Landscape Message: May 10, 2019

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 8, 2019. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2019 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	2019 Total	Sun	Shade
CAPE	9.5	64	58	53	1.15	12:00 PM 5/8
SOUTHEAST	15.5	85	56	50	1.10	7:45 AM 5/8
NORTH SHORE	12	93	51	46	0.56	9:30 AM 5/9
EAST	9.5	110.5	63	58	0.40	5:30 PM 5/8
METRO	16.5	107.5	54	51	0.82	5:45 AM 5/8
CENTRAL	28	119	59	51	0.61	1:20 PM 5/8
PIONEER VALLEY	36.5	128	61	52	0.72	10:00 AM 5/8
BERKSHIRES	40	117	55	50	0.73	9:00 AM 5/8
AVERAGE	21	103	57	51	0.76	12:00 PM 5/8

n/a = information not available

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.
Rhododendron spp. (early azaleas)	Begin	Begin	Begin/Full	Begin	Begin	Begin	Begin	*
Syringa vulgaris (common lilac)	Begin	Begin	Begin	Begin	Begin	Begin	Begin/Full	*
Cornus florida (flowering dogwood)	Begin	Begin	Begin/Full	Begin	Begin	Begin	Begin/Full	Begin
Malus spp. (crabapple)	Begin	Full	Begin/Full	Begin/Full	Full	Begin	Full	Begin
Cercis canadensis (redbud)	Full	Begin/Full	Begin	Full	Full	Begin	Full	Begin
Pyrus calleryana (callery pear)	Full/End	Full	Full/End	Full/End	Full	Full/End	Full/End	Begin/Full
Chaenomeles speciosa (common flowering quince)	Full/End	Full	Full	Full	Full	Full	Full	Full
Amelanchier spp. (shadbush, serviceberry)	Full	Full	End	Full/End	Full/End	Full	End	Full
Rhododendron ‘P.J.M.’	Full/End	Full/End	Full/End	End	Full/End	Full/End	Full/End	Full
Prunus serrulata (Japanese flowering cherry)	End	Full/End	Full/End	End	Full/End	Full	Full	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature from May 1 – May 7 was 49˚F with a high of 63˚F on May 7 and a low of 36˚F on May 1 & May 7. Some areas dropped to 32˚F on the morning of May 7. Just over an inch of rain fell over 5 days during the period keeping things moist and gray. Topsoil and subsoil moisture levels are adequate.

Pests/Problems: Winter moth is still actively feeding. Gypsy moth has not hatched yet. Lecanium scale, primarily on oak should be monitored as many areas have high populations. Boxwood leafminer damage on boxwood – midges have yet to emerge. Conditions for plant diseases have been ideal with consistent rains. Dogwood anthracnose can already be seen extensively damaging flowers before they are fully open. Iris leaf spot can be seen on bearded iris. Daylily leaf streak can be seen on daylily. Brown felt blight was seen on bird nest spruce, tulip fire on tulip. Moisture conditions have also been ideal for germinating seeds both good and bad. Weeds in bloom include mouse-ear cress (Arapidopsis thaliana), mouse ear chickweed (Cerastium vulgatum), lesser celandine (Ficaria verna), dandelion (Taraxacum officinale), garlic mustard (Alliaria petiolata), ivy leaf speedwell (Veronica hederifolia), common blue violet (Viola papilionacea) and creeping Charlie (Glechoma hederacea). Rabbits are abundant. Black legged tick nymphs are active.

Southeast Region (New Bedford)

General Conditions: Busy garden days are here! With 85 growing degree days and over an inch of rain this week, the garden tasks are beginning to pile on. Almost all of our trees and shrubs here in New Bedford have leafed out and many spring flowering trees have burst into blossom with all this rain and a few sunny days. Night temperatures have hovered in the 40’s with Monday evening reaching 38˚F. Day temperatures are in the mid 50’s to low 60’s but continue to feel cool with all the cloud cover. What a treat to see the sun early in the week! Syringa spp. are budding up nicely while early spring blossoms begin to shed.

Pests/Problems: Ticks, black flies, and deer are very active. Lily leaf beetle is out and about. There’s no sign of winter moth on crabapples and blueberries here. Winter die back in the landscape is sticking out like a sore thumb now. Grubs are active in lawns. See the pest section in this message for further details.

