Landscape Message: May 14, 2021

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

The Landscape Message will be updated weekly in May. The next message will be posted on May 21. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list 

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

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Scouting Information by Region

Environmental Data

The following data was collected on or about May 12, 2021. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via regional NEWA stations for the 2021 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.

MA Region/Location	GDD		Soil Temp (°F at 4" depth)		Precipitation (1-Week Gain)	Time/Date of Readings
	1-Week Gain	2021 Total	Sun	Shade
CAPE	19	89.5	55	51	1.12	12:00 PM 5/12
SOUTHEAST	26.5	122.5	69	54	1.01	3:30 PM 5/12
NORTH SHORE	30	129.5	53	47	0.48	10:30 AM 5/12
EAST	28	141	62	54	0.35	4:00 PM 5/12
METRO	22.5	130.5	51	47	1.57	5:30 AM 5/12
CENTRAL	18.5	133.5	54	52	0.67	7:00 AM 5/12
PIONEER VALLEY	14.5	135.5	55	51	0.85	11:00 AM 5/12
BERKSHIRES	0	79.5	53	46	0.90	8:15 AM 5/12
AVERAGE	20	120	57	50	0.87	_
n/a = information not available

Drought has recently been alleviated in MA - check here: https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.aspx?MA

Phenology

Indicator Plants - Stages of Flowering (BEGIN, BEGIN/FULL, FULL, FULL/END, END)
PLANT NAME (Botanic/ Common)	CAPE	S.E.	N.S.	EAST	METRO W.	CENT.	P.V.	BERK.
Aesculus hippocastanum (common horsechestnut)	*	*	*	*	*	*	Begin	Begin
Rhododendron carolinianum (Carolina rhododendron)	Begin	*	*	Begin	*	*	Begin	*
Deutzia spp. (Deutzia species)	Begin	Full	Begin	Begin	Begin	Begin	Begin	*
Spiraea x vanhouttei (Vanhoutte spirea)	*	Full	*	Begin	Begin	Begin	Begin	*
Elaeagnus umbellata (autumn olive)	Begin/Full	Full	Full	Full	Full	Full	Full	*
Syringa vulgaris (common lilac)	Full	Full	Full	Full	Full	Full	Full	Begin/Full
Cornus florida (flowering dogwood)	Full	Full/End	Full	Full	Full	Begin/Full	Full	Begin/Full
Rhododendron spp. (early azaleas)	Begin/Full	Full	Full	Full	Full	Full	Full	Full
Malus spp. (crabapple)	Full	Full/End	Full	Full	Full/End	Full	Full/End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature from May 5 to May 12 was 51˚F, with a high of 65˚F on May 11 and a low of 40˚F on May 7. The period was much sunnier than the previous period, with May 8 being the only completely cloudy day. Just over 1 inch of precipitation fell primarily on May 10, plus a little on the afternoon of May 5. Herbaceous plants in bloom include brunnera, pulmonaria, epimedium, fringed bleeding heart, merry bells, may apple, yellow alyssum, barren strawberry, common violet, lily of the valley, Solomon’s seal, vinca, money plant, creeping phlox, tulips, grape hyacinths, and some late daffodils. Woody plants in bloom include Japanese flowering cherry ‘Kwanzan’, eastern redbud, flowering dogwood, saucer magnolia, Korean spice viburnum, Kerria japonica, bush honeysuckles, and PJM rhododendron. Forsythia bloom is just about at its end.

Pests/Problems: Lots of questions about damaged rhododendrons have been pouring in. The dieback is primarily a result of last season’s drought, exacerbated by winter and soon to be susceptible to disease. Prune out damaged limbs. There are a great many dead arborvitae as well for the same reasons. Winter moth caterpillars are about 1cm in length at this time and have been seen on susceptible hosts such as maple, oak, apple and blueberry, in the past week. Winter moth populations are not expected to cause defoliation, but holes are likely to be seen in the leaves of host plants. An area in Mashpee with fall cankerworm defoliation last year yielded no signs of them this year. As caterpillars, winter moth and fall cankerworm can be differentiated by the number of prolegs - winter moth having two and fall cankerworm having two and half. Lecanium scale is still present in high numbers in some locations and in other locations appears to be under control by entomopathogenic fungi. Scout for lecanium scale to determine whether treatment is necessary. The time to target this insect with dormant oil is still in play but only for a short while longer. Oak decline and mortality continue with white oak being harder hit. In many areas, scattered white oaks can be seen that look like they may not leaf out this year. Lichens are a good indicator of trees with chronic stresses – especially oaks.

Other pests or damage seen in the past week include hemlock woolly adelgid on hemlock, spruce spider mite on Alberta spruce, boxwood leafminer damage on boxwood, tulip fire on tulips, iris borer on bearded iris, and sycamore anthracnose on sycamore. Weeds seen in bloom include garlic mustard, cypress spurge, dandelion, annual bluegrass, common violets, yellow rocket, chickweed, and speedwell. Bittercress and arabidopsis are going ballistic at this point. The weather during this period was ideal for good weed seed germination. Red thread showed up big time late last week. Low maintenance fine fescue lawns always seem to be the lawns most affected. Rabbits continue to mow down favorite plants. Protect yourself from ticks! (See the Insect report below.)

