Landscape Message: August 24, 2018

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 August 22, 2018. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2018 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	2018 Total	Sun	Shade
CAPE	341	1973	73	70	1.23	1:00 AM 8/22
SOUTHEAST	351.5	2105	73.7	69.5	3.60	5:00 PM 8/22
NORTH SHORE	313.5	2071.5	70	66	3.19	8:30 AM 8/22
EAST	330.5	2270.5	74	68	2.96	4:45 PM 8/22
METRO	317	2078	70	68	5.48	5:45 AM 8/22
CENTRAL	n/a	2102.5	65	60	4.34	7:00 AM 8/22
PIONEER VALLEY	313.5	2201	76	69	4.99	9:00 AM 8/22
BERKSHIRES	295	1929	71	66	5.26	8:30 AM 8/22
AVERAGE	302	2031	72	67	3.88
n/a = information not available

Drought conditions update: Viewing the map via the link below, dated August 21, shows Massachusetts is experiencing level D0 - 'Abnormally Dry' - in all areas of Cape Cod, Martha's Vineyard and Nantucket. The vast majority of Bristol and Plymouth Counties are also labeled D0.  The rest of the state is free of any category of drought.
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.
Polygonum cuspidatum (Japanese Knotweed)	Begin	Full	Begin	Begin	Begin	*	Begin	*
Styphnolobium japonicum (L.) Schott (Japanese Pagoda tree)	*	Full	Full/End	End	Full	Full	Full	Full
Clethra alnifolia (Summersweet Clethra)	Full	Full/End	Full	Full/End	Full/End	Full	Full/End	Full/End
Buddleia davidii (Butterfly Bush)	Full	Full	Full	Full/End	Full/End	*	Full	Full/End
Hibiscus syriacus (Rose-of-Sharon)	Full	Full	Full/End	Full/End	Full/End	End	Full/End	Full/End
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature over the last two weeks was 74°F with a high of 89°F on August 16 and a low of 65°F on August 20 & 21. Overall, the period had daytime highs in the 80s and nighttime lows in the 70s or upper 60s. A break in the high temperatures occurred on August 19, starting several days with highs around 70°F. The majority of the period featured conditions of high humidity. In numerous precipitation events, 1.23 inches of rain fell during this period. Between the high humidity and frequent precipitation events, conditions were conducive to the build up of late season foliar diseases. Top soil and sub soil moisture conditions are adequate.

Pests/Problems: Insects or insect damage observed over the last week include: Asiatic beetle (typically seen only at night), sunflower moth (Homoeosoma electellum) on purple coneflower, tobacco budworm on petunia, chinch bug damage to turf, white pine weevil (Pissodes strobe) damage on white pine, ambrosia beetles and damage on holly, bark beetle damage to eastern red cedar, Lecanium scale on oak, turpentine beetle (Dendroctonus terebrans) on pitch pine, two spotted spider mite on annuals and herbaceous perennials, Andromeda lacebug (Stephanitis takeyai) on Japanese Andromeda, azalea lacebug (Stephanitis pyrioides) on azalea, sycamore lacebug (Corythucha ciliate) on sycamore, and daylily leafminer (Ophiomyia kwansonis) damage on daylily. Diseases visible over the last week include leaf spot on Hydrangea, powdery mildew on the usual (phlox, Monarda, lilac, peony, dogwood), leaf spots (Septoria) on red twig dogwood, daylily leaf streak on daylily, Kabatina blight (possible Phomopsis as well) on eastern red cedar, leaf spot on birch, tar spot on Norway maple, black spot on rose, and cedar apple rust on crabapple.

Southeast Region (Acushnet)