North Shore (Beverly)

General Conditions: This reporting period, we experienced cloudy weather and cooler than normal spring temperatures most of the days. Day temperatures were in the low to mid 50s most days except on Tuesday, May 7, when temperatures went up to the low 70s. Night temperatures were mostly in the low to mid 40s. During the first half of this reporting period, we had mostly cloudy and overcast skies, but the last days of the reporting period we have seen some sunny days. We gained 12 growing degree days and 0.56 inches of rainfall at Long Hill in the past week. Due to the continued rains, soils are moist, lawns are green and turf is thriving. Many groups in the area are organizing spring plant sales for the week. Multiple plant species continue to be in full bloom and others are beginning to bloom. Woody plants in full bloom include: mountain Pieris (Pieris floribunda), flowering dogwood (Cornus florida), redbud (Cercis canadensis), large Fothergilla (Fothergilla major), dwarf Fothergilla (Fothergilla gardenii), royal azalea (Rhododendron schlippenbachii), common lilac (Syringa vulgaris), Kwanzan cherry (Prunus serrulata), cucumber tree (Magnolia acuminata), Burkwood Viburnum (Viburnum burkwoodii), cylindrical Magnolia (Magnolia cylindrica), crabapple (Malus spp.) and highbush blueberry (Vaccinium corymbosum). Non-woody plants seen in bloom include: daffodil (Narcissus spp.), forget-me-not (Myosotis sylvatica), tulips (Tulipa sp.), bleeding heart (Dicentra spectabilis), Pachysandra (Pachysandra procumbens), and Vinca vine (Vinca minor).

Pests/Problems: Stem borer damage was observed on some apple trees (round holes on the stem). Anthracnose was observed on flowering dogwood flowers and possible Volutella blight on Pachysandra. Ticks and black flies are active. Weeds seen in bloom include: dandelion (Taraxacum officinale), lesser celandine (Ranunculus ficaria), ground ivy (Glechoma hederacea)and purple deadnettle (Lamium purpureum).

East Region (Boston)

General Conditions: Finally, on May 6 the sun appeared! We reached a high temperature of 76˚F on May 7 and gained 8 GDDs. We had 9.5 GDDs (base of 50˚F) over the past week totaling 110.5 for the year. We continued to add to the precipitation total, gaining 0.4 inches over the past 7 days. The landscape is lush and green as many plants come into bloom adding color. Some plants in bloom include: Amelanchier spp. (serviceberry), Cercis canadensis (redbud), Cercis chinensis (Chinese redbud), Cornus florida (dogwood), Dicentra spectabilis (bleeding heart), Dodecatheon meadia (eastern shooting star), Exocorda x macrantha ‘The Bride’ (pearlbush), Fothergilla gardenii ‘Mt. Airy’, Fothergilla major, Magnolia ‘Elizabeth ‘, Rhododendron vaseyi (pinkshell azalea), Spirea x arguta compacta (dwarf garland Spirea) Spirea x cineria ‘Grefsheim’ (garland Spirea), Viburnum furcatum (forked Viburnum) and Weigela florida (old fashioned Weigela).

Pests/Problems: The addition of sunlight to the adequately moist soils has resulted in the germination of an abundance of weed seeds in mulched beds. Dandelions, ground ivy and violets continue to flower in turf. The difficult to control perennial Convolvulus arvensis (field bindweed) is sprouting from any remnant roots in the soil. Viburnum leaf beetle larvae have emerged. Birch, maple and oak are the main allergens at this time.

Metro West (Acton)

