Landscape Message: September 22, 2017

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 September 20. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2017 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 (2-Week Gain)	Time/Date of Readings
	2-Week Gain	2017 Total	Sun	Shade
Cape Cod	238	2298	68	67	3.65	12:00 PM 9/20
Southeast	n/a	n/a	n/a	n/a	n/a	n/a
North Shore	251	2353	65	63	0.26	9:30 AM 9/21
East	249	2567.5	69	66	3.00	3:00 PM 9/20
Metro West	209	2283	65	63	1.64	5:45 AM 9/20
Central	197	2297	70	70	1.64	3:23 PM 9/20
Pioneer Valley	239	2385	70	67	0.30	11:00 AM 9/20
Berkshires	237	2083	67	63	0.89	9:30 AM 9/20
AVERAGE	231	2324	68	66	1.63	-
n/a = information not available

Drought Status: Approximately 80% of Massachusetts is not under official drought status at this time.  The 20% classified as 'Abnormally Dry' includes the northernmost portions of Essex county, virtually all of Plymouth and Bristol counties, and the southern 2/3rds of Norfolk county.  For more information see http://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.
Heptacodium miconioides (Seven-Son Flower)	Full	*	*	Full	Full	Full	Full	*
Clematis paniculata (Sweet Autumn Clematis)	Full	*	*	Full	Full	Full	Full	Full
Polygonum cuspidatum (Japanese Knotweed)	Full/End	*	*	Full	Full/End	*	Full	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature from September 6 - September 20 was 66° F with a high of 80° F on September 12 and a low of 51° F on September 10. The period has been up and down in temperature and is ending with several days of humid, cloudy, foggy weather. 3.65 inches of precipitation fell in Barnstable during the period with most of the rain occurring on September 6 & 7, totaling just over 3.0 inches. Currently (September 20) conditions are rainy and breezy as a result of the tropical disturbance Jose. Topsoil and subsoil moisture levels are adequate.

Pests/Problems: Insect pests or damage seen during the period include viburnum leaf beetle damage on V. dentatum including egg laying sites, two spotted spider mite damage on hydrangea, chilli thrips on hydrangea, azalea lace bug on PJM rhododendron, andromeda lacebug on andromeda, sycamore lacebug on sycamore, hibiscus sawfly on hibiscus, and turpentine beetle damage on pitch pine. Diseases or disease damage over the period include foliar nematodes on Japanese anemone, leaf spot on Tilia americana, Hydrangea rust on H. arborescens, Guignardia leaf blotch on horsechestnut, Volutella blight on boxwood, armillaria on Caryopteris, tar spot on maple, and powdery mildew on lilac, Monarda, rose, coreopsis, phlox, dogwood, white oak, and sycamore. Weeds in bloom include prostrate spurge (Euphorbia maculata), Pennsylvania smartweed (Polygonum lanceolata), spotted knapweed (Centaurea maculosa), Japanese knotweed (Polygonum cuspidatum), redroot pigweed (Amaranthus retroflexus), ragweed (Ambrosia artemisiifolia), crabgrass (Digitaria spp.), horseweed (Conyza canadensis, and mugwort (Artemisia vulgaris).

Southeast Region (Hanson)

No report available this week.

North Shore (Beverly)

General Conditions: Average daily temperatures during this reporting period were in the low to high 70s during the day and low 50s to low 60s during the night. Temperatures of 80 degrees and above were recorded for only two days. Long Hill gained 251 growing degree-days during this two-week period, and light rainfall occurred on several days. The effect of tropical storm Jose was felt on September 20 with average wind speeds of 15 mph and rain showers throughout the day. The total amount of precipitation received was 0.25 inches. Woody plants seen in bloom include: Seven-son flower (Heptacodium miconioides), Chaste tree (Vitex agnus-castus), Bush clover (Lespedeza thunbergii), Herbaceous plants seen in bloom include: New England aster (Symphyotrichum novae-angliae), Garden phlox (Phlox paniculata), hostas (Hosta spp.), Autumn joy sedums (Sedum spp.), Rudbeckia (Rudbeckia hirta), Coneflower (Echinacea purpurea), Morning glory (Ipomoea purpurea), Japanese anemone (Anemone x hybrida), Hardy Begonia (Begonia grandis), Corydalis (Corydalis lutea) and Autumn Crocus (Colchicum autumnale). Different kinds of annuals are also contributing color in landscapes.