General Conditions: The rain has been a refreshing addition to the area for the past two weeks, with a total of 3.60”. The recent drop in temperature, with some evenings in the 60’s, is quite a relief from the very long stretch of hot and humid weather we were having. Many beautiful, colorful things are going on in the landscape. Apples, pears and crabapples are looking quite lovely. We are beginning to see the fruit of roses, especially the large Rosa rugosa hips. Drupes are obvious on Viburnum spp. and dogwood (Cornus kousa) has green drupes. Golden raintree (Koelreuteria paniculata) has a stunning display of lantern-shaped seed pods all aglow. Japanese snowbell (Styrax japonicas) is quite pretty with little porcelain-colored drupes dangling in the breeze. Rose of Sharon (Hibiscus syriacus) are blooming gorgeously along with the spectacular Hydrangea paniculata. Mimosa trees (Albizia julibrissin) have been a sight to see with pink powdery blooms. Japanese pagoda trees (Styphnolobium japonicum) are very lovely. Crape myrtle (Lagerstroemia indica) is now starting to flower while some Magnolias are producing a second bloom. Chase tree (Vitex agnus-castus) is quite beautiful with its violet flowers and butterfly bushes (Buddleia davidii) are still attracting butterflies. Many perennials are putting on a show to be admired now, such as: black eyed Susans (Rudbeckia spp.), coneflowers (Echinacea spp.), tickseed (Coreopsis spp.), butterfly weed (Asclepias tuberose) and perennial Hibiscus (Hibiscus spp.). Stonecrop (Sedum spp.) are beginning to show color as well. Trumpet vine (Campsis radican) is still quite brilliant. Bittersweet, goldenrod, pokeweed, nightshade, black swallow wart, common evening primrose (Oenothera biennis), swamp milkweed and Joe Pye weed can still be seen in wetlands and overgrowth areas.

Pests/Problems: Purslane, clover, crabgrass and spotted spurge are still visible. Powdery mildew, sooty mold, rust, tar spot and marginal leaf scorch have all been common problems. Beetles, aphids, spider mites, grasshoppers, slugs, skunks, woodchucks, chipmunks and rabbits are all around. Poison Ivy and mosquitoes are abundant in many areas. Please be aware of wasps and their nests - they can be pretty mean and aggressive.

North Shore Region (Beverly)

General Conditions: This reporting period started with hot and humid conditions, but in the last days of the two week period, the temperatures have moderated into more seasonable, comfortable temperatures. During the first part of the period, day temperatures were in the 80s with high humidity, but in the last few days, the day temperatures have been in the low 70s. There has been several days of rain showers with approximately 3.19 inches of rain recorded at Long Hill. Soils are saturated. Woody plants seen in bloom include: panicle Hydrangea (Hydrangea paniculata), butterfly bush (Buddleia davidii), rose-of-Sharon (Hibiscus syriacus), summer sweet Clethra (Clethra alnifolia) and trumpet vine (Campsis radicans). Herbaceous plants seen in bloom include: Culver’s root (Veronicastrum virginicum), false Anemone (Anemonopsis macrophylla), cardinal flower (Lobelia cardinalis), blue Lobelia (Lobelia siphilitica), garden phlox (Phlox paniculata), Hostas (Hosta spp.), Sedums (Sedum spp.), Clematis vines (Clematis paniculata), Russian sage (Perovskia atriplicifolia), feverfew (Tanacetum parthenium), Rudbeckia (Rudbeckia hirta), coneflower (Echinacea purpurea), water lily (Nymphaea odorata) and an assortment of summer annual plants.

Pests/Problems: Cedar apple rust (Gymnosporangium juniperi-virginianae) and other fungal diseases such as apple scab (Venturia inaequalis) are being found on crabapples and are causing early leaf drop on some crabapple trees. Powdery mildew was observed on lilac and Phlox, tar spot on maples, leaf blotch on horse chestnut (Aesculus carnea) and black spot on roses. Weeds continue to thrive in landscapes. Some of the weeds observed in bloom include: white clover (Trifolium repens), yellow woodsorrel (Oxalis stricta), purslane (Portulaca oleracea), prostrate spurge (Euphorbia maculata), bittersweet nightshade (Solanum dulcamara), Japanese knotweed (Polygonum cuspidatum), pigweed (Amaranthus retroflexus), ragweed (Ambrosia artemisiifolia) and goldenrod (Solidago spp). Mushrooms were observed growing on lawn areas. Ticks and mosquitoes continue to be very active. Always protect yourself with repellent when working or walking outdoors in the woods.