General Conditions: Spring is exploding with the recent spell of summer-like temperatures and April showers. Lawns continue to green up and the mowing crews are out in full force. Precipitation has not yet dropped off, with nearly an inch of rain recorded in this area on six of the past seven days, for a total of 0.82” in this weekly reporting period. The monthly average precipitation for May is 4.04”. The landscape is filled with color and in some stage of bloom at this time are the following woody plants: Amelanchier spp. (shadbush, serviceberry), Cercis canadensis (redbud), Chaenomeles speciosa (common flowering quince), Cornus florida (dogwood), Forsythia spp. (Forsythia), Fothergilla gardenii (dwarf Fothergilla), F. major (large Fothergilla), Halesia carolina ‘Arnold Pink’ (Arnold Pink silverbell), Halesia tetraptera (mountain silverbell), Kerria japonica (Japanese Kerria), Magnolia x loebneri 'Merrill' (Merrill Magnolia), M. x soulangeana (saucer Magnolia), M. 'Butterflies' (butterflies Magnolia), M. 'Yellow Lantern’ (yellow lantern Magnolia), Malus spp. (apple, crabapple), Pieris japonica (Japanese Pieris), Prunus spp. (cherry), including Prunus serrulata 'Kwanzan' (Japanese flowering cherry),and P. japonica (flowering almond), Pyrus spp. (pear), Rhododendron 'P. J. M.' (PJM Rhododendron), R. spp. (early flowering Rhododendron/azalea), Spirea thunbergii (Thunberg Spirea), Syringa spp. (early blooming lilac), Syringa vulgaris (common lilac), Vaccinium angustifolium (lowbush blueberry), V. corymbosum (highbush blueberry), Viburnum 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), Aurinia saxatilis (basket of gold), Brunnera macrophylla (Alkanet), 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 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), Helleborus niger (Christmas rose), Hyacinthus spp. (Hyacinth), Lamium maculatum (dead nettle), Linaria annua (money plant), Mertensia virginica (Virginia bluebells), Muscari sp. (grape Hyacinth), Narcissus spp. (daffodil), Omphalodes verna (blue-eyed Mary), Pachysandra procumbens (Allegheny spurge), P. terminalis (Japanese Pachysandra), Phlox subulata (moss phlox), Polygonatum commutatum (great Solomon’s seal), 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: Ticks and black flies are feeding and active. Winter kill and the resulting brown foliage on many Rhododendrons in this area is now more apparent than ever with its brown contrasting with the lush and colorful landscape. Alliaria petiolata (garlic mustard) continues to bloom and can easily be seen because of its white flowers. It is growing everywhere, including on roadsides and in woodlands, wetlands and gardens. Other weeds seen in bloom now are Glechoma hederacea (ground ivy), Lamium purpureum (purple dead nettle) and Taraxacum officinale (dandelion). Be aware of Toxicodendron radicans (poison ivy); it’s beginning to leaf out so it is fairly easy to detect its shiny red leaves of three.

Central Region (Boylston)

General Conditions: We are now well into that period of spring when the to-do list is three pages long and there are only about half as many hours in the day as needed. Excessive rain continues to be a problem, and waterlogged soils continue to make many gardening tasks difficult. There was an explosion of flowering plants this week. Most tulips are wide open at this point, flowering shrubs like Fothergilla gardenii (dwarf Fothergilla) and Viburnum x burkwoodii (burkwood Viburnum) opened since the last report. Mertensia virginica (Virginia bluebells) and Caltha palustris (marsh marigold) are wide open, as are peaches (Prunus persica) and a crabapple (Malus spp.) here and there. We spotted both orioles and hummingbirds for the first time this week as well. Soil temperatures are finally well above 50˚F in the sun and overnight lows were consistently above 40˚F most of the week.

Pests/Problems: Gypsy moth are definitely out, and so are the mosquitoes. Poison ivy (Toxicodendron radicans) is leafing out and quite attractive this time of year. No other major pest activity at this time.

Pioneer Valley Region (Amherst)

General Conditions: The first week of May in the Pioneer Valley felt a lot like early April with cool temperatures, overcast skies and regular rainfall. Conditions finally improved on Monday, 5/6 when temperatures rose into the middle 70s. The mild weather continued into Tuesday, 5/7 and Wednesday, 5/8 but another dip in temperatures appears to be coming in the long-term forecast. High temperatures over this past reporting period ranged from 54°F to 76°F, while low temperatures spanned from 40°F to 53°F. The cool temperatures in early May really prolonged the flowering period for Bradford pears, serviceberries, Magnolias, Andromeda and cherries. It also slowed new growth on trees and shrubs. But, the gorgeous warm weather from 5/6 – 5/8 allowed woody and herbaceous plants to resume new growth at a steady rate. It hasn’t been a particularly windy spring in the Connecticut Valley but winds did pick up on 5/7 and 5/8 and coupled with the bright sun, caused wilting of some tender landscape plants. It’s amazing how fast the upper soil horizon can dry out at this time of year when the sun is bright, humidity is low and drying winds develop. Therefore, check on recent transplants to ensure the rooting zone has adequate moisture, especially for conifers like arborvitae. We really haven’t had to think about supplemental watering here in the valley for a long time. Rainfall was regular this past week but accumulations were minor in comparison to previous reporting periods. Lawn grasses remain lush and are steadily growing. Ladybugs, lightning bugs, bees, wasps, mosquitoes, black flies and house flies, among other flying insects, are now present on the landscape. With the intensifying sun comes the risk of sunburn. Ensure you either cover up or apply sunscreen if working in exposed settings for prolonged periods. Many sunscreens do actually expire, so check the dates and refresh supplies as needed.