Southeast Region (Dighton)

General Conditions: Among the many plants in flower I've noticed these: Alliaria petiolata (garlic mustard), Aquilegia (columbine), Arisaema triphyllum (Jack in the pulpit), Aurinia saxatilis (basket of gold), Barbarea vulgaris (yellow rocket), Cercis canadensis (redbud), Chelidonium majus (greater celandine), Chaenomeles (flowering quince), Conium maculatum (poison hemlock), Convallaria majalis (lily of the valley), Cornus florida (flowering dogwood), Dicentra eximia (fringed bleeding heart), Deutzia spp., Elaeagnus umbellata (autumn olive), Euphorbia epithymoides (yellow/cushion spurge), Fothergilla major (mountain witch alder), Geranium maculatum (wild geranium), G. sanguineum (cranesbill geranium), Halesia carolina (Carolina silverbell), Hyacinthoides hispanica (wood hyacinth), Iberis sempervirens (candytuft), Ilex x meserveae (blue holly), Iris germanica (German iris), Kerria japonica 'pleniflora', Lamprocapnos spectabilis (bleeding heart), Lonicera morrowii (Morrow's honeysuckle), Lunaria annua (honesty), Magnolia x soulangeana, Malus (apples, crabapples), Narcissus (daffodils), Osmunda claytoniana (interrupted fern), Ornithogalum (star of Bethlehem), Paeonia (herbaceous peony), Phlox subulata (creeping phlox), Polygonatum biflorum (Solomon's seal), Potentilla simplex (oldfield cinquefoil), Prunus glandulosa (dwarf flowering almond), P. martima (beach plum), P. serrulata (Kwanzan cherry), P. virginiana, (chokecherry), Pulmonaria (lungwort), Vaccinium corymbosum (highbush blueberry), Veronica filiformis (slender speedwell), Viburnum burkwoodii (Burkwood viburnum) V. plicatum, (double-file viburnum), Viola papilionacea (common blue violet), V. tricolor (Johnny-jump-up), Vinca minor (periwinkle), Ranunculus repens (creeping buttercup), Rheum rhabarbarum (rhubarb), Syringa vulgaris (common lilac), Tulipa, Trillium grandiflorum (white trillium), and T. sessile (toadshade).

Pests/Problems: The following were observed: horns on cedar-apple rust galls on juniper (also see Disease report this issue below), European pine sawfly on mugo pine, red thread on turf, and eastern tent caterpillar on black cherry. Ticks continue to be ubiquitous, so pay particular attention to pets and children. With many plants having leafed out, insect and disease issues have become more prevalent. It's time to make regular surveys of your plants to ensure issues don't get ahead of you. Those voracious caterpillars can defoliate your prize if you turn your back on them. Be sure to properly identify the larvae, choose the lowest impact management option available, and read thoroughly any product labels to avoid killing beneficial insects such as pollinators.

North Shore (Beverly)

General Conditions: Most of the days during this period were sunny with lower than average temperatures for this time of the year. Daytime temperatures were in the mid-50s to low 60s and night temperatures were in the low to mid-40s. The average daily temperature for this period was 53°F with the maximum temperature of 65°F recorded on May 9 and minimum temperature of 40°F recorded on May 8. Approximately 0.48 inch of rainfall was recorded at Long Hill, all on one day - May 10. Due to the nice weather during this week, landscapers and homeowners were busy doing spring cleanup. Many more plants were observed in bloom this week and the flowers are lasting longer on the plants due to cooler weather. Woody plants seen in bloom during this reporting period include: beach plum (Prunus maritima), wayfaring tree (Viburnum lantana), mountain pieris (Pieris floribunda), flowering dogwood (Cornus florida), redbud (Cercis canadensis), large fothergilla (Fothergilla major), dwarf fothergilla (Fothergilla gardenii), common lilac (Syringa vulgaris), Chinese lilac (Syringa x chinensis), Kwanzan cherry (Prunus serrulata), crabapple (Malus spp.), Sargent crabapple (Malus sergentii), silverbell (Halesia carolina), Catawba rhododendron (Rhododendron catawbiense), Olga Mezitt rhododendron (Rhododendron ‘Olga Mezitt’), apple trees (Malus spp.) and highbush blueberry (Vaccinium corymbosum). Non-woody plants seen in bloom include: daffodil (Narcissus spp.), forget me not (Myosotis sylvatica), tulips (Tulipa spp.), bleeding heart (Dicentra spectabilis), Siberian iris (Iris sibirica), trillium (Trillium grandiflorum), barrenwort (Epimedium rubrum), Solomon’s seal (Polygonatum odoratum),vinca (Vinca minor) and money plant (Lunaria annua).

Pests/Problems: One result of moist soil and mild temperatures is that weeds are thriving in some lawns and landscapes. Weeds seen in bloom include: dandelion (Taraxacum officinale), ground ivy (Glechoma hederacea), common blue violets (Viola spp.), garlic mustard (Alliaria petiolata), and purple deadnettle (Lamium purpureum). Ticks and mosquitos are very active. Take care to protect yourself when working outdoors.

East Region (Boston)

General Conditions: The past week has been sunny and breezy. We had a daytime high of 67˚F on May 9 and a low of 53˚F on the 6th. We did gain another 0.35 inches of precipitation, bringing the May total to 1.65 inches. The landscape is looking lush. Many plants are in flower, such as Halesia carolina (Carolina silverbell), Kerria japonica (Japanese kerria) and Vaccinium corymbosum (highbush blueberry).