East Region (Boston)

General Conditions: Temperatures have been more pleasant over the last two weeks as highs averaged 80°F, ranging from 70°F to 90°F, and lows averaged 67°F, ranging from 62°F to 71°F. Precipitation has been abundant; we received rain on nine days for a total of 2.96 inches. Despite this abundance of rain, we received no day-long soakers; when rain fell, it lasted at most a few hours. Downpours were common, with the heaviest downpour occurring on August 8, when 0.71 inches fell over a 45-minute period. Plants in bloom include: Albizia julibrissin (silktree), Asclepias incarnata (swamp milkweed), A. syriaca (common milkweed), A. tuberosa (butterflyweed), Buddleia alternifolia 'Argentea' (fountain butterfly bush), Clerodendrum thomsoniae (bleeding heart vine), C. trichotomum (harlequin glorybower), Doellingeria umbellata (parasol whitetop), Eutrochium purpureum (purple Joe-Pye weed), Helianthus tuberosus (Jerusalem artichoke), Heuchera spp. (coral bells), Hibiscus moscheutos (swamp rosemallow), Monarda didyma (scarlet beebalm), Pycnanthemum virginianum (mountain mint), Rudbeckia fulgida 'Goldsturm' (Goldsturm coneflower), Silphium perfoliatum (cup plant), Solidago spp. (goldenrod), Tanacetum parthenium (feverfew), and T. vulgare (tansy).

Pests/Problems: Soils have been moist; supplemental irrigation has been unnecessary even for recent plantings. Leaf blotch is apparent on Aesculus sp. (horsechestnut) and powdery mildews are abundant throughout the landscape on Cornus spp. (dogwood), Phlox spp. (Phlox), and Syringa spp. (lilac). Wasps and ground nests are becoming more visible. As wasps, bees, and hornets are preparing for winter, the threat of stings is increased at this time of year.

Metro West (Acton)

General Conditions: Summer is coming to an end. Day length is shorter - currently at 13:39, with sunrise at 7:57 a.m. and sunset at 7:36 p.m. - and is getting shorter every day. Plants are heavy with fruit, seed, berries, and nuts and temperatures are cooling off. The historical monthly average rainfall for August is 3.72”. During this past two-week reporting period, 5.48” of rain was recorded with 3.27” measured on the 8^th, 0.89” on the 11^th, 0.49” on the 18^th, followed by a smattering more which brought the total for the month to 6.42”. Needless to write, soils are well saturated and ready for planting. In some stage of bloom at this time are the following woody plants: Albizia julibrissin (silk tree), Buddleia spp. (butterfly bush), Campsis radicans (trumpet vine), Clethra alnifolia (summersweet), Hibiscus syriacus (rose-of-Sharon), Hydrangea paniculata (panicle Hydrangea) and its many cultivars including 'Tardiva', Potentilla fruiticosa (Potentilla), Rosa 'Knockout' (The Knockout family of roses) and Styphnolobium japonicum (Japanese pagoda tree). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Achillea millefoliumn (yarrow), Asclepias syriaca (common milkweed) and A. tuberosa (butterfly weed), Astilbe spp. (false Spirea), Boltonia asteroides (Bolton’s aster), Cichorium intybus (chicory), Coreopsis spp. (tickseed), C. verticillata (threadleaf Coreopsis), Daucus carota (Queen Anne's lace), Echinacea purpurea (coneflower) and its many cultivars, Eupatorium purpureum (Joe Pye weed), Geranium sanguineum (cranesbill Geranium), Hemerocallis spp. (daylily), Hosta spp. (plantain lily), Kirengeshoma palmata (yellow wax bells), Lavendula angustifolia (lavender), Leucanthemum spp. (shasta daisy), Liatris spicata (spike gayfeather), Lythrum salicaria (loosestrife), Patrinia gibbosa (Patrinia), Perovskia atriplicifolia (Russian sage), Phlox carolina (Carolina Phlox), P. paniculata (garden Phlox), Platycodon grandiflorus (balloonflower), Rudbeckia fulgida var. sullivantii  'Goldsturm' (black-eyed Susan), Senna marilandica (wild Senna), and Solidago spp. (goldenrod).

Pests/Problems: Observed in the landscape these past two weeks were leaf blotch on Aesculus sp. (horsechestnut), cedar apple rust on Amelanchier spp. (serviceberry) and Crataegus spp. (hawthorn), the leaf chewing blister beetle feeding on Clematis recta ‘Purpurea’, and powdery mildew on Cornus florida (dogwood), Hamamelis spp. (witch hazel), Monarda spp. (bee-balm), Phlox spp. and Syringa vulgaris (lilac).