Pests/Problems: First instar gypsy moth caterpillars were observed feeding in Amherst on Japanese elm and apple. Feeding damage was minimal but easy to locate. The breezy conditions on 5/7 and 5/8 were ideal for ballooning caterpillars. Smaller and younger trees can be readily scouted for feeding injury and foliar sprays with Bt are highly effective at this time. Boxwood blight was identified recently on Buxus sempervirens in Hampshire County. The disease results in a rapid shedding of leaves with dark, circular leaf spots and black stem lesions. Because the disease is lethal, removal and destruction of plants is recommended over treatment if boxwoods are small and recently transplanted. Small, green-colored leaf rollers are also abundant on developing foliage on a range of trees. For large and mature trees, the damage is probably trivial but on young and recently transplanted trees, carefully unfurl the curled leaves to find and remove these pests. Grey-colored, flattened fruiting bodies of the wood-rotting fungus Kretzschmaria deusta are very conspicuous on large and old beech trees at this time. The bright white margins of these spore-bearing pads are continuing to thicken and expand. If you enjoy the glossy green foliage of horsechestnut, behold its beauty now. For as the sun will rise, Guignardia leaf blotch will occur on Aesculus. Continue to prune out dead shoot tips and branches as it becomes evident what is dead and what is alive. Trees to pay particular attention to are redbud, Japanese maple and dogwoods. This regular sanitation pruning can help to keep populations of opportunistic stem cankering fungi low.

Berkshire Region (Great Barrington)

General Conditions: Mid-spring weather characterized the arrival of May with sun and warm temperatures on May 6, 7, and 8. Highs on May 6 and 7 reached into the low 70s. The low temperature for the reporting week was 37˚F, recorded on the morning of May 1. Rainfall for the week amounted to 0.73 inches. Though that does not seem like much rain, it was spread out over 5 of the 7 reporting days. Even the sunny days often ended with a brief shower. There was just enough rain and cloud cover to keep soil moisture levels high. Clumping of moist soils could be observed in plowed fields. Because of the high moisture levels, soil compaction and/or formation of ruts remains an issue. Plant development has accelerated with the warmth. Turfgrass has especially been growing very rapidly, necessitating frequent mowing. There is always the temptation in such situations to cut grass low but doing so will slow root development and potentially result in stressed turf when dry conditions occur.

Pests/Problems: The newest pest observed this week was Viburnum leaf beetle. The tiny larvae of the beetle can now be seen – with the aid of a hand lens – on the undersides of leaves of Viburnum. Viburnum sargentii and V. dentata are currently hosting the pest. Cutworms were also observed for the first time this spring. Boxwood leaf miner is still in its larval stage. Eastern tent caterpillars are about a half-inch in length and feeding on foliage of crabapples. Also active are spruce spider mites. Examples of winter injury to needled evergreens, boxwoods, and Rhododendrons can be seen throughout the county. Many plants have been damaged to the point where severe pruning or removal from the managed landscape is necessary. Also, some earlier frost damage can be seen on some of the yellow-flowering cultivars of Magnolia. The damage is confined to the tips of flower petals. Black flies made an appearance this week and join other nuisance critters including deer ticks, mosquitoes, and wasps.

Regional Scouting Credits

• CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
• SOUTHEAST REGION - Kristin McCullin, Horticulturist reporting from Haskell Public Gardens, New Bedford.
• 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 UMass Amherst.
• BERKSHIRE REGION - Ron Kujawski, Horticultural Consultant, reporting from Great Barrington.

