Landscape Message: June 2, 2017

June 2, 2017
Issue: 
11

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

The Landscape Message will be updated weekly April through June. The next message will be available on June 9. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

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Scouting Information by Region

Environmental Data

The following data was collected on or about May 31. 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.

Region/Location

GDD

Soil Temp
(°F at 4" depth)

Precipitation
(1-Week Gain)

Time/Date of Readings

1-Week Gain

2017 Total

Sun

Shade

Cape Cod

30.5

264

62

56

0.94

4:00 PM 5/31

Southeast

26

278

63

59

1.50

5:20 PM 5/31

North Shore

31

317

56

52

0.76

9:30 AM 5/31

East

39

369.5

63

59

1.46

5:00 PM 5/31

Metro West

46.5

342.5

55

52

1.33

5:30 AM 5/30

Central

33

367

56

55

2.27

11:35 AM 5:31

Pioneer Valley

66

370

61

56

2.41

10:00 AM 5/31

Berkshires

53

298

57

53

1.26

8:45 AM 5/31

AVERAGE

41

326

59

55

1.49

-

n/a = information not available

Drought Conditions Update: All of Massachusetts (100%) is not under official drought status at this time.  For more information see http://droughtmonitor.unl.edu/Home/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.
Hydrangea anomala petiolaris (Climbing Hydrangea) * * * * * * Begin *
Kalmia latifolia (Mountain-laurel) Begin * Begin * Begin * Begin *
Cotinus coggygria (Common Smokebush) * Full * * Begin Begin Begin Begin
Cornus sericea (Red Osier Dogwood) * * Begin Full Begin Begin/Full Full *
Robinia pseudoacacia (Black Locust) * Full Full Full/End Begin Full Full Begin/Full
Kolkwitzia amabilis (Beautybush) Begin Full Begin/Full Full Begin Full Full Begin/Full
Weigela florida (Old Fashioned Weigela) Begin Full Begin Full Begin Full Full Begin
Deutzia spp. (Deutzia species) Begin Full Full Full Begin Full Full Begin/Full
Enkianthus campanulatus (Redvein Enkianthus) Begin/Full Full Full Full Begin/Full Full Full/End Full
Rhododendron carolinianum (Carolina Rhododendron) Full Full End * Full * Full/End *
Rhododendron catawbiense (Catawba Rhododendron) Full Full End Full/End Full Full Full/End Full
Spiraea x vanhouttei (Vanhoutte Spirea) Full/End Full/End Full * Full/End Full Full Full
Aesculus hippocastanum (Common Horsechestnut) Full/End Full/End Full/End End Full/End Full Full/End Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature from May 24 - May 30 was 55° F with a low of 48° on May 25, 28, and 29 and a high of 65° F on May 28. A total of 0.94 inches of precipitation fell over several events on May 25, 26, & 29, these same dates were also cloudy. Soil moisture remains adequate.

Pests/Problems: Gypsy moth continue to feed on hosts plants. Winter moth can still be found feeding on oaks and likely has begun to drop to the soil to pupate in some locations. Viburnum leaf beetle can be found feeding on the undersides of leaves. Boxwood leafminer midges can be found on boxwood. Rose slug sawfly larvae can be found feeding on rose. Columbine sawfly can be found feeding on columbine. Hydrangea leaftier damage is easily seen on Hydrangea arborescens. Sycamore anthracnose damage is intense in some areas. Brown rot is also causing a lot of twig dieback on Kwanzan and other ornamental cherries. Weeds in bloom include; bulbous buttercup (Ranunculus bulbosus), creeping buttercup (Ranunculus repens), black medic (Medicago lupulina), wild strawberry (Fragaria virginiana), autumn olive (Elaeagnus umbellate), honeysuckle (Lonicera spp.), plantain (Plantago major & lanceolata), white campion (Silene alba), pineapple weed (Matricaria matricariodes), and white clover (Trifolium repens).