Central Region (Boylston)

General Conditions: Warmth and humidity prevaled over the last two weeks, with a slight moderation toward the end of the reporting period. Several heavy precipitation events during this reporting period brought a total of over 4” of rain. Trees, shrubs and vines in bloom include: Calluna vulgaris spp. and cvs. (heather), Clerodendron trichotomum (harlequin glorybower), Clethra acuminata (mountain pepperbush), C. alnifolia (summersweet), C. barbinervis (Japanese Clethra), Hibiscus syriacus cvs. (rose of Sharon, almost done), Styphnolobium japonicum (Japanese pagoda tree), Hydrangea aspera (rough-leaved Hydrangea), H. macrophylla ‘Bailmer’ (endless summer Hydrangea), H. paniculata (panicle Hydrangea), H. quercifolia (oak-leaf Hydrangea), H. serrata ‘Bluebird’ (mountain Hydrangea), Clematis cvs (Clematis vines), in particular C. heracleifolia var. davidiana (tube Clematis) and C. ‘Rooguchi’. The following perennials and bulbs are in bloom: Ageratina altissima ‘Chocolate’ (white snakeroot), Anemone japonica ‘Pamina’ and ‘Robustissima’ (Japanese Anemones), Anemonopsis macrophylla (false Anemone), Angelica gigas (purple parsnip), Echinacea spp. and cvs. (coneflower), Echinops bannaticus (blue globe-thistle, winding down), Eryngium ‘Blue Hobbit’ (dwarf sea holly, winding down), Eupatorium purpureum (Joe Pye weed), Galtonia candicans (summer Hyacinth), Geranium ‘Gerwat’ (Geranium Rozanne), Indigofera amblyantha (Chinese indigo), Kniphofia ‘Jade Green’ (red hot poker plant), Leucanthemum x superbum ‘Becky’ (shasta daisy, winding down), Liatris spicata (gayfeather, winding down), Phlox paniculata (garden Phlox), Rudbeckia fulgida var. sullivantii ‘Goldsturm’ (brown-eyed Susan), R. subtomentosa ‘Henry Eilers’ (sweet coneflower), Senna marilandica (wild senna), Solidago spp. and cvs. (goldenrod), Stenanthium gramineum (eastern featherbells), Vernonia noveboracensis (ironweed), and Veronicastrum virginicum (Culver’s root).

Pests/Problems:  Magnolia scale on Magnolia spp. and cvs. - adult females are very visible at this time. Dogwood sawfly has been noted on grey dogwood, Cornus sanguinea ‘Midwinter Fire’ and Cornus sericea ‘Bud’s Yellow'.  Japanese beetles are still active. Budworms are on flowering perennials and annuals. Snails and slugs are becoming more noticeable in the landscape with recent consistent moisture. Blister beetles are on Clematis, Anemone japonica, and Anemone pulsatilla. Powdery mildew was noted on Syringa spp. (lilacs), Phlox paniculata (garden Phlox), and Monarda spp. and cvs. (bee-balm). Cedar-apple rust is on Malus (crabapple and apples)

Pioneer Valley Region (Amherst)

General Conditions: The Pioneer Valley has received a staggering amount of rainfall over the past six weeks. Since July 15, rainfall totals have ranged from 9.3″ to 16.3″ at various weather stations in the valley. Franklin County has received the most, with total accumulation >14″ at several weather stations while portions of Hampshire County have “only” received between 9–10″. Totals in Hampden County have hovered between 12–14″. The constant rain, coupled with the high heat and humidity, has created almost tropical-like conditions at times. The late season rain has been a boon to weeds in the landscape and weeding ornamental beds is now a full time job in itself. Crabgrass growing in full sun settings is thick and lush, clogging mowers even on the tallest settings. With all of this late summer rainfall, we can be deceived into thinking that recently transplanted trees and shrubs do not require supplemental irrigation. While this may be the case in some settings, in others it may not. It’s been a very hot and humid summer, meaning water loss through transpiration has been high. Soils that are shielded from receiving rainwater due to a dense canopy (e.g. eastern hemlock) should be carefully checked to determine if supplemental water is needed at this time. Clearly, overwatering should be avoided given how wet it’s been but don’t assume new transplants are getting all that they need. Mushrooms and conks continue to appear in large numbers in landscape and forest settings. It’s a great year for mushroom foraging and finding wood-rotting pathogens on or near large trees. Since the storm system that swept through on 8/18, temperatures have cooled dramatically and nighttime lows have dropped into the 50s. The long-term forecast calls for a mix of cool and warm weather and a lack of rain, something we haven’t experienced since the early part of July.