Pests/Problems: Powdery mildew continues to be observed on some lilac varieties and on garden phlox. Anthracnose was also observed on Peony. Tar spot and anthracnose are prevalent on maple trees. Crabgrass and other weeds such as, horseweed (Conyza canadensis), ragweed (Ambrosia artemisiifolia) and Japanese knotweed (Polygonum cuspidatum) are thriving in the landscape. Goldenrod (Solidago canadensis) continues to be in full bloom and is still providing a lot of color on roadsides. Mosquitoes have slowed down but they are still active at dawn and dusk. Ticks are still very active

East Region (Boston)

General Conditions: Conditions have varied over the last two weeks; we saw seasonal temperatures from the 6^th to the 10^th before hot and humid conditions returned from the 11^th to the 17^th, more reminiscent of summer weather. Fog in the early morning of the 17^th was followed by cloudy, cool and rainy conditions on the 18^th as Hurricane Jose approached, although the storm remains off shore, we continue to experience stormy conditions as of the 20^th. High temperatures have ranged from 66° F to 85° F averaging 77° F, while lows have ranged from 50° F to 67° F averaging 58°F. Unsettled systems from the 14^th through the 18^th brought thunderstorms, and downpours with a constant possibility of pop-up showers, though often they did not materialize. We received considerable precipitation; one inch fell on the 6^th/7^th, while the remainder fell from the 14^th to the 20^th. In total, we received a much welcome 3.0 inches of rain. Some fall flowering plants in bloom include: Echinacea purpurea (coneflower), Eurybia divaricata (white wood aster), Eutrochium purpureum (Joe Pye weed), Hosta sp. (hosta), Perovskia atriplicifolia (Russian sage), Rosa 'Carefree Beauty’ (Carefree Beauty rose), Sedum ‘Autumn Joy’, Sedum sp. (many sedum and stonecrop and their cultivars), many Solidago sp. (goldenrod), Symphyotrichum novae-angliae (New England aster), and Weigela sp. (weigela). Fall colour is beginning to show on Phellodendron amurense (Amur cork tree), some Acer sp. (maples), and many stressed trees.

Pests/Problems: Cloudy, rainy conditions were welcomed for fall planting. Supplemental irrigation has eased up this week due to the three inches of rain we have received. Despite this, some soils remain dusty and dry. Weeds releasing seed include: Ambrosia artemisiifolia (annual ragweed), Cynanchum louiseae (black swallow-wort), Digitaria sp. (crabgrass), Erigeron canadensis (horseweed), Euphorbia maculata (spotted spurge), Phytolacca americana (pokeweed). Bidens frondosa (Devil's beggar-ticks) is getting very close to spreading seed. Tar spot on maples including Acer platanoides (Norway maple) is evident throughout the landscape and is causing pre-mature leaf drop. Guignardia leaf blotch on Aesculus sp. (horsechestnut) is very apparent and has caused complete defoliation of Aeculus hippocastanum (European horsechestnut). Dogwood sawfly (Macremphytus tarsatus) continues to defoliate red osier dogwood (Cornus sericea). Viburnum leaf beetle (Pyrrhalta viburni) egg masses are present on native viburnums.

Metro West (Acton)

General Conditions: It’s the calm before the storm. Tropical Storm Jose is making its way up the coast and is threatening this area with showers to heavy rain, wind gusts as high as 21 mph and patchy fog. If nothing else, let’s just hope that we receive some steady rain out of this storm since rainfall has been minimal for the month so far. September’s average rainfall is 3.77” and a total of 2.15” has been recorded for the month so far. The fall equinox is fast approaching and yet it still feels like summer! The hot, humid and dry weather continued into September.