Pests/Problems: Precipitation during the reporting period has alleviated the region’s near drought conditions. Soil is adequately moist and weeds continue to thrive. Japanese knotweed (Fallopia japonica) is 3 feet tall and growing. There is still time to cut garlic mustard (Alliaria petiolata) flower heads before it goes to seed. Black swallowwort (Vincetoxicum nigrum; syn. Cynanchum louiseae) has emerged. Viburnum leaf beetle larvae are actively feeding on viburnum foliage. Hydrangea leaftier continue to sew up terminal hydrangea foliage. An insignificant number of winter moth caterpillars have been seen feeding on roses and cherries. Several Viburnum carlesii (Koreanspice viburnum) have been observed with contorted and twisted foliage; basically an aesthetic issue caused by an abundance of feeding aphids.

Metro West (Acton)

General Conditions: Weather this past week was typical for a New England spring. It was cool, warm, windy, and wet on any given day. The highest temperature recorded for this week was 67°F on the 9^th and the lowest temperature recorded was 39°F on the 7^th and 8^th. The average monthly rainfall for May is 4.04” and as of the 11^th, I have recorded 2.43”. 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), Aronia arbutifolia (black chokecherry), Cercis canadensis (redbud), C. canadensis ‘Alba’ (white flowering redbud), Cornus florida (dogwood), Daphne x burkwoodii ‘Carol Mackie’ (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 (Japanese kerria), Magnolia x loebneri 'Merrill', (Merrill magnolia), M. 'Butterflies' (butterflies magnolia), M. 'Yellow Lantern’ (yellow lantern magnolia), Malus spp. (apple, crabapple), Prunus japonica (flowering almond), Rhododendron spp. (early flowering rhododendron/azalea), Sambucus racemosa ‘Lemony Lace’ (Lemony Lace elderberry), Spiraea spp. (bridal wreath), Syringa spp. (early blooming lilac), Syringa vulgaris (common lilac), Vaccinium angustifolium (lowbush blueberry), V. corymbosum (highbush blueberry), Viburnum carlesii (Korean spice 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: Ajuga reptans (bugleweed), A. nemorosa (wood anemone), Aquilegia canadensis (columbine), Arisaema triphyllum (Jack-in-the-pulpit), Aurinia saxatilis (basket of gold), Brunnera macrophylla (alkanet), Caltha palustris (marsh marigold), Camassia scilloides (wild hyacinth), Chrysogonum virginianum (green and gold), Claytonia virginica (Virginia spring beauty), Convallaria majalis (lily of the valley), Dicentra eximia (fringed bleeding heart), D. spectabilis (old fashioned bleeding heart), D. spectabilis ‘Alba’ (white flowering old fashioned bleeding heart), Epimedium x versicolor 'Niveum' (white flowering barrenwort), E. x versicolor 'Roseuem' (pink flowering barrenwort), E. versicolor 'Sulphureum' (yellow flowering barrenwort), Erythronium americanum (yellow trout-lily), Gallium odoratum (sweet woodruff), Geranium maculatum (wild geranium), G. macrorrhizum (bigroot geranium), Helleborus niger (Christmas rose), Hyacinthoides hispanica (wood hyacinth), Iberis sempervirens (evergreen candytuft), Iris cristata (crested iris), I. germanica (bearded iris), Lamium maculatum (dead nettle), Linaria annua (money plant), Mertensia virginica (Virginia bluebells), Myosotis sylvatica (forget-me-nots), Narcissus spp. (daffodil), Nepeta spp. (ornamental catmint), Omphalodes verna (blue-eyed Mary), Phlox subulata (moss phlox), Polygonatum commutatum (Solomon’s seal), P. odoratum 'Variegatum' (variegated Solomon’s seal), Primula spp. (primrose), Pulmonaria longifolia (lungwort), P. rubra (salmon colored lungwort), Stylophorum diphyllum (wood poppy), Tiarella cordifolia (foam flower), Trillium erectum (red flowering trillium), T. grandiflorum (white flowering trillium), T. sessile (toadshade), Tulipa spp. (tulip), Veronica umbrosa 'Georgia Blue' (speedwell), Vinca minor (periwinkle), and Viola spp. (violet).

Pests/Problems: With the late April and early May rain events, the moderate drought declaration for the metro west area has been lifted and has been declared to be in a normal condition. One of our most invasive herbaceous weeds, Alliaria petiolata (garlic mustard), is in full bloom at this time and can easily be spotted because of its white flowers and invasiveness anywhere and everywhere - including on roadsides, in woodlands, in wetlands, and in gardens. Eleagnus angustifolia (Russian olive), a woody invasive shrub/small tree is also flowering and can easily be detected by its silvery leaves and thorny branches. Black flies are active and out in force. Be aware of Toxicodendron radicans (poison ivy); it is beginning to leaf out, so it is easy to detect its shiny red leaves of three.

Central Region (Boylston)

General Conditions: It seems like just about everything is now in bloom. Due to the cooler temperatures we’ve been experiencing, many of our early bulbs are still blooming. Daffodils are mostly finished, but some later blooming cultivars are still going strong. Tulips are just past peak, and many of our spring flowering shrubs are beginning to bloom. Magnolias are finishing bloom, cherries and crabapples are still flowering well. Drought concerns have largely been alleviated for the time being thanks to some much-needed, prolonged rain storms recently. Depending on the source, the spring frost free date for the central region is anywhere from May 9 - May 31. On average, mid-May is generally a safe time to begin planting annuals and vegetables outdoors. Evening temperatures still consistently drop into the lower 40’s and upper 30’s for another week or two, so be careful when moving cold sensitive houseplants outdoors until the end of May.