Pests/Problems: Apple scab-induced leaf shedding continues on apple and crabapple in the landscape. Many trees have yellowing and shedding leaves, especially on interior canopy branches. Some trees are nearly devoid of any defoliation, similar to 2017. Entomosporium leaf spot is becoming more prominent on hawthorn. While common, the pathogen seems to cause little harm. Leaf spots and blotches are widespread on oaks at this time and may be due to either oak anthracnose, Tubakia leaf blotch or both diseases. Damage from the oak leaf skeletonizer, a late season pest in the region, is also widespread at this time. Overall, the skeletonizer damage is minor, especially when compared to spider mite injury on landscape oaks. Many young and mature oaks on the UMass campus are suffering from severe spider mite infestations this year. The feeding damage that results in the characteristic “flecking” symptoms has given foliage a pale green to bronze appearance and the white-colored cast skins of spider mites are readily observable on the upper surface of the leaves. Lacebug damage on serviceberry and sycamore is also abundant this year.

Berkshire Region (Great Barrington)

General Conditions: Wet weather continues to be the main story over the past two weeks as over 5 inches of rain fell in many parts of Berkshire County. Most notable was a fierce thunderstorm which dropped 3.26 inches of rain on Friday night, August 17, as measured at our new monitoring site in West Stockbridge. The torrential rainfall resulted in some flash flooding and considerable erosion, which carried sand, gravel, and even some large rocks onto roadways. Much debris, often tree limbs, was washed into streams and clogged culverts. This enhanced some local flooding of roadways and also deposited much debris on roads. The storm was accompanied by frequent lightning. Needless to say, the frequency and volume of rain has left soils saturated. Rainfall on other days had an odd pattern of brief rain followed by a brief breakthrough of sun or at least a cessation of rain, then another brief bout of rain, sun, rain, sun. That pattern was typical today, August 22. Though the rain had many negative effects as mentioned below, much of the landscape appears verdant and colorful as mid-summer perennials are at their peak. Hydrangeas, particularly H. paniculata cultivars have been quite showy. Turfgrass growth seems to have benefited from the rain and is growing rapidly.

Pests/Problems: When this amount of rain falls and with such frequency, plant disease problems abound. Among the diseases prominent in the landscape are: powdery mildew on many perennials, annuals, vegetable crops and susceptible shrubs, botrytis on peony, daylily streak on many daylily cultivars, tar spot on Norway maples, and an assortment of other leaf spots and blights. Cedar apple rust on crabapples has had a banner year and many susceptible crabapple cultivars are rapidly shedding their leaves. Leaf and stem decay has demolished many annuals and perennials. The rain may have had the effect of diminishing some insect populations. Insects observed during scouting this week include: Japanese beetles (though numbers are greatly reduced), Viburnum leaf beetle adults, Magnolia scale crawlers, and Euonymus scale crawlers (2^nd generation). Tussock moth caterpillars are common on hickory. The T-storm of August 17, as mentioned above, was accompanied by frequent lightning and there are reports of trees having been struck. The frequent rain has also caused considerable leaching of nitrogen from soils. The effect of depleted nitrogen can be seen in the yellowing or at least the fading of green in plant foliage.

Regional Scouting Credits

• CAPE COD REGION - Russell Norton, Horticulture and Agriculture Educator with Cape Cod Cooperative Extension, reporting from Barnstable.
• SOUTHEAST REGION - Jacqueline Hoyle, MCH, reporting from Acushnet.
• 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  - Dawn Davies, Interim Horticulture Manager, 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:

Diplodia shoot and needle blight, caused by Diplodia sapinea, on Japanese black pine (Pinus thunbergii). The tree resides in a residential setting on a barrier island in southern New Jersey and is believed to have been planted sometime in the 1920s. Over the past several years, needle browning and branch dieback has developed and worsened. The submitted sample was negative for the pinewood nematode, which can be very aggressive on this host. Diplodia was abundant on submitted needles and shoots and appears to be the sole cause of decline.

Verticillium wilt of bottlebrush buckeye (Aesculus parviflora). Tree is six-years-old and has been present at the site for nearly as long. In June of this year, leaves began yellowing and prematurely shedding from the canopy. The tree was planted in a shaded setting near several mature deciduous hardwoods that all serve as hosts of Verticillium and does not receive supplemental water. There was a lack of vascular staining on the submitted branch segments but after incubating the tissue, characteristic mycelia and microsclerotia (black-colored, seed-like structures that allow the fungus to persist in plant tissues and soil) were produced.