Southeast Region (Hanson)

General Conditions: The weather remained cool and damp for most of the last week. In the Hanson area, temperatures most days were in the 50’s. News reported that this May was the coolest since 2005. Hanson received 1.50 inches of rain and soils are moist. Once again, cool temperatures and sufficient rain have help to extend color in the landscape and the following plants are, or remain in bloom: Styrax obassia, Rutgers hybrid dogwoods (Stellar series), Prunus serotina (black cherry), Aesculus x carnea (Red Horsechestnut), Liriodendron tulipifera (Tuliptree), Cornus kousa, Cornus controversa, Cornus alternifolia, Laburnum watereri (Goldenchain Tree), Weigela florida, Indigofera sp., numerous Rhododendrons, early azaleas,Wisteria floribunda (Japanese Wisteria), Robinia hispida, Calycanthus floridus (Carolina allspice), Kerria, Aristolochia durior (Dutchman's pipe), numerous viburnums (including Viburnum opulus, V. plicatum var. tomentosum (Doublefile viburnum), V. sargentii), Beautybush, Abelia mosanensis, Chionanthus virginicus, Cytisus scoparius (Scotch broom), Rhododendron, late lilacs like Syringa x prestoniae ‘James MacFarlane’ and Syringa ‘Miss Kim’, Clematis, Camassia sp., Allium, Baptisia australis and Baptisia hybrids, Tradescantia , Anemone canadensis, Amsonia sp., Thalictrum aquilegifolium, Geranium sp., Buglossoides purpurocaerulea, Doronicum sp., Tiarella cordifolia (Foam Flower), Lamiastrum galeobdolon, Lamium, Dicentra spectabilis (Bleeding heart), Saruma henryi, Cypripedium sp.(Lady’s Slipper), Polygonum bistorta ‘Superbum’, Corydalis lutea, Siberian Iris, bearded iris, Phlox subulata, Phlox divaricata, Phlox stolonifera, Hyacinthoides hispanica, Trillium sp., Galium odoratum (Sweet Woodruff), Convallaria majalis (Lily-of-the-valley), Myosotis sylvatica, Polygonatum sp. (Solomon's Seal), Stylophorum diphyllum (Wood Poppy), Arisaema dracontium, Arisaema ringens, and other Arisaema sp. (Jack-in-the-pulpit), Ajuga, Bearded Iris, Lunaria annua (honesty or money plant), Mertensia virginica (Virginia bluebells), Aquilegia sp. (Columbine) Myosotis sylvatica (Forget-me-not), Vinca minor and Baptisia. Cotinus obovatus (American Smoketree)and Cotinus coggygria (Smokebush) are also in full bloom, with their small, greenish-yellow flowers; the interesting and colorful “smoke” is produced later, following full bloom. Lawns are green. (Hanson is at 860 GDD, (Growing Degree Days), Base 40)

Pests/Problems: Winter moth caterpillars are in 4th and mostly 5th instar and have started to pupate and should soon be done feeding for the season. Throughout the winter moth season, except on roses, it has been difficult to find many winter moth caterpillars while scouting. The population was very low this year and damage from winter moth caterpillars appears minimal in many areas.

Gypsy moth caterpillars are actively feeding and were observed to be at 2nd, mostly 3rd and some 4th instars. They are feeding on a wide variety of deciduous material, but seem very fond of Fothergilla and Hamamelis, along with oak, crabapple, apple, etc. Gypsy moth caterpillar feeding activity appears scattered. In one area in Hanson, the gypsy moth caterpillars were in high numbers on many oaks. In another area, there were hardly any. There was significant damage high in the canopies of sugar maple and oak in some areas, but it is difficult to determine what is or what was causing it. Gypsy moth caterpillars will continue to feed for the next few weeks, and that is when damage should become evident. Cool, wet weather has been conducive to the formation of the caterpillar-killing fungus, Entomophaga maimaiga, and a few fungus-killed caterpillars were observed. Hopefully, these numbers will increase over the next 2-3 weeks, as the gypsy moth caterpillars continue to feed and grow.