Pests/Problems: Common garden weeds are really going strong. Lawn weeds like dandelion have for the most part finished their first flowering flush and set seed. Poison ivy has broken bud and begun growing. Garlic mustard has been flowering for about 10 days. Pull it, bag it, and dispose of it in the trash to prevent fruit from maturing and distributing seed.

Pioneer Valley Region (Amherst)

General Conditions: It’s been a cool start to May in the Pioneer Valley as we approach the mid-month marker. Temperatures have been unseasonably cool this month, with highs reaching into the lower to mid-60s and lows in the upper 30s to low 40s. The cold nighttime temperatures have slowed leaf and shoot development but prolonged flowering for certain plants. Conditions have ranged from overcast with scattered rain showers to sunny and breezy. Oh, the wind… it just won’t go away this spring and has made conditions feel much cooler at times than the temperature would suggest. Usually by June, the valley winds have calmed and humidity levels start to rise. April temperatures were slightly above-average through the valley, according to the NRCC, buoyed by warm temperatures early in the month. From 4/6 through 4/10, we experienced high temperatures ranging from 69–79°F. A month later, high temperatures from 5/6 through 5/10 peaked at only 62–67°F. Despite >5” of rain in a 12-day span (4/29 through 5/10) at the Easthampton gauge, the region was classified as abnormally dry until just a few days ago, according to the U.S. Drought Monitor. Despite the recent dryness, soil moisture is now plentiful in most settings. Yet, the low humidity and winds are drying out the uppermost soil horizon in full sun settings, so regularly check recently transplanted trees and shrubs to ensure the root ball is staying moist during this critical post-planting period. Soil temperatures have remained roughly the same over the past week due to the cool nights. Pollen counts are high right now, with large Norway spruce and eastern hemlocks producing visible green clouds. While white pines are often blamed, they are not dispersing pollen right now.

Pests/Problems: We’re still in the honeymoon phase of the landscape season, when trees and shrubs are putting on new growth and looking their best. Foliar diseases are hard to find, with even horse chestnut leaves looking pristine. But fungal spores are blowing in the wind and infections will appear, inevitably. The European elm scale (Eriococcus spurius) can be seen on trunks and branches of disease-resistant American elms in the landscape. They congregate in bark crevices/depressions and the bark will have a dark appearance due to the growth of sooty mold fungi. Hemlock woolly adelgid is abundant this season and eastern hemlocks with significant infestations should be treated. Population swoons are normal for this invasive pest and overwintering success is high this year. Scout for spruce spider mite symptoms (flecking) on arborvitae and spruce. Damage will be most apparent right now on interior canopy needles. Large Norway spruce can have significant populations of this common landscape pest. Hydrangea leaftier (Olethreutes ferriferana) was observed on Hydrangea arborescens. The youngest leaves are threaded together for protection while feeding. Gently prying open the leaves and destroying the caterpillars is the path of least resistance for control. Small, green-colored leafroller caterpillars can be abundant on young landscape trees. It can be difficult to identify these pests to species, since so many appear similar at this early stage. Hosts can range from oak, stewartia and Japanese maple to dogwood. Orange-colored telia produced by the cedar-apple rust pathogen have been abundant on landscape junipers and eastern red cedar. Prune out the galls on smaller trees and destroy them. Stem cankering caused by the formation of the galls is more common on J. scopulorum. The window for certain white grub treatments is closing, so make applications as needed. Rodent tunneling in landscaped beds may be related to high grub populations. Specifically, northern short-tailed shrews and eastern moles may be tunneling to consume grubs (and earthworms).

Berkshire Region (Great Barrington)

General Conditions: At times over the past week, it felt more like mid-March than mid-May. Daytime temperatures were mostly in the upper 40s and low 50s for highs and 30s for overnight lows. Richmond recorded a low of 32˚F on the morning of May 7^th. However, it was the winds which left one feeling cold despite the temperatures. Year-to-date precipitation as of May 12 was less than an inch below normal. We’ve made up a deficit of over 4 inches in just the past two weeks. Soils are very moist, even saturated and muddy in some areas. Plant development overall has been slow, though turf grass has not been affected and is growing rapidly.

Pests/Problems: Cool temperatures have slowed not only plant development but also that of many insects. It has not, however, affected the population of black-legged ticks as the reports and complaints of tick bites continue unabated. A mix of larvae and pupae of the boxwood leaf miner was found when dissecting a sample of leaves from boxwood shrubs. Boxwood psyllid is active at this time. Spruce spider mites remain active. The first signs of apple scab were found on crabapple foliage. Small mammal pests, i.e. meadow voles, chipmunks, and rabbits, are very abundant and causing some browsing damage to the foliage of spring flowering bulbs as well as to emerging shoots of herbaceous perennials. Along with the rapid growth of turfgrass is the steady appearance of weeds – in turf and in flower and shrub borders. Garlic mustard (Alliaria petiolata) is one which needs immediate attention as the flowers are maturing and will be producing its seed pods soon. This invasive weed is allelopathic and releases chemicals which inhibit the growth of herbaceous plants, including grasses.

Regional Scouting Credits

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

Woody Ornamentals

Diseases

Tune in for a special Urban Forestry Today webinar at 12:00 pm (EST) on Thursday, 5/20 (http://www.urbanforestrytoday.org/) presented by Cameron McIntire (USFS Forest Pathologist) and Nicholas Brazee (UMass Extension Plant Pathologist). The first half of the webinar (McIntire) will focus on two of the primary contributors to eastern white pine decline (white pine needle damage and Caliciopsis canker) while the second half (Brazee) will focus on important landscape diseases of conifers in the landscape. White pine needle damage is most conspicuous in late May to early June in the northeast, as the new needles are expanding, so this webinar is well-timed.