Armillaria root and trunk rot of Carolina allspice (Calycanthus raulstonii 'Hartlage Wine'). Shrub is 12-years-old and is growing in an arboretum in loamy sand with full sun. In mid-August, leaf wilting developed in part of the canopy and further inspection found swollen ridges on the bark. The affected canopy quickly declined and died. Removal of the bark revealed white mycelial fans produced by Armillaria. In many cases, attack from Armillaria leads to water starvation as the fungus kills phloem and sapwood tissue in the roots and root collar. It doesn’t often progress up into the canopy as the entire lower portion of the trunk is girdled. But in this case, the fungus advanced upward into the canopy from the roots while the plant is still alive. Infection from Armillaria is ultimately lethal, however it can take many years to decades until the fungus, along with other opportunistic pests and pathogens, finally overcomes the host.

Severe infestation of privet thrips (Dendrothrips ornatus) on privet (Ligustrum sp.). Twenty 5-6' privets were installed as a hedgerow in 2016 and receive full sun and supplemental irrigation. The plants were sprayed with bifenthrin by a lawn care company in middle and late July as part of a “general insect treatment program” and was not targeted to any particular pest. Soon after the treatments, leaves began to yellow and prematurely shed from the canopy. Submitted foliage exhibited severe flecking symptoms and numerous live thrips were observed. Previous research has shown that bifenthrin does not provide good control of privet thrips but does work well in eliminating many natural predators that may be present. Neighboring privet hedges that were untreated are robust and healthy. No other pests or pathogens were detected from the submitted sample.

Lower canopy dieback of Robusta green juniper (Juniperus chinensis 'Robusta Green') caused by Phomopsis juniperovora and Pestalotiopsis. Six trees in a hedgerow that are approximately 10-years-old. The lower 2/3 of the canopy appear very thin with short branches and sparse foliage. The upper 1/3 of the canopy is full and robust. The trees reside in full sun and may receive some supplemental water from lawn irrigation. Phomopsis can be very destructive on junipers causing needle and stem blight. If lawn sprinklers are wetting the lower canopy of the trees, then this practice is facilitating disease development and spread by providing free moisture for spore germination and dispersal.

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

Insects

Notable Caterpillars:

• Definite Tussock Moth: (Orgyia definita)  The definite tussock moth caterpillar belongs in the tussock moth subfamily Lymantriinae. Formerly the family Lymantriidae, this group of species gets its name from the dense tufts of hair or tussocks that adorn the caterpillars. Approximately 20 species occur in eastern North America (Wagner, 2005). The caterpillars of O. definita are bright yellow with four cream-yellow mid-dorsal tufts and a colorless or blackish stripe down the middle of the back of the caterpillar (mid-dorsal). This species has been noted from fields to forests from southern Canada to Florida and Louisiana. There can be two generations in much of its range, and mature caterpillars may be found from April-September. Host plants include basswood, birch, blueberry, elm, hackberry, maple, oak, willow, and other woody plants. Adult female moths are wingless and lay a single cluster of eggs over the outer surface of their own cocoon. First instar caterpillars can disperse by ballooning. Eggs are the overwintering stage. While Wagner (2005) lists this insect as a very common species, I have been more likely to run into the caterpillars of the hickory tussock moth (Lophocampa caryae) than Orgyia spp. in recent months. Contact with the caterpillars or cocoons of many Orgyia spp. can lead to unpleasant skin irritation or dermatitis. Again, although it is possible to see these caterpillars in the landscape, their numbers are generally not so large as to cause concern due to the potential for allergic reactions to their hairs. (Exposure risk may be low.) So no need to panic. It is wise, however, to recognize the caterpillars of the tussock moths and “look, but do not touch”.
• Drexel’s Datana: (Datana drexelii ) The caterpillars of Drexel’s datana may be found from Nova Scotia to Kentucky and South Carolina. In the northern portion of this insect’s range, one generation occurs per year. Blueberry, other heaths, and witch hazel are reported as hosts. This species is one of four in the genus Datana which have similar looking caterpillars. D. ministra or the yellow-necked caterpillar may be found on similar hosts, but tends to be primarily black in color with yellow stripes down the sides. Angus’s Datana (D. angusii) has reddish prolegs, a black thoracic shield, and may be hairier. For that species, butternut, hickory, and walnut are listed as preferred. The spotted Datana (D. perspicua) may have broader yellow stripes and the base of each proleg is somewhat reddened, favoring sumac, smoketree, and possibly oak. D. drexelii pictured here may be distinguished from the others by an “orange rump patch” which is formed by the convergence of some of its stripes (Wagner, 2005). Datana spp. caterpillars have been reported as in decline, perhaps due to the impact of Compsilura concinnata, a tachinid fly parasitoid released very early on (1906) in the fight against gypsy moth (Lymantria dispar). Unfortunately, that tachinid fly species is a generalist and not specific to the gypsy moth. Therefore, if you find a cluster of these caterpillars munching away and they can be tolerated in their given location, leave them be. They make for enjoyable viewing if you appreciate the various yoga-like poses they take.