Woody plants seen in bloom this past couple of weeks include: Buddleia spp. (Butterfly Bush), Franklinia alatahama (Franklin Tree), Heptacodium miconioides (Seven-Son Flower), Hibiscus syriacus (Rose-of-Sharon), Hydrangea paniculata (Panicle Hydrangea), and its many cultivars including 'Tardiva', Potentilla fruiticosa (Potentilla), and Rosa 'Knockout' (The Knockout family of Roses). A woody vine in bloom is Clematis paniculata (Sweet Autumn Clematis). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Aster spp. (New England Aster, New York Aster, Smoother Aster, White Wood Aster), Boltonia asteroides (Bolton’s Aster), Chelone lyonii (Pink Turtlehead), Echinacea purpurea (Coneflower), Eutrochium purpureum (Joe Pye Weed), Hosta spp. (Plantain Lily), Kirengeshoma palmata (Yellow Wax Bells), Patrinia gibbosa (Patrinia), Perovskia atriplicifolia (Russian Sage), Phlox carolina (Carolina Phlox), P. paniculata (Garden Phlox), Rudbeckia fulgida var. sullivantii 'Goldsturm' (Black-eyed Susan), Sedum ‘Autum Joy’, S. ‘Rosy Glow’ (Stonecrops), and Solidago spp. (Goldenrod)and the colorful fruit on Cornus (Dogwood), Malus (Crabapple), and Viburnum.

Pests/Problems: Let’s hope that we receive more rain now that the fall planting season is upon us. Observed in the landscape these past two weeks were browning and leaf drop on Acer platanoides (Norway Maple) due to tar spot and/or anthracnose, leaf blotch on Aesculus sp. (Horsechestnut), powdery mildew on Hamamelis (Witch Hazel), Monarda (Bee Balm), Phlox, and Syringa (Lilac), and Cedar Apple Rust on Amelanchier sp. (Serviceberry).

Central Region (Boylston)

General Conditions: Autumn foliage hues are now quite evident in wet, low-lying areas and on plants that are under stress. The heavy fruit set on winterberry promises to create a show once foliage has dropped. Annuals and tender perennials are lush and colorful, and vegetables remain productive. Hydrangea paniculata cultivars continue to bloom. Anemone tomentosa ‘Robustissima’, Calamintha sp., Clerodendron trichotomum, and Kirengeshoma palmata are among the hardy plants continuing to provide color. Knockout Roses are reblooming. Recent rains are keeping turf and plantings lush.

Pests/Problems: Still seeing Dogwood Sawfly, and now Birch Sawfly. Powdery mildew is evident. Woodchucks, rabbits and deer remain abundant and damaging

Pioneer Valley Region (Amherst)

General Conditions: Summer has returned to the Pioneer Valley as the autumnal equinox arrives and we officially transition towards the dormant season. After a promising start to the month, with significant rainfall over the Labor Day weekend, conditions have been dry for over two weeks now. High temperatures have been mild (middle 70s) to warm (middle to upper 80s), but since 9/14 dew points have been high, creating muggy and hazy conditions that have persisted since. Surface soils are dry but turfgrasses and weeds continue to flourish with the generally cooler temperatures. Soil temperatures actually increased slightly since the last report, indicative of the warm nights and lack of precipitation. Trees are beginning to senesce and we have essentially crossed the threshold for what is considered “early leaf drop”. From late September onward, senescence and leaf drop for most trees and shrubs can be considered normal. Hydrangeas continue to provide color as the petals transition from white to pink, while asters, goldenrod and other native flowering plants are abundant this season. Crickets and grasshoppers, among other insects have been very active attracting mates, seemingly more so this year than in previous years. Their day and nighttime chorus is one of the best features of late summer, especially near large meadows and fields.

Pests/Problems: Continue to water recent transplants, especially given the lack of precipitation since Labor Day and the high humidity over the past week. White pines and arborvitae are senescing older needles, which is sometimes confused with disease or insect problems. Conifers transplanted this season will shed larger than average volumes of needles due to transplant shock, so reassure clients that this is normal and does not mean the trees are dying. Scattered sugar maples are browning and will not be producing their normal brilliant fall color. In some cases, this is due to maple anthracnose, which has been widespread and destructive this season. Several different fungi are responsible for maple anthracnose, which is initiated by abundant early season rainfall. These pathogens often go dormant during the heat of summer and then re-emerge in autumn to cause further problems. Leaf drop of crabapple and apple continues, due largely to anthracnose, apple scab and marssonina leaf blotch. As expected, it was a big year for lacebugs on azalea, rhododendron, Andromeda and, in some cases, serviceberry.