Tiny nymphs ofAndromeda lacebug are actively feeding on the undersides of foliage of Japanese andromeda (Pieris japonica). Monitor or inspect Pieris japonica plants showing damaged foliage from last year. Look for bronzy-yellow stippled foliage on the upper leaf surface and then look beneath for the tiny small lacebugs. https://ag.umass.edu/landscape/fact-sheets/andromeda-lacebug. Rhododendron lacebugs are also active. Inspect rhododendrons showing damaged foliage from last year. Look for bronzy-yellow stippled foliage on the upper leaf surface and then look beneath for the tiny small lacebugs. Cottony camellia scale (also known as Cottony Taxus Scale) is active on Taxus and Meserve hollies. Inspect stems and the undersides of foliage for the white cottony egg masses. In heavy infestations, you may also see black sooty mold and yellowing foliage.

Monitor Siberian iris, Iris pseudacorus and bearded Iris for the small white maggot of the Orthacheta Bud Fly, sometimes referred to as the Iris bud fly. The maggots feed in the developing buds, and the emerging flowers appear tattered. The maggots feed down into the base of the flower then into the stem. Not much can be done to prevent this damage now, but removing and destroying the newly damaged flowers and stems may help to manage it for next year.

Euonymus caterpillar (cream colored with black spots) is active. Look for leaves webbed together near the tips of branches as the caterpillars feed and web the new foliage together. The webs are small now, but will grow in size as the caterpillars feed and develop.

Asiatic garden beetles, have started to emerge. These small copper-colored beetles feed at night on herbaceous and woody plant foliage.

Roseslug sawfly remains active on roses and if left untreated, the sawfly larvae will skeletonize the rose foliage. Bt (Bacillus thuringiensis) is not effective on sawflies. Azalea sawfly remains active on deciduous azaleas like Exbury and Weston hybrid summer flowering azaleas and foliar damage is now apparent.

With all the wet weather, mosquitoes are numerous this year. Remind clients to empty containers of water to help prevent breeding and consider using Bti (Bacillus thuringiensis israelensis) in birdbaths, plant saucers, etc.

The following insects remain active: European pine sawfly, lily leaf beetles, elongate hemlock scale, aphids, hemlock woolly adelgid, spruce spider mites, spittlebugs, deer tick nymphs, dog ticks, biting flies, carpenter ants, azalea whitefly, snails, woolly beech aphid, ants, wasps, hornets, carpenter bees, and bumblebees. Beneficial insects are active and so far, it appears to be a good year for swallowtail butterflies.

Deer tick nymph season is here and there are many ticks out there! This is the stage often thought to be most responsible for transmitting Lyme disease. Take precautions and conduct tick checks frequently.

Again, blame all the wet weather, but foliar diseases are making their appearance: apple scab on apples and crabapples; leafspots on dogwoods; Monilinia (brown rot) on Kwanzan cherry, and anthracnose on sycamore and dogwood.Shiny green galls of the fungal disease, Azalea leaf gall (Exobasidium vaccinii) have started to show up on deciduous azaleas; hand-pick and destroy the galls before they turn white.Phyllosticta hamamelidis (Witchhazel blight), a fungal disease, is showing up on thefoliage of ‘Arnold Promise’ witchhazel. Look for irregular shaped brown splotches. http://extension.illinois.edu/hortanswers/detailproblem.cfm?PathogenID=54

More and more Eastern white pines appear to be turning brown and not doing well. See the White Pine Needle Damage report in the disease section of the May 12, 2017 Landscape Message.

The following weeds are in bloom: ground ivy, oxeye daisy, cinquefoil, narrowleaf plantain, buttercups and veronica.