A New Fact Sheet:

• Need an overview of the chemically active ingredients available to manage insect pests of ornamental trees and shrubs? The following fact sheet provides this list, in addition to a summary of some of the pests they target as well as risks to pollinators and other non-target organisms: https://ag.umass.edu/landscape/fact-sheets/tree-shrub-insecticide-active-ingredients-risks-to-pollinators-other-non

This reference is meant to assist landscape practitioners, industry professionals, land managers, and property owners in their decisions about chemical management. It is not meant to replace product labels. If this fact sheet contradicts the product label, follow the product label. The list and the information within may not be complete. New chemistries become available frequently, making lists such as these difficult to keep up-to-date.

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 believe you have captured or taken a photo of an adult insect, 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 .

• Asiatic Garden Beetle: Maladera castanea adults are active and are typically most abundant in July and August. These rusty-red colored beetles are bullet-shaped and active at night. They are often attracted to porch lights. They feed on a number of ornamental plants, defoliating leaves by giving the edges a ragged appearance and also feeding on blossoms. Butterfly bush, rose, dahlia, aster, and chrysanthemum can be favored hosts.

• Deer Tick/Blacklegged Tick: Ixodes scapularis adult females, following a blood meal, can lay a single egg mass (up to 1500 – 2000 eggs) in mid-late May, and then the female deer tick perishes. Larvae emerge from the eggs later in the summer. Larvae are tiny and six-legged. Prior to feeding, they are not known to be able to transmit disease. After feeding, the larvae drop from their host and molt, re-emerging the following spring as nymphs. Nymphs (from last year’s overwintering cohort) are active from May-August. Nymphs are eight-legged and about the size of the head of a pin. These tiny nymphs typically attach to small mammal hosts; however, they will readily feed on people and pets. Nymphs are capable of carrying Lyme disease, human Babesiosis, human Anaplasmosis, and deer tick virus. For images of all deer tick life stages, along with an outline of the diseases they carry, visit: http://www.tickencounter.org/tick_identification/deer_tick .

Anyone working in the yard and garden should be aware that there is the potential to encounter deer ticks. 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 red “Test A Tick” 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.

You can also follow TickReport on Twitter @TickReport for timely updates from the Laboratory of Medical Zoology, including the latest tick and tick-borne disease related research.

• Emerald Ash Borer: (Agrilus planipennis, EAB) New community detections of this insect (in Massachusetts) were made earlier in August. Reports from Dover (Norfolk County), Holliston, and Lexington, MA (Middlesex County) were all confirmed by the MA Department of Conservation and Recreation. Detections of EAB were made in Franklin (Norfolk County) and Harvard, MA (Worcester County) by the MA Department of Agricultural Resources and their surveys of Cerceris fumipennis aggregations. C. fumipennis is a native, non-stinging, ground-nesting wasp that hunts jewel beetles, including EAB, and can be used to monitor for this invasive pest through a technique known as biosurveillance. For more information about Cerceris fumipennis, view “News for Gardeners” here:

https://ag.umass.edu/home-lawn-garden/newsletters/garden-clippings/garden-clippings-2018-vol-375 .

This wood-boring beetle readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus) and most recently, has been reported in cultivated olive (Olea europaea). Signs of an EAB infested tree may include D-shaped exit holes in the bark (from adult emergence), “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

• Fall Home-Invading Insects: Various insects, such as ladybugs, boxelder bugs, seedbugs, and stink bugs will begin to seek overwintering shelters in warm places, such as homes, throughout the next couple of months. While such invaders do not cause any measurable structural damage, they can become a nuisance especially when they are present in large numbers. While the invasion has not yet begun, 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 a two-species complex. 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. Fall webworm caterpillars were reported for 2018 previously in the Pioneer Valley Region report and expanding webs were seen the week of 7/4/18 in Chesterfield, MA. 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.