Woody Ornamentals

Diseases

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

Boxwood blight, caused by Calonectria pseudonaviculata, on common boxwood (Buxus sempervirens). Several plants in a residential landscape are infected with the destructive disease. The shrubs are three- to five-years-old and were planted in spring of 2018. Darkened, circular leaf spots, black stem lesions and excessive leaf shedding were observed this spring. Calonectria was readily sporulating from submitted stems and foliage (see photo). The plants were transplanted into a full sun setting with drip irrigation and appeared healthy last fall. In addition to boxwood blight, Volutella blight, Macrophoma leaf spot and boxwood spider mite were also located. Given the size and time since transplanting, removal and destruction is the clear choice for appropriate management.

Transplant shock, winter injury and needle blight caused by Pestalotiopsis on Green Giant arborvitae (Thuja standishii × plicata 'Green Giant'). Three trees, approximately five-years-old, were transplanted in 2018 into a residential garden. The trees get a mix of sun and shade and were supplied supplemental water via drip irrigation. This spring, two of the trees exhibited severe needle browning throughout the canopy while the third tree had only minor injury. The injured trees will likely require removal given the extent of the injury. Needles were pale brown and desiccated. For a rapidly-growing, dense screen, Green Giant arborvitae is a good choice. However, these trees seem to experience winter burn and transplant shock at a higher rate than northern white cedar (T. occidentalis).

Needle blight on Japanese black pine (Pinus thunbergii) caused by Phomopsis and Septorioides strobi. The tree is roughly 15-years-old and was planted 11 years ago at the site. Conditions at the site include full sun with moderately well-drained soils. This spring, a large volume of browning needles were observed in the canopy. Increasingly, Septorioides can be found causing needle blight on hard pines in the region. The fungus was only first described in 2015 and has been a primary contributor to the needle blight epidemic impacting eastern white pine needle. Phomopsis is not often found as a needle blight pathogen on conifers but was abundant on the submitted sample. Its presence is not altogether surprising, given the dynamic nature of this fungal pathogen.

Needle and stem blight caused by Diplodia sapinea on Korean pine (Pinus koraiensis). The tree is approximately 30-years-old and has been present at the site since 1990. The arboretum setting offers full sun but the clay soils where the tree resides are wet and compacted. This spring, extreme canopy dieback was observed with a near complete defoliation of the lower canopy. The tree may have been exposed to herbicides, which could have predisposed it to attack from Diplodia. The fungus was abundant on submitted stems and needles. While two- and three-needle pines are preferred, Diplodia can be readily found on five-needle pines.

Winter injury and Phyllosticta leaf blotch on catawba Rhododendron (Rhododendron catawbiense). The shrub is approximately 15-years-old and has been present at the site for 10 years. Severe leaf browning and canopy dieback was observed in early April and the plant has been robust and healthy in years past. Phyllosticta was present in blighted sections of the submitted foliage (see photo). This opportunistic pathogen is common on Rhododendron but thrives when plants suffer from cold injury. The woodland garden setting offers sun and shade.

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

Insects

Happy 2019 Growing Season!

It’s good to be back! On a personal note, this particular UMass Entomology Specialist has returned (this very week) from maternity leave. Our son Marshall was born on January 24, 2019. He has already helped me scout for gypsy moth caterpillars – perhaps we have a budding entomologist on our hands!

I make this note because there is a lot of catching up to do with pest activity for the 2019 season during my brief winter/spring absence. Most notably, below you will see pertinent updates for winter moth, gypsy moth, emerald ash borer, and the spotted lanternfly. Another area to highlight would be the information provided regarding ticks, particularly FREE recorded webinars that are now available through the TickTalk Webinar Series with TickReport and the UMass Laboratory of Medical Zoology.

I want to thank my colleagues who continued to get some insect information out in the Landscape Message “Insects” section during my absence. I also want to wish all of our readers a fantastic 2019 growing season! Happy scouting!