North Shore (Beverly)

General Conditions: The weather during this reporting period was mostly cloudy and overcast with occasional rain showers. Approximately 0.76 inches of rain was recorded at Long Hill. Temperatures were unseasonably cool for this time of the year, feeling like early spring rather than the unofficial start summer. Day temperatures ranged from the mid 50s to mid 60s and night temperatures ranged from the high 40s to low 50s. The highest temperature was 67° F recorded on May 28 and the lowest temperature was 48° F recorded on three days: May 25, 29 and 30. We gained 31 growing degree days during this reporting period. Woody plants seen in bloom include: Horsechestnut (Aesculus hippocastanum), Sapphireberry (Symplocos paniculata), Large leaf dogwood (Cornus macrophylla), Fragrant snowbell tree (Styrax obassia), Chinese Neillia (Neillia sinensis), Wisteria (Wisteria floribunda), Tree wisteria (Wisteria longissima alba), Slender Deutzia (Deutzia gracilis), Fringe tree (Chionanthus virginicus), American cranberrybush viburnum (Viburnum trilobum), Doublefile viburnum (Viburnum plicatum var. tomentosum), Constellation Rutgers dogwood (Cornus x rutgersensis), Tree peony (Paeonia suffruticosa), Umbrella tree (Magnolia tripetala), Redvein enkianthus (Enkianthus campanulatus), Vanhoutte spirea (Spirea vanhouttei), Little leaf lilac (Syringa microphylla), Beautybush (Kolkwitzia amabilis), Japanese wisteria (Wisteria floribunda), Toucan Azalea (Rhododendron ‘Toucan’, Palestrina Azalea (Rhododendron palestrina), Flame azalea (Rhododendron calendulaceum), Snow azalea (Rhododendron mucronatum), Hinodegiri azalea (Rhododendron hinodegiri), Nova Zembla Rhododendron (Rhododendron ‘Nova Zembla’, Golden chain tree (Laburnum anagyroides), Scotch Laburnum (Laburnum alpinum) and Singleseed hawthorn (Crataegus monogyna). Some of the non-woody plants seen in bloom include: Fetterbush (Leucothoe fontanesiana), Scotch rose (Rosa spinosissima), Peony (Paeonia sp.), Cranesbill (Geranium sp.), Bleeding heart (Dicentra spectabilis), Solomon’s seal (Polygonatum odoratum), Blue star (Amsonia hubrichtii), and several annuals.

Pests/Problems: Viburnum leaf beetles were observed skeletonizing leaves of American cranberrybush viburnum and Arrowwood viburnum. Doublefile viburnum doesn’t seem to be affected by the viburnum leaf beetle. Eastern tent caterpillar webs were also observed on branches of crabapples and cherry trees. They are ballooning and feeding on the leaves. Invasive plant species observed in flower include Autumn olive (Elaeagnus umbellata) andBurning bush (Euonymus alatus). Seedlings of Norway maple (Acer platanoides) were observed sprouting in the landscape. Weeds observed in flower include: Dandelion (Taraxacum officinale), Ground ivy (Glechoma hederacea), Garlic mustard (Alliaria petiolata), Deadnettle (Lamium purpureum), common chickweed (Stellaria media) and Common groundsel (Senecio vulgaris). Mosquitoes and ticks are very active. Protect yourself with a repellent when working outdoors.

East Region (Boston)

General Conditions: May temperatures have been below average. Over the last week, low temperatures have ranged from 48° F to 54° F averaging 50° F and high temperatures have ranged from 54° F to 72° F averaging 61° F. Memorial Day was chilly, we only reached a high of 54° F. Soils are plenty moist. We received precipitation on three days, the majority falling on the 25th and 26th accounting for 1.4 inches. We gained 39 GDDs for a total of 369.5 GDDs this year. The landscape is lush and turf is green; plants continue to flourish. Plants in bloom include: Chionanthus retusus (Chinese fringetree), C. virginicus (white fringetree), Cornus kousa (Kousa dogwood), Cornus poliophylla (dogwood), Crataegus sp. (hawthorn), Hyacinthoides hispanica (Spanish bluebell), Laburnum anagyroides (goldenchain tree), Paulownia tomentosa (princess tree), Philadelphus pekinensis (Peking mockorange), Photinia sp. (photinia), Potentilla fruticosa ‘Pumila’ (potentilla), Rhododendron calendulaceum (flame azalea), Rhododendron x gandavense ‘Lelia’ (Ghent hybrid azalea), many Rhododendron sp. (rhododendron) cultivars, Rosa foetida bicolor (Austrian copper rose), R. rugosa (beach rose), R. spinosissima (Scotch rose), R. zalana, Sophora davidii (David's mountain laurel), many Spiraea sp. (spirea), Styrax obassia (fragrant snowbell), Viburnum plicatum (Japanese snowball viburnum), V. plicatum ‘Mariesii’ (Maries doublefile viburnum), V. plicatum f. tomentosum (doublefile viburnum), and Weigela hortensis (gardeners weigela). While most lilacs have finished flowering, the following late blooming lilacs are putting a show: Syringa josikaea (Hungarian lilac), Syringa patula ‘Miss Kim’ (Miss Kim Manchurian lilac) and Syringa (villosa group) ‘Mary C. Bingham’ (lilac). The fruiting bodies of the saprotrophic Xylaria polymorpha (dead man’s finger fungus) are just beginning to form on decaying hardwood stumps.