• Gypsy Moth: Lymantia dispar adult activity is at an end for the 2018 season. The Massachusetts Department of Conservation and Recreation (DCR) has released preliminary numbers for the total acres defoliated by gypsy moth caterpillars in 2018. MA DCR officials estimate that approximately 161,000 acres were defoliated by gypsy moth in 2018. This pales in comparison to the over 923,000 acres of defoliation due to gypsy moth estimated in 2017. (We can thank Entomophaga maimaiga for the population decrease between last year and the beginning of this year.) The acreage number for 2018 is a rough estimate at this time, as state officials are still working on confirming that gypsy moth was responsible for the defoliation they saw from the air, by visiting these locations on the ground to determine that gypsy moth caterpillars were the cause of the defoliation seen. Once final numbers and a map of the 2018 defoliation becomes available, this information will be highlighted in the Landscape Message.

One worrisome note is that Entomophaga maimaiga does not seem to have been as active in the gypsy moth population in 2018 as it was in 2017. This allowed many healthy adult moths to mate and females to lay egg masses that will overwinter and provide us with a population of caterpillars in 2019. More information can be found in the August issue of Hort Notes, which is available here under “Trouble Maker of the Month”: https://ag.umass.edu/landscape/newsletters/hort-notes/hort-notes-2018-vol-298 .

• 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 have skin irritations or rashes (dermatitis) 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.

• Spotted Lanternfly: (Lycorma delicatula, SLF) is not known to occur in Massachusetts. This insect is a member of the Order Hemiptera (true bugs, cicadas, hoppers, aphids, and others) and the Family Fulgoridae, also known as planthoppers. This insect is a non-native species first detected in the United States in Berks County, Pennsylvania and confirmed on September 22, 2014. Until November 2017, this invasive insect was only known to Pennsylvania. It has now been reported from Delaware (November 20, 2017), New York (November 29, 2017), and Virginia (January 10, 2018). The most recent detection of the spotted lanternfly outside of Pennsylvania is an established population in New Jersey as reported by the New Jersey Department of Agriculture on July 17, 2018.

The Delaware Department of Agriculture announced the finding of a single female spotted lanternfly in New Castle County in the Wilmington, Delaware area. At this time, officials in Delaware note that it is unclear if this individual was an accidental hitchhiker, or evidence of an established population in the state. For more information about the find in Delaware, visit: https://news.delaware.gov/2017/11/20/spotted-lanternfly-confirmed-delaware/ . The New York State Department of Agriculture and Markets reported on November 29, 2017 the finding of a single dead individual spotted lanternfly in the state from earlier in the month. A single dead specimen was confirmed at a facility in Delaware County, New York, which is located south-west of Albany. The NYS Dept. of Agriculture and Markets states that this dead individual may have come in on an interstate shipment. For more information about the find in New York, visit: https://www.agriculture.ny.gov/AD/release.asp?ReleaseID=3637 . Virginia Cooperative Extension announced the finding of a spotted lanternfly population in Frederick County, Virginia, on January 10, 2018. It was noted that at the location in Virginia, numerous adult lanternflies and egg masses were discovered, in addition to more at another site approximately 400 yards away. For more information about the find in Virginia, visit: https://ext.vt.edu/agriculture/commercial-horticulture/spotted-lanternfly.html . Most recently, the New Jersey Department of Agriculture reports spotted lanternfly has been confirmed in portions of Warren County, NJ on July 17, 2018. For more information about the find in New Jersey, visit: https://www.nj.gov/agriculture/news/press/2018/approved/press180717.html .

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 .

• 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 was observed in Boston, MA on 5/4/2018. By early to mid-June, Viburnum leaf beetle larvae crawl down the host plant, enter the soil surface, and pupate. This typically occurs when the larvae are just under ½ inch in length. After pupation, by early-July, adult beetles will emerge from the soil and begin feeding on Viburnum foliage again prior to mating and laying eggs. Viburnum leaf beetle adults were very active in Amherst, MA, (observed on 8/6/18) spending their days mating and feeding. Adult females are laying the eggs that will overwinter in pits chewed in host plant stems (toward the terminals) and covered with a cap of chewed bark.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, where they are present, may be treated with a product containing spinosad. 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/ .

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 red Test a Tick button for more information.

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

Plant of the Week

The bright purple blossoms of this tall, native, perennial are currently covered with pollinators!  https://stockbridge.cns.umass.edu/new-york-ironweed

Bridgit Litchfield reporting for Mandy Bayer

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