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

• In the spring and early summer, a highly conspicuous orange-colored slime can be observed on branches or the main trunk of certain hardwoods, such as Styrax and Cornus. The slime is a mixture of various fungi, yeasts and bacteria. But one fungus, Fusicolla merismoides, is often very abundant and the source of the orange color. These organisms are growing on the sugar-rich sap that flows from freeze cracks, pruning wounds or other types of injuries that result in sap flow. While alarming, these organisms do not cause disease or represent a threat to overall health.

 

• Early May is a good time to see the cedar-apple rust pathogen, Gymnosporangium juniper-virginianae, sporulating on eastern redcedar (Juniperus virginiana). Orange-colored telia emerge from rounded galls and become gelatinous after periods of rain. Basidiospores produced on Juniperus are dispersed and infect Malus in the landscape, usually nearby crabapples.

 

 

• Ploioderma needle cast, caused by Ploioderma lethale, on Austrian pine (Pinus nigra). The tree is 25-years-old and has been present at the site for over 20 years. In the spring, the needles become brown and spotted. The tree receives full sun in a mulched planting bed with irrigation. Closer examination shows that many of the needles have blighted tips but the base of the needle remains green. This is often a diagnostic symptom of Ploioderma needle cast. The spore-bearing structures (hysterothecia) are readily visible in the field with the aid of a hand lens. These swell in late spring to early summer and liberate spores that will infect the newly developing needles. While infected, the current season’s needles remain asymptomatic until the winter or following spring. Austrian and pitch pine are the most common hosts in our region. The infected tree was treated with a trunk injection in September of 2020 to combat the chronic cycle of infection.
• Needle cast of blue spruce (Picea pungens) caused by Rhizosphaera kalkhoffii and Stigmina lautii. The tree is approximately 20-years-old and has been present at the site for many years. The trees receive morning sun as part of a border screen between two residential homes. The spruce were interplanted with pines in a mulched bed. Over the past several years, lower branch dieback has intensified and is progressing upwards in the canopy. Rhizosphaera and Stigmina were found co-occurring on symptomatic needles submitted for analysis. Over time, needle blight infections cause a decline in vigor and ruin the aesthetic value of the tree. Pruning of lower canopy branches should be conducted as soon as symptoms first appear. Fungicide applications can be difficult in dense, residential settings and often have limited results.
• Canopy dieback on a weeping Japanese maple (Acer palmatum) caused by Phomopsis. The tree is approximately 25- to 30-years-old and has been present at the site for nearly as long. It receives full sun in soils composed of sand and loam. Last spring, 25% of the canopy did not leaf out and the dieback appears to be worse this spring. Submitted stems were discolored (grey to black) and there were clear signs of fungal infection. Phomopsis can be an aggressive pathogen on Japanese maples when predisposing stresses weaken the tree’s defenses. The dense canopies and thin bark make them prone to cankering outbreaks. There was no sign of insect infestation or any symptoms of Verticillium wilt.
• Infestation of the juniper webworm (Dichomeris marginella) on a blue-needled creeping juniper (likely J. squamata ‘Blue Star’). The plant is approximately 15-years-old and receives full sun in well-drained soils. For the past three years, needle browning and branch dieback has occurred. Previously, the dead tissue was pruned out and leaf compost was added in the expectation the plant would recover. While the pruning likely removed a good percentage of the webworm population, further intervention will be needed to eradicate the infestation. The juniper webworm is a small moth that primarily infests Juniperus but can occasionally occur on Thuja. Significant infestations of this non-native pest result in needle/branch dieback, poor vigor and reduced aesthetic value. Mature webworm larvae create nests of silken threads, dead needles, frass and other plant debris, as pictured here.
• Severe infestation of the spruce spider mite (Oligonychus ununguis) on Norway spruce (Picea abies). In addition to the SSM, a minor infestation of the eastern spruce gall adelgid (Adelges abietis) and spruce bud scale (Physokermes piceae) were also detected. The site has a row of 30 trees that are approximately 20-years-old. They were transplanted four years ago and receive full sun in well-drained soils with drip irrigation. Two of the trees have experienced ~50% needle loss while nearly all the trees have a chlorotic appearance, especially on the western side of the canopies. The SSM infestation was severe, based on the submitted sample. The older needles were more heavily infested while last year’s (2020) needles and shoots were undersized. There were no needle blight or stem cankering pathogens, although they may certainly be present. The SSM is generally a cool season mite and thrives during extended dry periods.

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

Insects

In the News:

• Periodical Cicadas: Magicicada spp. have been the topic of conversation in the news because entomologists are anticipating the upcoming emergence of Brood X. (X being the Roman numeral for 10.) Brood X last emerged in 2004 and is set to emerge (after 17 years) in late May and early June in the northern portions of their range, sooner in the south. Brood X will be experienced regionally by the following states: DE, GA, IL, KY, MD, MI, NC, NJ, NY, OH, PA, TN, VA, and WV. As you can see, Massachusetts is not on that list. The next time Brood X will make an appearance is 2038. For parts of Massachusetts, historically, Brood XIV is the one that we need to watch, which is on track to emerge again in 2025 – something to look forward to! (Brood XIV is regionally distributed across KY, GA, IN, MA, MD, NC, NJ, NY, OH, PA, TN, VA, and WV and was last active in 2008.) But for this year, 2021, Massachusetts will miss out on much of the magical periodical cicada fun.