Pests/Problems: Unwanted vegetation is thriving with the abundance of recent rainfall. Urtica dioica (stinging nettle) is 2 to 3 feet tall. Conyza canadensis (horseweed) is having a banner year in mulched beds. Woody weeds in natural wooded areas are flowering: Elaeagnus umbellata (autumn olive), Euonymus alatus (burning bush), Lonicera spp. (honeysuckle), Rhamnus cathartica (common buckthorn), and Rubus sp. (brambles).

Metro West (Acton)

General Conditions: We experienced early spring-like temperatures rather than late spring like temperatures during this reporting period. It was cooler more than it was warm, and windy or raining on any given day. The highest temperature recorded for this week was 77° on the 28th and the lowest temperature recorded was 46° on the 25th and 26th. The average monthly rainfall for May is 4.04” and as of the 30th I have recorded 4.76” and there is one rainy day to go. This is the second month in a row that we have exceeded the monthly rainfall average. Much is in bloom at this time of the year, including the following woody plants: Aesculus hippocastanum (Horsechestnut), Chionanthus virginicus (White Fringetree), Cornus florida (Dogwood), C. x rutgersensis 'Ruth Ellen' (Rutgers Hybrid Dogwood), Cornus sericea (Redosier Dogwood), Crataegus spp. (Hawthorn), Kerria japonica (Japanese Kerria), Leucothoe axillaris (Coast Leucothoe), Lonicera maackii (Amur Honeysuckle), Laburnum x waterii (Goldenchain Tree), Prunus serotina (Black Cherry), Rhododendron spp. (Azalea and Rhododendron), Robinia pseudoacacia (Black Locust), Rosa rugosa (Japanese Rose), Rubus spp. (Bramble, Blackberry), Sorbus aucuparia (European Mountain Ash), Spiraea spp. (Bridal Wreath), Syringa spp. (late blooming Lilac), Viburnum plicatum var. tomentosum (Doublefile Viburnum), V. sargentii (Sargent Viburnum), and Weigela florida (Old Fashioned Weigela). Woody vines in bloom are: Lonicera sempirvirens (Trumpet Honeysuckle), Clematis spp. (Clematis), and Wisteria spp. (Wisteria). Contributing even more color and interest to the landscape are some flowering herbaceous plants and spring ephemerals including: Actaea pachypoda (White Baneberry), Ajuga reptans (Bugleweed), Alchemilla mollis (Lady’s Mantle), Allium spp. (Ornamental Flowering Onion), Amsonia hubrichtii (Arkansas Blue Star), Aquilegia spp. (Columbine), Baptisia australis (False Blue Indigo), Bergenia cordifolia (Pigsqueak), Camassia scilloides (Wild Hyacinth), Cerastium tomentosum (Snow in Summer), Chrysogonum virginianum (Green and Gold), Convallaria majalis (Lily of the Valley), Cypripedium parviflorum (Yellow Lady's Slipper), Dianthus deltoides (Maiden Pink), Dicentra eximia (Fringed Bleeding Heart), D. spectabilis (Old Fashioned Bleeding Heart), D. spectabilis 'Alba' (White Flowering Old Fashioned Bleeding Heart), Dictamnus albus (Gas Plant), Gallium odorata (Sweet Woodruff), Geranium maculatum (Wild Geranium), G. macrorrhizum (Bigroot Geranium), G. sanguineum (Cranesbill Geranium), Hemerocallis spp. (early flowering Daylily), Hyacinthoides hispanica (Wood Hyacinth), Iberis sempervirens (Evergreen Candytuft), Iris germanica (Bearded Iris), I. sibirica (Siberian Iris), Linaria annua (Money Plant), Lupinus' 'Russell Woodfield Hybrids' (Lupine), Maianthemum dilatatum (False Lily of the Valley), Myosotis sylvatica (Forget-me-not), Nepeta spp. (Ornamental Catmint), Paeonia spp. (Peony), Papaver orientale (Poppy), Phlox divaricata (Canadian Phlox), P. stolonifera (Creeping Phlox), P. x subulata (Moss Phlox), Podophyllum peltatum (Mayapple), Polemonium reptans (Jacob’s Ladder), Polygonatum commutatum (Great Solomon Seal), P. odoratum 'Variegatum' (Variegated Solomon Seal), Salvia nemerosa (Salvia), Saponaria ocymoides (Rock Soapwort), Silene latifolia (White Campion), Stylophorum diphyllum (Wood Poppy),Thymus praecox (Thyme), Tiarella cordifolia (Foam Flower), Veronica umbrosa 'Georgia Blue' (Speedwell), Vinca minor (Periwinkle), Viola spp. (Violet), and Zizia aptera (Heart-Leaved Alexander).