Berkshire Region (Great Barrington)

General Conditions: The erratic weather pattern this summer continues. After two weeks of much cooler than normal temperatures – and even a light frost on Sept. 2^nd - the pattern has changed. Since Wednesday, Sept. 13, temperatures have steadily risen to well above normal while humidity levels also increased. Day time levels were in the low 80s on Sept. 16, 17, 18. Night time temperatures likewise were well above normal, in the low to mid 60s compared to the norm for this time of year of upper 40s. The unseasonably warm and humid conditions are expected to continue for another week or so. Just as the weather has been somewhat odd, so has plant development. Since spring, plant development has lagged somewhat, yet we are now seeing considerable amount of pre-mature fall foliage color. For example, the foliage of some red maples (Acer rubrum) has completely changed to its fall color. Likewise, many burning bush (Euonymus alatus) have taken on their fall color more than a week ago. Rainfall during the past two weeks has been light and, combined with the unseasonably warm weather, soil moisture levels are low. Unless, the remnants of recent and future hurricanes deposit any precipitation in the far reaches of western Massachusetts, irrigation is advisable for woody and herbaceous perennial species, especially any which were or are to be planted this month. Turfgrass is growing well though not quite as rapidly as in July and August when rains were more frequent.

Pests/Problems: The most annoying pests at this time are the numerous gnats which fly into your face and eyes. Wasps and hornets are more aggressive as well. Anyone dining outdoors or imbibing in sugary drinks need to be particularly cautious since these stinging insects have shifted their diet away from high protein foods, such as caterpillars, to high carbohydrate foods, i.e. nectars and people drinks. Among the plant pests are magnolia scale and euonymus scale, both of which are in their crawler stage and vulnerable to insecticidal sprays, including insecticidal soap and neem oil. Aphid activity continues on tulip trees (Liriodendron tulipifera) and some blackening of leaves due to sooty mold is evident. A curiosity was an incredibly dense infestation of aphids on a Korean fir (Abies koreana) at the Berkshire Botanical Garden in Stockbridge. They are most likely bow-legged fir aphids (Cinara curvipes), recognizable by their relatively large size and shiny black color. Unlike many aphid species which feed on foliage and/or herbaceous stems, these aphids feed on the twigs and branches of their host trees. Two-spotted spider mites and tussock moth caterpillars continue to be found in the landscape.

The prevalence of foliar diseases this growing season is largely responsible for much of the early leaf drop which can be seen throughout the region. Many trees and shrub specimens, mostly crabapples, chestnuts, ash, honey locust, and hawthorns, are now completely defoliated. Likewise, many herbaceous plants are pre-maturely ravaged by an assortment of foliar diseases. As always, fall clean-up of diseased foliage is the first step in prevention of infections next growing season. In perennial flower borders, attention should be given to plant division and thinning to improve air flow around plants.

Regional Scouting Credits

• CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
• SOUTHEAST REGION - Deborah Swanson, UMass Extension Horticulturist for Plymouth County - Retired, reporting from Hanson.
• 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 Arnold Arboretum, Jamaica Plain.
• METRO WEST REGION – Julie Coop, Forester, Massachusetts Department of Conservation & Recreation, reporting from Acton.
• CENTRAL REGION  -  Joann Vieira, Superintendent of Horticulture, reporting from the Tower Hill Botanic Garden, Boylston.
• PIONEER VALLEY REGION - Kelly Allen for 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:

Severe infestation of the spruce spider mite (Oligonychus ununguis) on Austrian pine (Pinus nigra). Two bonsai trees that are between 20 and 30-years-old, present at the current location for just one year, and repotted three months ago. The canopies have an overall chlorotic appearance and upon microscopic evaluation, needles exhibited flecking symptoms and there were abundant cast skins and egg sacs. Predatory mites were being used to combat the problem. The spruce spider mite attacks a broad array of conifers, resulting in serious damage to infested needles if the infestations are not caught early.