Periodical cicada species emerge every 13 to 17 years, depending upon the species. 17-year cicada species, such as those representing Brood X, include Magicicada septendecim, M. cassini, and M. septendecula. 13-year cicada species include Magicicada tredecim, M. neotredecim, M. tredecassini, and M. tredecula.

Periodical cicadas cause injury to a wide variety of deciduous trees and shrubs, but oaks are primary hosts. Females cause damage when they lay a series of small groups of eggs (inserting them into twigs). Small branches may be girdled or killed by this process. The damage may also predispose the impacted branches to breakage and allow for easy-access by pathogens. Adults feed on the fluids they extract from twigs, and the nymphs feed in a similar manner on the roots of trees. Injury as a result of this feeding is considered to be minor. Broods of periodical cicada adults have synchronized emergence events every 13 or 17 years. These events can be loud and very noticeable to the public. Many people incorrectly categorize periodical cicadas with Biblical locusts.

The immature stages of these insects live on the roots of trees and shrubs, growing very slowly. In the case of Brood X, in the 17^th year of their life (now) they will emerge from the soil, usually in late-May to early-June. As they emerge, they can climb trees, buildings, and all other manner of upright structures. They shed their nymphal skins (many of which remain visible to observers stuck to these objects) and adults move to the trees. Adults will conduct a bit of feeding, and males make their well-known “buzzing” sound to attract females to mate. Females will then use their ovipositor (egg-laying structure) to insert their eggs into the twigs of trees and shrubs. Six to ten weeks later, those eggs will hatch, and nymphs will move to the ground where they will dig into the soil and begin feeding on host plant roots. After that time, their underground stages will go largely unnoticed until the next adult emergence event.

In addition to periodical cicadas, Massachusetts is home to dog-day cicada species (Tibicen spp.). These are the largest cicadas in North America, and are much less commonly observed (but frequently heard). Males make the loud, long, buzzing sounds that mark our summer days. These species are sometimes called annual cicadas, as the adults emerge each year. Nymphs take 2-5 years to develop, but overlapping generations result in annual adult appearance.

An important thing to remember about periodical cicadas, even though they may be quite the event for people living in Brood X territory these days, is that they are native to North America and have evolved with our forests. Some research suggests that they are natural pruners of trees, their oviposition damage actually leading to fuller canopies by removing branch tips. When they die, the adult cadavers return nutrients to the soil. Mammals and birds eat them. And after 2021, folks in the Brood X range will not need to worry about them again until 2038.

Looking for more information about periodical cicadas? Check out these resources:

Cicada Safari: https://cicadasafari.org/

Penn State Extension: https://extension.psu.edu/periodical-cicada

Ohio State University Extension, BYGL: https://bygl.osu.edu/node/1759

 

Upcoming Educational Programs:

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

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

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

June 8 – Tick Topics:

• 10:00 – 11:00 AM: Tick Management in the Landscape, Larry Dapsis, Cape Cod Cooperative Extension
• 11:10 AM – 12:10 PM: The Outreach Hiker’s Guide to Tick-ology: Personal tick bite prevention and more! Blake Dinius, Plymouth County Extension

June 15 – Mosquito Topics:

• 10:00 - 11:00 AM: Mosquitoes in Massachusetts, Arboviruses and Protecting Yourself, Dr. Jennifer Forman Orth, MA Dept. of Agricultural Resources
• 11:10 AM – 12:10 PM: Dealing With the Asian Tiger Mosquito: Incorporating an Invasive Species into an Existing Mosquito Control Program, Priscilla Matton, Superintendent, Bristol County Mosquito Control Project

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

 

Insects and Other Arthropods of Medical Importance:

• American Dog Tick: Anecdotally, Dermacentor variabilis adults are prevalent in certain locations of Massachusetts at this time. Reports from Cape Cod of adult dog ticks crawling on the siding of homes have been noted. Photographic evidence of adult dog ticks crawling up metal objects leaning against a home located in a heavily wooded area of Berkshire County, MA have also been reported recently (5/9/2021). The images shown here are adult stage dog ticks removed from a dog following a roadside walk in Hampshire County on both 5/6/21 (4 ticks removed) and 5/7/21 (3 ticks removed).

The American dog tick is found throughout most of North America. It may be encountered in forest edges, fields, along walkways and roadways, sidewalks, and trails. Adult stage ticks may be found on raccoons, skunks, cats, dogs, and other medium-sized hosts. Larvae and nymphs can be found on mice, voles, rats, and chipmunks. Adult males and females are active between April and early-August. Both adult males and females will feed, including on people. Nymphs and larvae of this species rarely attach to people or their pets. This species of tick can transmit lesser-known diseases such as Rocky Mountain Spotted Fever (not frequently infecting humans, according to CDC reports) and Tularemia (rarely infecting humans, according to CDC reports). For more information about the American dog tick, visit: https://web.uri.edu/tickencounter/species/dog-tick/ .

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

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

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

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

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

• 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/mosquitoes/mosquito-bites/prevent-mosquito-bites.html .

 

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

Invasive Insects & Other Organisms Update:

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

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

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

Now is a great time to provide copies of these BMP’s to employees, customers, family, and friends! The more eyes we have out there looking for spotted lanternfly, the better. Use the above BMP’s as a guide to help you inspect certain items coming from CT, DE, MD, NC, NJ, NY, OH, PA, WV, and VA.