Pests/Problems: Observed in the landscape this past week were the following: Winter moth caterpillar feeding on the foliage of Acer (Maple) and Quercus (Oak); Gypsy moth caterpillars feeding on Acer (Maple), Corylus (Filbert), Fagus (Beech), Malus (crabapple), Prunus (Cherry), Quercus (Oak), Ostrya (Hophornbeam) and Ulmus (Elm); and Woolly Beech Aphid on the underside of European Beech leaves. Many weeds continue to flower including some of the most invasive: Alliaria petiolata (Garlic Mustard), Elaeagnus umbellata (Autumn-olive), Euonymous alatus (Burning Bush), Lonicera maackii (Amur Honeysuckle), and Rhamnus cathartica (Common Buckthorn). Other weeds seen in bloom are: Glechoma hederacea (Ground Ivy), Lamium purpureum (Purple Deadnettle) and Taraxacum sp. (Dandelion). Toxicodendron radicans (Poison Ivy) continues to leaf out and it is fairly easy to detect its shiny red leaves of three. Ticks, mosquitoes and black flies are feeding and active.

Central Region (Boylston)

General Conditions: Another cool, damp reporting period has passed. Rainfall has been plentiful and soils remain quite wet. The cooler temperature continue to contribute to a long bloom season for spring trees, shrubs and herbaceous plants. Currently in bloom: Korean Abelia (Abelia mosanensis), Little Epaulette tree (Pterostyrax hispida), Beautybush (Kolkwitzia amabilis), Weigela, Black Locust (Robinia pseudoacacia), R. hispida, Enkianthus campanulatus, Cotinus obovatus, Rhododendron catawbiense, Rhododendron prinophyllum, Bridal Wreath Spiraea (S. vanhouttei), Syringa ‘Miss Kim’, S. meyeri, Calycanthus ‘Hartlage Wine’, Calycanthus floridus, and Magnolia ‘Yellow Bird’. Viburnum plicatum v. tomentosum, Rosa rugosa, and Sorbus aucuparua are also in bloom. Herbaceous plant include Aquilegia cvs., Pulmonaria cevennensis, Paeonia ‘Illini Belle’, Dodecatheon meadia, Maianthemum canadensis, Polygala paucifolia, Geranium maculatum, Geranium macrorrhizum, Erigeron pulchellum, Viola pedata, Convallaria majalis, and Amsonia tabernaemontana, among others.

