanting, of course. Remind clients that the shock of transplant may result in very stunted growth for one to three years and conifers may shed a large volume of older needles during the first growing season.

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 pending.

The first webinar in this series will happen LIVE on:

Thursday, May 21, 2020 (Noon – 1:00 PM)

Research Updates: Chemical Management of the Spotted Lanternfly

Dr. Phil Lewis, Project Leader with the APHIS Otis Laboratory

This talk will give a brief overview of the biology and current distribution of the Spotted Lanternfly. Additional topics covered will focus on currently used treatments by arborists, alternative treatment methods and chemistries, and will wrap up with a short report on the status of a biological control effort for this invasive planthopper. Preregistration is required to access the webinar.

Don’t miss this excellent opportunity! For more information about all of the webinars in this series and to register, 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 .

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.
• 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 2019, increased populations of bagworms were observed and reported. 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 soon 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 ‘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.
• 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 approximately 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.
• 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 .

• 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 with 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 which 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. 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.

 

• 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. 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.
• 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).
• 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. 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.
• Taxus Mealybug: Dysmicoccus wistariae will produce honeydew which leads 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.
• 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 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. Management in nurseries or Christmas tree production may be necessary. Target adults between 7-58 GDD’s.
• 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

A member of the lily plant family (Liliaceae), star-of-Bethlehem, Ornithogalum umbellatum is currently apparent in some turf and landscape areas. Visit https://extension.umass.edu/landscape/weeds/ornithogalum-umbellatum for photos and characteristics. Star-of-Bethlehem can be difficult to control. Glyphosate will control star-of-Bethlehem in the landscape. Several of the non-chemical, burn-down herbicides will desiccate the leaves and over time will weaken the bulb of this weed. Star-of-Bethlehem is very susceptible to the broadleaf turf herbicide sulfentrazone. Sulfentrazone is found in several 2-, 3- and 4-way broadleaf turf herbicide combinations and in combination with carfentrazone in the herbicide Dismiss NXT^tm. Sulfentrazone alone can be found in several post-patent, generic products. Consult with your distributor for the product options available.

Wild garlic, Allium vineale, is visible in turf and landscape settings now. Wild garlic is also called field garlic. Other common names include crow garlic, stag's garlic and on rare occasions wild chives. Visit https://extension.umass.edu/landscape/weeds/allium-vineale to see images and identification characteristics. Wild onion, Allium canadense, is a closely related species and is less common in New England. Managing this species in turf and landscape is often unnecessarily difficult for turf and landscape professionals as herbicide control can be very effective. Like garden onions, wild garlic has a very waxy leaf. This wax results in a large amount of an herbicide spray application running off the leaf with little or no plant uptake occurring. When growing in turf, a broadleaf turf herbicide will control wild garlic. In the landscape, a directed-spray treatment of glyphosate will be effective. To overcome the “waxy-leaf-herbicide-runs-off” problem, it is best to step on the plant prior to treatment. Stepping on the plant will lay it horizontally and so less herbicide spray will run off the leaves. Stepping on the plant results in some mild wax disturbance which will also aid in herbicide absorption.

Treat garlic mustard, Alliaria petiolata, now while it’s in its flowering period. Applications at this time of year will control second year plants before they go to seed as well as first year seedlings. Look for seedlings at this time as these seedlings will be next year’s flowering plants.

Landscape mulch should be the first defense against weeds in landscape beds. Mulch can be done now at the beginning of the season before summer annual weeds germinate. Small winter annual weeds can be smothered with mulch. Freshly mulched landscape beds will not immediately require a preemergence herbicide application because the fresh mulch should supply adequate summer annual weed control in the short term. Preemergence herbicide application should be considered on mulched areas that have not been freshly mulched or can be applied later in the season in those areas that were freshly mulched this spring. Preemergence herbicides should be applied on top of landscape mulches, not underneath them. Compost is not recommended as a mulching material.

Inspect areas of landscape where new trees or shrubs, especially those that were field grown, have been planted in the last year. Look for perennial weeds that may be growing from the root ball. Canada thistle, mugwort, quackgrass, bindweed and horsenettle are some of the possible culprits. Perennial weeds can be spot treated with glyphosate products.

Japanese knotweed, Polygonum cuspidatum, has emerged from rhizomes in far too many areas of New England and stalks can be 3 - 4 feet in height by now. Do not attempt to control this weed at this time as herbicide applications are not effective at this time of year. Repeat cutting or mowing can be used as a non-chemical strategy and should have started when the stalks were 4 to 6 inches high. Repeat cutting or mowing should be done as regrowth reaches 4 to 6 inches in an effort to “starve” the underground rhizomes.

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.

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. Alternatively, call the lab at (413) 545-2311. No samples are being accepted at this time.

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