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

• Gypsy Moth: (Lymantria dispar) host plants include but are certainly not limited to oak (favored), maple, birch, poplar, and many others. Gypsy moth egg hatch is under way in Massachusetts for the 2019 season. Professionals working in Millis, MA reported gypsy moth egg hatch (with photo evidence) on 4/23/19. Elizabeth Garofalo, Integrated Pest Management Specialist with UMass Extension’s Fruit Program, observed gypsy moth egg hatch in Belchertown, MA (Hampshire County) on 4/23, 4/25, 5/2 and 5/6/2019 as reported in “Hawkeye’s Corner” of the Healthy Fruit Newsletter, available here: https://ag.umass.edu/fruit/publications/healthy-fruit . Professionals, Extension educators, and state collaborators have also reported gypsy moth egg hatch occurring in Barre, MA on 5/3/19 (Worcester County), Hubbardston, MA on 5/6/19 (Worcester County), Shrewsbury, MA on 5/6/19 (Worcester County), and Leicester, MA in the village of Rochdale on 5/7/19 (Worcester County). Some ballooning has been observed in Belchertown and Amherst, MA as of this week, yet reports in central MA indicate that in certain areas, caterpillars are still actively hatching from their egg masses. Gypsy moth eggs do not all hatch at once, so ballooning can occur over a period of days/weeks depending upon the location and weather conditions, just as hatch can. Therefore, keep an eye on local egg masses and the new leaves of favored host plants for emerging, dispersing, and feeding caterpillars. Timing management options, such as applications of Bacillus thuringiensis kurstaki (Btk), may be prudent once more caterpillars balloon and settle to feed on valuable hosts in the landscape. (Although reaching every caterpillar will be difficult because they do not all do this at exactly the same time.) Remember, Btk must be ingested by the caterpillars to be effective, and it is best used on young, more vulnerable gypsy moth caterpillars roughly ¾ inch in length or smaller.

Ballooning occurs when very young caterpillars spin a silken thread and catch the wind to blow onto a new host plant once the thread breaks. This method of dispersal can lead to host plants becoming defoliated that previously did not have egg masses directly on them. Egg masses may be present on nearby oaks, for example, and provide a local population of caterpillars.

Despite the fungal outbreak that swept through the 2017 caterpillar population, some lucky caterpillars survived to pupation and emerged as adult moths. (However, adults were present in 2017 in far fewer numbers than would have existed without the fungus.) In 2018, the Massachusetts Department of Conservation and Recreation (DCR) reported that approximately 159,705 acres were defoliated by gypsy moth caterpillars in pockets across the state. While this may seem negligible in comparison to the 923,186 acres of defoliation due to gypsy moth in 2017, for many communities the impact was still significant. MA DCR also surveyed multiple locations across the state for overwintering gypsy moth egg masses in December of 2018. They provide a map of their predictions of where pockets of defoliation may occur in 2019 based on the densities of egg masses they observed in monitored areas across the state. Many of these areas correspond with the locations previously defoliated by gypsy moth caterpillars in 2018. MA DCR predicts gypsy moth activity will occur in regionalized pockets of Essex, Hampden, Hampshire, Middlesex, Norfolk, Plymouth, and Worcester Counties. Maps of previous year’s defoliation as well as the 2018 overwintering gypsy moth egg mass survey may be found courtesy of the MA DCR here: https://www.mass.gov/guides/gypsy-moth-in-massachusetts .

While it is very difficult to predict how much defoliation Massachusetts will see in 2019 due to gypsy moth caterpillar feeding, we can be certain that in areas where many egg masses have overwintered, pockets of defoliation could still occur in certain areas of the state this year.

• Winter Moth: (Operophtera brumata) The winter moth population in eastern Massachusetts continues to be at a record low and Dr. Joseph Elkinton, Professor of Environmental Conservation at the University of Massachusetts is declaring victory over this pest! In case you have missed this news from last year, a recent edition of the UMass Magazine discusses the winter moth story and successes with the biological control of this insect (along with some fun and excellent illustrations): https://www.umass.edu/magazine/spring-2019/winter-moth .

Winter moth caterpillars were reported on 4/19/19 in apple buds on the upper Cape and on 4/26/19 in Barnstable, MA in susceptible hosts. See the Cape Cod Regional Report above for current updates. Heather Faubert of the University of Rhode Island Cooperative Extension reported fewer winter moth eggs on trees monitored in Franklin, MA this spring and reported winter moth egg hatch beginning around April 10, 2019 at sites monitored in Franklin, MA and locations in Rhode Island.

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 .

• 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 .