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

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

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

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

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

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

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

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

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

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

This wood-boring beetle readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus) and has been reported in cultivated olive (Olea europaea). Adult insects of this species will not be present at this time of year. Signs of an EAB infested tree may include (at this time) D-shaped exit holes in the bark (from adult emergence in previous years), “blonding” or lighter coloration of the ash bark from woodpecker feeding (chipping away of the bark as they search for larvae beneath), and serpentine galleries visible through splits in the bark, from larval feeding beneath. It is interesting to note that woodpeckers are capable of eating 30-95% of the emerald ash borer larvae found in a single tree (Murphy et al. 2018). Unfortunately, despite high predation rates, EAB populations continue to grow.

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

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

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

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

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

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

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

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

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

• White Spotted Pine Sawyer (WSPS): Monochamus scutellatus adults can emerge in late May throughout July, depending on local temperatures. This is a native insect in Massachusetts and is usually not a pest. Larvae develop in weakened or recently dead conifers, particularly eastern white pine (Pinus strobus). However, the white spotted pine sawyer looks very similar to the invasive Asian Longhorned Beetle, Anoplophora glabripennis, ALB. ALB adults do not emerge in Massachusetts until July and August. Beginning in July, look for the key difference between WSPS and ALB adults, which is a white spot in the top center of the wing covers (the scutellum) on the back of the beetle. White spotted pine sawyer will have this white spot, whereas Asian longhorned beetle will not. Both insects can have other white spots on the rest of their wing covers; however, the difference in the color of the scutellum is a key characteristic. See the Asian longhorned beetle entry above for more information about that non-native insect.

• Jumping Worms: In recent years, public concern about Amynthas spp. earthworms, collectively referred to as “jumping or crazy or snake” worms, has dramatically increased. University researchers and Extension groups in many locations in the US are finding that these species cause not only forest ecosystem disturbances, but may also negatively impact soil structure and reduce plant growth in gardens and managed landscapes. They do this by voraciously devouring the organic layer of the soil while feeding very close to the soil surface, unlike other species of earthworms. In woodland areas, they can quickly eat all of the leaf litter on the forest floor. Jumping worms also leave a distinct grainy soil full of worm castings. The soil becomes granular and may look like dried coffee grounds.

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

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

Suggested reading includes Dr. Kostromytska’s recent “Hot Topics” article in Hort Notes (including an identification guide), here: https://ag.umass.edu/landscape/newsletters/hort-notes/hort-notes-2021-vol-323

Additional resources can also be found here:

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

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

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

Tree & Shrub Insects & Mites:

• Bagworm: Thyridopteryx ephemeraeformis is a native species of moth whose larvae construct bag-like coverings over themselves with host plant leaves and twigs. This insect overwinters in the egg stage, within the bags of deceased females from last season. Eggs may hatch and young larvae are observed feeding around mid-June, or roughly between 600-900 GDD’s. Now is the time to scout for and remove and destroy overwintering bags. In certain areas across MA in 2020, increased populations of bagworms were observed and reported, particularly in urban forest settings and managed landscapes. More information can be found here: https://ag.umass.edu/landscape/fact-sheets/bagworm
• Boxwood Leafminer: Monarthropalpus flavus partly grown fly larvae overwinter in the leaves of susceptible boxwood. Yellowish mines may be noticeable on the undersides of leaves. This insect grows rapidly in the spring, transforming into an orange-colored pupa. After pupation, adults will emerge and white colored pupal cases may hang down from the underside of leaves where adults have emerged. Adults may be observed swarming hosts between 300-650 GDD’s, or roughly the end of May through June. Most cultivars of Buxus sempervirens and B. microphylla are thought to be susceptible. If installing new boxwoods this spring, resistant cultivars such as ‘Vardar Valley’ and ‘Handsworthiensis’ are good choices at sites where this insect has been a problem.
• Boxwood Psyllid: Psylla buxi feeding can cause cupping of susceptible boxwood leaves. Leaf symptoms/damage may remain on plants for up to two years. English boxwood may be less severely impacted by this pest. Eggs overwinter, buried in budscales, and hatch around budbreak of boxwood. Eggs may hatch around 80 GDD’s. Foliar applications may be made between 290-440 GDD’s. However, the damage caused by this insect is mostly aesthetic. Therefore, no management may be necessary.
• Cankerworms: Alsophila pometaria (fall cankerworm) and Paleacrita vernata (spring cankerworm) are often confused for winter moth (Operophtera brumata). Cankerworm populations in eastern MA, particularly on areas of Cape Cod, were confused for winter moth in 2019. Spring cankerworm adults are active in February and March, and fall cankerworm adults are active in late November into early December. During these times, both species lay eggs. These native insects most commonly utilize elm, apple, oak, linden, and beech. Eggs of both species hatch as soon as buds begin to open in the spring. Caterpillars occur in mixed populations and are often noticeable by mid-May in MA. Young larvae will feed on buds and unfolding leaves. There are two color forms (light green and dark) for caterpillars of both species. Like winter moth, they will drop to the soil to pupate. This usually occurs in June. Fall cankerworm larvae have three pairs of prolegs (one of which is small so it is sometimes referred to as ½) and spring cankerworm have two pairs. (Winter moth caterpillars also have 2 pairs of prolegs.) If populations are large and damage is noticeable on hosts, reduced risk insecticides such as Bacillus thuringiensis Kurstaki or spinosad may target larvae between 148-290 GDD’s.
• 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 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. Treatments for the crawler, or mobile, stage of this insect may be made in late May through mid-June, or between 360-700 GDD’s, base 50°F. Nitrogen fertilizer applications may make elongate hemlock scale infestations worse.
• Euonymus Scale: Unaspis euonymi is an armored scale that can be found on euonymus, holly, bittersweet, and pachysandra. This insect can cause yellow spotting on leaves, dieback, and distorted bark. For crawlers, early June timing is suggested between 533-820 GDD’s. (Eggs begin to hatch in early June.)
• European Pine Sawfly: Neodiprion sertifer overwinters in the egg stage. Eggs are laid by females the previous season by cutting slits in needles using their ovipositors and depositing 6-8 eggs in each of 10-12 needles. Egg hatch occurs from late-April to mid-May and caterpillars become active roughly between 78-220 GDD, base 50°F. The primary host in MA is Mugo pine but it can be found on Scots, red, jack, and Japanese red pine. It is also found on white, Austrian, ponderosa, shortleaf, and pitch pine when planted near the aforementioned species. This dark colored caterpillar feeds in tight groups and small numbers can be pruned or plucked out of host plants and destroyed. Spinosad products can be used whenever the caterpillars are actively feeding, usually by mid-May and when caterpillars are still small. Bacillus thuringiensis kurstaki is not effective against sawflies.
• Fletcher Scale: Parthenolecanium fletcheri is a soft scale pest of yew, juniper, and arborvitae. Feeding scales, especially on yew, result in honeydew and sooty mold, needle yellowing, and at times, premature needle drop. There is one generation per year. Overwintered second instar nymphs can be targeted between 38-148 GDD’s, base 50°F. Nymphs develop and adult females lay eggs (on average 500-600) in May that hatch by June. Dead females conceal egg masses beneath. Crawlers migrate short distances to branches and may be concentrated on certain branches of a particular plant.
• Forest Tent Caterpillar: Malacosoma disstria egg hatch occurs between 192-363 GDD’s, base 50°F, by mid-late May and caterpillars may be active for at least 5-6 weeks following. Susceptible hosts whose leaves are fed on by this insect include oak, birch, ash, maple, elm, poplar, and basswood. This native insect has many natural enemies, including some very effective pathogens that typically regulate populations. However, outbreaks of this insect can occur on occasion.
• Hemlock Looper: Two species of geometrid moths in the genus Lambdina are native insects capable of defoliating eastern hemlock, balsam fir, and white spruce. Adult moths lay their eggs on the trunk and limbs of hosts in September and October, and eggs will hatch by late May or early June. (L. fiscellaria caterpillars may be active between 448-707 GDD’s.) Monitor susceptible hosts for small, inch-worm like caterpillars. Where populations are low, no management is necessary. Hemlock loopers have several effective natural enemies.
• Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. The overwintering hemlock woolly adelgid generation (sistens) is present through mid-spring and produces the spring generation (progrediens) which will be present from early spring through mid-summer. HWA, unlike many other insects, does most of its feeding over the winter. Eggs may be found in woolly masses at the base of hemlock needles beginning in mid-March. Each woolly mass is created by a female who may then lay 50-300 eggs. Eggs hatch and crawlers may be found from mid-March through mid-July. Infested trees may be treated with foliar sprays in late April to early May, using Japanese quince as a phenological indicator. Systemic applications may be made in the spring and fall, or when soil conditions are favorable for translocation to foliage. Nitrogen fertilizer applications may make hemlock woolly adelgid infestations worse.
• 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 buds of the host begin to open. Young nymphs crawl to the opening leaflets and begin feeding and the most significant damage occurs at that time, when the insect is hidden from view. Nymphs develop into adults around May-July. This insect can be targeted between 58-246 GDD’s, base 50°F.
• Imported Willow Leaf Beetle: Plagiodera versicolora adult beetles overwinter near susceptible hosts. Adult beetles will chew holes and notches in the leaves of willow once they become available. Females lay yellow eggs in clusters on the undersides of leaves. Larvae are slug-like and bluish-green in color. They will feed in clusters and skeletonize the leaves. Most plants can tolerate the feeding from this insect, and foliage will appear brown. Repeated yearly feeding can be an issue, in which case management of the young larvae may be necessary. Take care with treatment in areas near water.

Check out Episode 4 of InsectXaminer to see the imported willow leaf beetle in action and learn more about its life cycle: https://ag.umass.edu/landscape/education-events/insectxaminer

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

Check out Episode 3 of InsectXaminer to see the lily leaf beetle in action and learn more about its life cycle: 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.
• 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. 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.
• 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. Magnification is required to view spruce spider mite eggs. Tapping host plant branches over white paper may be a useful tool when scouting for spider mite presence. (View with a hand lens.) Spider mite damage may appear on host plant needles as yellow stippling and occasionally fine silk webbing is visible.

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

• 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.

• 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/ .
• Woolly Elm Aphid: Eriosoma americanum females lay a single egg in the cracks and crevices of elm bark, where the egg overwinters. Eggs hatch on elm in the spring as leaves are unfolding. Aphids may be active from 121-246 GDD’s, base 50°F on elm. A young, wingless female hatched from the egg feeds on the underside of leaf tissue. This female aphid matures and gives birth to 200 young, all females, without mating. These aphids feed, and the elm leaf curls around them and protects them. By the end of June, winged migrants mature and find serviceberry hosts. Another set of females is produced. These new females crawl to and begin feeding on the roots of serviceberry. Multiple generations occur on the roots of serviceberry through the summer.

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

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

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