Fire blight, caused by Erwinia amylovora, on ornamental cherry (Prunus sp.). Tree is 15-years-old, resides in a partially shaded setting and does not receive supplemental irrigation. While nearly all rosaceous hosts are susceptible to fire blight, landscape infections of cherry are uncommon. Symptoms were not as distinctive on this sample, compared to what is normally observed on apple/crabapple and pear. Leaves were browning and prematurely shedding and shoot tips were blackened but not curled at the tips.

Needle browning and canopy dieback of Hollywood juniper (Juniperus chinensis ′Torulosa′). 12 trees planted in a screening row, between 6–7′ tall and planted in June of 2014. Needle browning and dieback was evident in previous years on a few of the trees, but worsened in 2017 and symptoms are now present on all 12 plants. There was a moderate infestation of the juniper scale (Carulaspis juniperi), a minor infestation of the spruce spider mite (Oligonychus ununguis) and needle and shoot blight from Pestalotiopsis. The trees receive approximately 60% sun and have been provided with supplemental water. Soils are sandy and well-drained. While more than half-sun is sufficient for many conifers, it may not be quite enough for a Juniperus, which prefer full sun settings.

Viburnum downy mildew, caused by Plasmopara viburni, on arrowwood viburnum (Viburnum dentatum). Numerous one-year-old plants in a nursery setting developed symptoms of the disease (chlorotic to brown spots, marginal leaf burn and premature leaf shedding) within the past few weeks. The pathogen was sporulating in abundance on the underside of the foliage, which was readily visible with the naked eye. Downy mildews derive their name from the tufted masses of gray-colored, spore-bearing structures that from on infected plant parts. They are not particularly destructive to woody plants, being more problematic on vegetable crops in the region. However, on select hosts, such as viburnum, downy mildew can be an important late season disease. Plasmopara viburni, like all downy mildew pathogens, thrives under humid conditions and is biotrophic, meaning it can only survive in a living host.

Stem cankering, caused by Diplodia cupressi, and needle blight, caused by Pestalotiopsis, on Leyland cypress (×Cupressocyparis leylandii). Tree is 20-years-old, resides in a full sun setting in moderately well-drained soils and has been present at the site for many years. Lawn irrigation may provide some supplemental water. Over the past several years, the tree has exhibited scattered branch wilting, with affected needles progressing in color from orange to brown and finally gray. Stems infected with D. cupressi appear reddish-brown and may have sap extruding from splitting cankers.

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

Insects

Photo-worthy insects and insect feeding, because not all insects we see in our landscapes are pests:

• Leafcutter Bee Evidence: Evidence of leafcutter bee activity was observed on 9/20/17 in Amherst, MA on eastern redbud (Cercis canadensis). Some of the most common leafcutter bees belong to the genus Megachile. These bees look similar to bumble bees, except they may be smaller with rows of white hair on the abdomen. These species of bee are solitary, meaning that each female tends her own nest (does not live in a social hive arrangement). The bees cut disks from certain plant leaves, which they then use to line and plug up cells used for their eggs. Each bee can make multiple cells for this purpose in hollow stems, twigs, and other protected areas. These bees are native to the United States and can be important pollinators. Although they may cut circular disks from the leaves of roses, azaleas, ash, redbud, and other ornamental plants, the damage they cause is negligible and does not impact overall plant health.