Pests/Problems: Lily leaf beetle adults are active and mating, gypsy moth caterpillars are feeding on oak, apples and crabapple (Malus), Witchhazels (Hamamelis cvs). Birch (Betula), and numerous other plants. Spittlebug is evident in field grasses, Phlomis, and Galium. Columbine leaf miner damage is showing up. The current weather is conducive to rampant weed growth in open soils. Common and spotted asparagus beetles have been observed.

Pioneer Valley Region (Amherst)

General Conditions: Cool, cloudy and rainy best describes this past reporting period in the Pioneer Valley. Below-average temperatures predominated for most of the week with a seemingly endless streak of cloudy days and rain showers. A large storm system dumped up to and over 2″ of rain at many weather stations starting on the evening of Thursday, May 25 and persisting through Friday, May 26. This last major rain event capped off a very wet two months in the region, with April and May precipitation totaling 12″ in Easthampton and over 14″ in Greenfield. Over this 61-day stretch, there has been measurable precipitation on 31 days. Earlier this year, we were hoping for a wet spring and we got one. Soils remain moist but workable and conditions have been very good for transplanting trees and shrubs and establishing turfgrass. Advise clients to water recent transplants but stress the adverse effects of over-watering as well. Yews and rhododendrons are frequently overwatered after transplanting and stunted growth, yellowing foliage and edema often develops as a result. Most plants could use more sun and an increase in soil temperatures at this time, but overall the landscape is thriving with the abundant rain. Red maple, silver maple, katsura, linden, elm and crabapple are just some of the trees with indeterminate growth rates that are continuing to produce new foliage. This is good news for crabapples, as apple scab has caused premature shedding of the season’s oldest foliage. While oaks exhibit determinate growth, we can expect an additional flush from trees in good health (known as lammas growth). The long-term forecast calls for additional rainfall, so it appears that the calendar change to June will do little to alter the current weather patterns. Cottonwood seed continues to rain down throughout the valley in almost comical volumes.

Pests/Problems: Sycamore and plane trees are still having trouble leafing out, indicative of the wet weather and actions of the sycamore anthracnose pathogen. Maple anthracnose on sugar and red maple is widespread and destructive in some cases. Several opportunistic stem cankering fungi are sporulating on blighted shoots and stems, so sanitize pruners between shrubs and trees to limit spread. Spruce spider mites are actively feeding, so continue to scout for the flecking symptoms on interior branch needles and fine webbing they produce. Unlike many spider mites, the spruce spider mite prefers cooler conditions. Leaf rollers and gypsy moth feeding continue to be a problem in eastern Hampshire and Hampden Counties. Applications of appropriate insecticides (e.g. Bt) should be made to high-value trees and shrubs experiencing defoliation. The dry conditions in 2016 contributed to very high populations of lacebugs on Andromeda, azalea and rhododendrons. Treatment may be necessary on shrubs this year due to the severity of last year’s infestations. White pines continue to shed 2016 and 2015 needles (if the latter were even present to begin with). Previous research has shown that above-average rainfall in May, June and July corresponds to higher rates of the needle blight the following year. The high rainfall this May suggests that 2018 could be another bad year for white pines.

Berkshire Region (Great Barrington)

General Conditions: While night time temperatures were in the normal range of upper 40s to low 50s for the past week, day time temperatures were well below the normal of 70° F for this time of year with high temperatures mostly in the mid to upper 50s. Most days were cloudy with some rain though total rainfall for the period was not excessive. Overall, it was a cool and damp period - great weather for extending the bloom time for spring flowering plants and for survival of newly planted landscape specimens. However, soil moisture levels are high enough that tilling soils is not advisable except for well-drained soils. Turfgrass is growing rapidly. Despite a couple of warm days ahead, the forecast is for more of the same, that is, cool, damp weather. As of May 31, precipitation for the year to date is about 1.5 inches above normal and 4.25 inches more than last year, a drought year. There appears to be minimal winter related problems with plant development. Leaf and flower bud development have been normal and there are very few examples of twig dieback on woody plants.

Pests/Problems: The damp weather pattern has encouraged growth in the population of slugs, which are feeding on many annual flower transplants as well as some established herbaceous perennials.