• Balsam Twig Aphid: Mindarus abietinus is active between 30-100 GDD’s, base 50°F. Inspect the needles of balsam fir, Fraser fir, and other true firs for “stem mothers” that will soon be reproducing. Young aphid feeding will lead to distorted foliage. (Needles curl.) Excessive amounts of honeydew are produced and cause needles to stick together. Monitor for the presence of reproducing females and treat with an oil application as weather permits, according to label instructions.
• Deer Tick/Blacklegged Tick: Check out the archived FREE TickTalk with TickReport webinars available here: https://ag.umass.edu/landscape/education-events/webinars. The next live webinar will be held on October 9, 2019 with Dr. Stephen Rich of the UMass Laboratory of Medical Zoology. Previous webinars include information about deer ticks and associated diseases, ticks and personal protection, and updates from the Laboratory of Medical Zoology.

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 at this time, and may be encountered at this time, through August. 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 on springtime cleanup and planting 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.

• Eastern Spruce Gall Adelgid: Adelges abietis is a pest of Norway spruce primarily, but occasionally damages other spruce species. This adelgid overwinters as a partially grown female, often referred to as a stem mother. These overwintering individuals mature 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.

• Eastern Tent Caterpillar: Malacosoma americanum eggs have hatched. Eastern tent caterpillars are reported this week in the Berkshire Regional Report (above). Likely eastern tent caterpillar eggs have hatched anywhere they exist in the state at this time. Susceptible hosts include cherry and crabapple. Other host plants whose leaves are fed upon by this native insect can include apple, ash, birch, willow, maple, oak, poplar, and witch-hazel. Eastern tent caterpillars are native to Massachusetts and have many associated natural enemies (parasites and predators) that help regulate populations. Unless these caterpillars are actively defoliating specimen trees in a landscaped setting, we can coexist with this particular herbivore native to our forests.

• Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. Crawlers will be present this month and throughout the growing season and the overlap of many developmental stages at any given time can be observed. 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.
• Emerald Ash Borer: (Agrilus planipennis, EAB) Since the New Year, the Massachusetts Department of Conservation and Recreation has confirmed 26 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 Berkshire, Hampden, Hampshire, Middlesex, and Worcester 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, 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 .

• European Pine Sawfly: Neodiprion sertifer caterpillars are 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 pines. It is also found on white, Austrian, ponderosa, shortleaf, and pitch pine when near the aforementioned species. This dark colored caterpillar feeds in tight groups so small numbers can be pruned or plucked out of host plants and destroyed. Larger numbers can be treated with an insecticidal soap spray when the caterpillars are still small. 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.

• Forest Tent Caterpillar: Malacosoma disstria egg hatch occurs between 192-363 GDD’s, base 50°F, which typically coincides with sugar maple bud break. Susceptible hosts whose leaves are fed on by this insect include oak, birch, ash, maple, elm, poplar, and basswood.

• 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. Monitor susceptible hosts for small, inch-worm like caterpillars. Where populations are low, no management is necessary.

• Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. Infested trees may be treated with foliar sprays in late April to early May, using Japanese quince as a phenological indicator. Look for the females, covered in a white, woolly, waxy material and settled at the base of hemlock needles.

• Imported Willow Leaf Beetle: Plagiodera versicolora adult beetles overwinter near susceptible hosts. Adult beetles will chew holes and notches in the leaves of willow. Adult beetles mate and lay eggs through the end of this month. 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.

• Lily Leaf Beetle: Lilioceris lilii overwintering adults have been reported by scouts in the Southeast Region (see above). Adults overwintered in sheltered places and are now active with warm temperatures and available food sources. 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.

• Snowball Aphid: Neoceruraphis viburnicola 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, officials with the Massachusetts Department of Agricultural Resources (MDAR) have urged residents to check plants for spotted lanternfly. On February 21, 2019 MDAR announced the discovery of a single dead spotted lanternfly adult at a private residence in Boston. As a result of this discovery, officials asked the public to check potted plants they purchase and report any suspicious insects. MDAR reports that this particular individual appeared to have been unintentionally transported this past December in a shipment of poinsettia plants originating from Pennsylvania. Officials also report that there is currently no evidence that this pest has become established in MA. For more information about this finding, please visit the MA Department of Agricultural Resources press release: 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 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 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. 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. See regional reports above (such as the Berkshire Region) for current activity.

• 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 egg hatch has been reported in the regional reports above (see: Berkshire Region and East Region). Tiny leaf beetle larvae can be seen feeding on the undersides of foliage at this time. 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. Larvae, when they are present, may be treated with a product containing spinosad once they appear. 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 Spotted Pine Sawyer (WSPS): Monochamus scutellatus will be pupating this month and 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.

• 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

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