• Orange Dog/Giant Swallowtail: The caterpillar stage ofPapilio cresphontes is certainly photo-worthy. This insect is widely distributed throughout the United States and much of North, Central, and South America. Host plants include members of the Rutaceae, the citrus family, including but not limited to prickly ash (Zanthoxylum spp.), torchwood (Amyris spp.), and hoptree/wafer ash (Ptelea trifoliata). The two caterpillars pictured here were collected from wafer ash on 9/21/17 in Amherst, MA. These caterpillars may partially defoliate small, potted plants but are otherwise not problematic. They may be considered minor pests in certain Citrus spp. crops. The adult butterflies of this species will sip nectar from flowering plants such as azalea, Japanese honeysuckle, goldenrod, and swamp milkweed but can be common to many flowering plants. The adult butterfly is quite the attractive swallowtail, however these caterpillars can be appreciated as well. The orange dog caterpillars (or orange puppy depending on who you ask) possess iridescent sapphire-blue spots and defense-related patterns: bird dropping-like markings coupled with what some call snake-mimicry. Scale-like markings, like those of a snake, can be seen on more mature caterpillars, near the thorax. But perhaps the most impressive defense mechanism of all is the bright red osmeterium that the caterpillar will exude when irritated. This structure may look like the forked tongue of a snake, but it is a gland that contains a mixture of chemicals that produce a putrid smell. This pungent aroma has been described by some as similar to that of “rancid butter”. The aroma is certainly unpleasant and surprisingly strong.

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

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

The regulated area for Asian longhorned beetle is 110 miles² encompassing Worcester, Shrewsbury, Boylston, West Boylston, and parts of Holden and Auburn. If you believe you have seen damage caused by this insect, such as exit holes or egg sites, on susceptible host trees like maple, or have captured an adult beetle that you believe to be ALB, 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.

• Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. Crawlers will be present throughout the growing season and the overlap of many developmental stages at any given time can be observed.

• Emerald Ash Borer (EAB): A new county detection of Agrilus planipennis (EAB) was made using green panel traps and a combination of a host plant volatile chemical and pheromone (sexual attractant) lures placed in Brookline, MA. This is unfortunately a new county detection (Norfolk County) in Massachusetts for 2017. (However, it is in very close proximity to a prior detection made in Suffolk County.) EAB has previously been detected in Berkshire County (2012), Essex County (2013), Suffolk County (2014), Worcester County (2015), and Hampden County (2016). In this case, two green panel traps, hung in close proximity to one another, captured 6 adult beetles between them, which were collected on 7/14/17 and sent to the UMass Plant Diagnostic Laboratory for confirmation. This identification was also confirmed by the USDA Animal and Plant Health Inspection Service (APHIS).

EAB readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus) and most recently, cultivated olive (Olea europaea). (See: https://academic.oup.com/jee/article-lookup/doi/10.1093/jee/tox139) Signs of an EAB infested tree may include D-shaped exit holes in the bark, “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/upon peeling 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 a map of the known locations of emerald ash borer in the state, as well as 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 it at the Massachusetts Introduced Pests Outreach Project: http://massnrc.org/pests/pestreports.htm.

• Fall Home-Invading Insects: Various insects, such as ladybugs, boxelder bugs, seed bugs, and stink bugs have begun to seek overwintering shelters in warm places, such as homes. While such invaders do not cause any measurable structural damage, they can become a nuisance especially when they are present in large numbers. If you are not willing to share your home with such insects, now should be the time to repair torn window screens, repair gaps around windows and doors, and sure up any other gaps through which they might enter the home.

• Fall Webworm: Hyphantria cunea is native to North America and Mexico. It is now considered a world-wide pest, as it has spread throughout much of Europe and Asia. (For example, it was introduced accidentally into Hungary from North America in the 1940’s.) Hosts include nearly all shade, fruit, and ornamental trees except conifers. In the USA, at least 88 species of trees are hosts for these insects, while in Europe at least 230 species are impacted. In the past history of this pest, it was once thought that the fall webworm was actually two species. It is now thought that H. cunea has two color morphs – one black headed and one red headed. These two color forms differ not only in the coloration of the caterpillars and the adults, but also in their behaviors. Caterpillars may go through at least 11 molts, each stage occurring within a silken web they produce over the host. When alarmed, all caterpillars in the group will move in unison in jerking motions that may be a mechanism for self-defense. Depending upon the location and climate, 1-4 generations of fall webworm can occur per year. Fall webworm adult moths lay eggs on the underside of the leaves of host plants in the spring. These eggs hatch in late June or July depending on climate. Young larvae feed together in groups on the undersides of leaves, first skeletonizing the leaf and then enveloping other leaves and eventually entire branches within their webs. Webs are typically found on the terminal ends of branches. All caterpillar activity occurs within this tent, which becomes filled with leaf fragments, cast skins, and frass. Fully grown larvae then wander from the webs and pupate in protected areas such as the leaf litter where they will remain for the winter. Adult fall webworm moths emerge the following spring/early summer to start the cycle over again. 50+ species of parasites and 36+ species of predators are known to attack fall webworm in North America. Fall webworms typically do not cause extensive damage to their hosts. Nests may be an aesthetic issue for some. If in reach, small fall webworm webs may be pruned out of trees and shrubs and destroyed. Do not set fire to H. cunea webs when they are still attached to the host plant.

• Hickory Tussock Moth: Lophocampa caryae is native to southern Canada and the northeastern United States. There is one generation per year. Overwintering occurs as a pupa inside a fuzzy, oval shaped cocoon. Adult moths emerge approximately in May and their presence can continue into July. Females will lay clusters of 100+ eggs together on the underside of leaves. Females of this species can fly, however they have been called weak fliers due to their large size. When first hatched from their eggs, the young caterpillars will feed gregariously in a group, eventually dispersing and heading out on their own to forage. Caterpillar maturity can take up to three months and color changes occur during this time. These caterpillars are essentially white with some black markings and a black head capsule. They are very hairy, and should not be handled with bare hands as many can experience skin irritations or rashes (dermitis) as a result of interacting with hickory tussock moth hairs. By late September, the caterpillars will create their oval, fuzzy cocoons hidden in the leaf litter where they will again overwinter. Hosts whose leaves are fed upon by these caterpillars include but are not limited to hickory, walnut, butternut, linden, apple, basswood, birch, elm, black locust, and aspen. Maple and oak have also been reportedly fed upon by this insect. Several wasp species are parasitoids of hickory tussock moth caterpillars.

• Lace Bugs: Stephanitis spp. lacebugs such as S. pyriodes can cause severe injury to azalea foliage. S. rhododendri can be common on rhododendron and mountain laurel. S. takeyai has been found developing on Japanese andromeda, leucothoe, styrax, and willow. Stephanitis spp.lace bugs should be monitored through September. Fall or early spring soil treatment with imidacloprid has been effective, but be aware of the implications this may have on pollinators attracted to these flowering plants when making management decisions. Certain azalea and andromeda cultivars may be less preferred by lace bugs.

• Tuliptree Scale: Toumeyella liriodendri is a species of soft scale insect (Family: Coccidae) that is native to the United States and found in much of the eastern US, but also has been recorded in California. It appears to be present wherever host trees are found. It is another one of the larger scale insects found in the United States, a close second in size to the magnolia scale. Adult female tuliptree scales can measure up to ¼ to just under ½ inch in length. Host plants include Liriodendron tulipifera (tuliptree or yellow poplar), Magnolia stellata (star magnolia), and M. soulangeana (Chinese magnolia). This insect has also been recorded on M. grandiflora (southern magnolia), Tilia spp. (linden), and to a lesser extent, on other ornamental trees and shrubs. When this insect is present on magnolias, such as those mentioned above, it is often confused for the magnolia scale (Neolecanium cornuparvum). The two may be similar in size and have similar life cycles. The mature female tuliptree scale is hemispherical in shape. Color of the mature female varies in this species as well, a grayish-green to pink-orange insect mottled with black. Adult males emerge sometime in June and mate with the females. Eggs develop within the body of the female tuliptree scale, leading to the “live birth” of immatures (crawlers) in late August and September. In the Northeast, one generation of tuliptree scales occurs per year. (However, in the southern-most portions of its range, this insect has been found in all stages of development during the winter, suggesting multiple generations per year.) A single female tuliptree scale may produce 3,000+ crawlers in one season. These crawlers are tiny (approximately the size of the head of a pin) and settle on host plant twigs in September. Past studies have shown that in addition to moving on their own with fully functional legs, the crawlers can be blown to new hosts on the wind, up to 100 feet away. (Being wind-blown to a new host, however, is a haphazard method of travel through which some less than 20% of these crawlers successfully make contact with a host plant, and fewer still attach to a suitable site on the plant.) The immature, crawler stage molts once prior to overwintering. The natural enemies of the tuliptree scale include certain lady beetle species (Hyperaspis signata, Adalia (formerly Hyperaspis) bipunctata, and Chilocorus stigma) which feed on nymphal scales, a number of parasitic wasps, and even an insect-feeding moth caterpillar (Laetilia coccidivora). This particular moth species, also referred to as a type of snout moth, will consume the tuliptree scale underneath the protection of a silken web it spins over them. (The specific epithet coccidivora can be translated as “ones that eat soft scales” or Coccidae.) Unfortunately, in a landscape setting, it often seems that although these natural enemies may be common within the scale populations, they are seldom able to reduce the scale insect numbers below damaging levels. That being said, our management options should seek to preserve these natural enemies.

Management options for the tuliptree scale (Touymeyella liriodendri) include mechanical management by removing scales by hand or pruning and destroying infested plant material when practical/possible. High-pressure water sprays can at times dislodge scale insects from smaller host plants, yet care must be taken to avoid plant damage. Although this is a soft scale, foliar applications of insecticides should still target the crawler or immature stages of this insect, as the tuliptree scale is covered with a protective waxy layer for most of its life cycle. Many active ingredients are also available for use against the tuliptree scale, but reduced risk products may include horticultural oil, insecticidal soap, and neem oil. Dormant oils may be applied between 12-121 Growing Degree Days, Base 50°F, for this pest. Foliar insecticides may be applied between 2032-2629 Growing Degree Days, Base 50° F, or roughly in late August through mid-September.

• Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. Adult beetles are expected to be active roughly through October, or when the first frost hits. Adult beetles will create their own feeding damage, but will also mate and females will lay eggs in the stems of the viburnums, typically beginning in late-June to mid-July until October. This beetle feeds exclusively on many different species of viburnum including but 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/.
• Chilli Thrips: The non-native, exotic chilli thrips (Scirtothrips dorsalis) has been confirmed from two samples of damaged Hydrangea spp. foliage from two residential landscapes located in Barnstable County, MA submitted to the UMass Plant Diagnostics Laboratory. At this time, this pest has not been confirmed in nurseries or greenhouses in Massachusetts or on any other host plants. Due to the limited number of samples, the significance of chilli thrips in Massachusetts is not yet known. This species of thrips is a significant global pest of economically important ornamental, vegetable, and fruit crops in southern and eastern Asia, Oceania, and parts of Africa. It was first determined to be established in the United States in 2005 in Florida, although previous interceptions of this pest were detected. It is reportedly a pest of over 100 host plants belonging to over 40 plant families, including, but not limited to, pepper, strawberry, blueberry, cotton, rose, peanut, Japanese privet, Rhododendron spp., Viburnum spp., eggplant, grapes, melon, tobacco, and tomato. For more information, please visit this Chilli Thrips Fact Sheet: https://ag.umass.edu/landscape/fact-sheets/chilli-thrips

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.

Pollinator Protection Resource Online: The Massachusetts Department of Agricultural Resources has developed a Massachusetts Pollinator Protection Plan. It is a set of voluntary guidelines that discuss best management practices for stakeholders seeking to promote the health of the European honeybee and other pollinators. This document includes information for beekeepers, pesticide applicators, land managers and farmers, nurseries and landscapers, and homeowners and gardeners. Please locate the MA Pollinator Protection Plan for more information here: http://www.mass.gov/eea/docs/agr/farmproducts/apiary/pollinator-plan.pdf.

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

Other Relevant News/Pest Alerts

New England GROWS takes place on November 29 - December 1, 2017, at the Boston Convention and Exhibition Center.  For the latest information, download the GROWS mobile app; follow New England GROWS on Facebook and Twitter; visit NewEnglandGrows.org or call (508) 653-3009.

• GROWS Attendee Brochure: http://tinyurl.com/GROWSGuide17
• GROWS Marketing Guide: http://tinyurl.com/GROWSBrand17

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