Boxwood psyllids are still in the nymph stage but are more apparent than previously as the mass of waxy filaments surrounding the nymphs has increased. Boxwood leaf miners are in the adult stage. The adults are yellowish orange gnat-like flies. Their presence can easily be determined by brushing boxwood shrubs with your hand. This disturbance prompts the flies to flit above the shrub. The female flies will now lay eggs in the new growth on boxwood.

Woolly beech aphids continue to be active and are exuding sugary honeydew as they suck sap from the leaves of beech. This sticky honeydew serves as a medium in which a dark fungus, sooty mold, will grow. Though messy, this aphid does not cause much damage to host trees, other than interfering with photosynthesis in the leaves due to the sooty mold covering the foliage. Another woolly aphid, just found this week on the leaves of serviceberry (Amelanchier), is most likely the wooly elm aphid. The primary host of this aphid is elm but serviceberry is a secondary host.

Ongoing pest problems include: lily leaf beetle (adults), leaf beetle (larvae), imported willow leaf beetle (larvae), spruce spider mites on spruce, pear blister mites, four-lined plant bug (nymphs), spittlebug on herbaceous plants, forest tent caterpillar, leaf tiers and leaf rollers.

Reports of deer ticks relocating to humans working or otherwise venturing outdoors continue to increase. I have not seen any data on numbers of tick-related illnesses, but if the number of tick bites reported is any indication, it can be expected that there will be numerous cases during the summer.

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:

Stem cankering caused by Cytospora on Cotoneaster. Shrub is 15-years-old and has been present at the site for nearly as long. Blighted shoot tips were abundant throughout the canopy, but new growth appeared healthy at the base of the plant. The setting affords full sun but the shrub was planted on the corner of a driveway where snow is piled during the winter.

Severe infestation of the spruce spider mite (Oligonychus ununguis) and moderate infestation of the eastern spruce gall adelgid (Adelges abietis) on Norway spruce (Picea abies). Tree is 50-years-old and receives full sun with some supplemental water from lawn sprinklers. However, soils are sandy is the tree is roadside. Interior branches are yellowing and shedding large volumes of needles. Numerous adult mites, webbing, cast skins and eggs were found on the infested, yellowing needles.

Needle blight of eastern white pine (Pinus strobus) caused by Septorioides strobi. Four trees on the site, approximately 40-years-old, planted in full sun and provided with supplemental water through drip irrigation. One of the four trees has lost almost all of its older needles and Septorioides was abundant on the blighted needle tips, along with numerous saprophytic fungi.

Bacterial blight, caused by Pseudomonas syringae, on lilac (Syringa vulgaris ‘Ludwig Spaeth’). One-year-old, nursery plant watered via overhead sprinklers. The youngest leaves were distorted and cupped while brown spots with yellow halos were present on older leaves. Bacterial streaming was observed from the necrotic leaf spots. Culturing confirmed the presence of Pseudomonas, which produces bacterial colonies that fluoresce under ultraviolet light.

Needle and shoot blight of cryptomeria (Cryptomeria japonica) caused by Pestalotiopsis. Several trees, approximately 20-years-old, planted in two tight rows to provide border screening, which is an unusual application for this tree species. Apparently, the trees were transplanted from another site roughly 10 years ago and decline was observed only within the past two years. Serious canopy dieback and needle browning is present at this time, especially on the interior where the two rows of trees meet. Pestalotiopsis was abundant on the blighted shoots and needles and is common on this host in general. The fungus produces blacked tendrils of distinctive spores from dead shoots and needles.

Tubakia leaf blotch, caused by Tubakia dryina, on red oak (Quercus rubra). Tree is eight-years-old and was planted in mid-May. Upon flush, leaves curled and wilted. Regular watering was performed after planting and the tree resides in full sun. Symptoms from infection by Tubakia often do not appear until late June onward in southern New England but the tree was purchased from the mid-Atlantic where the disease appears earlier in the season. Infections develop in the spring but symptom development usually takes several weeks to months to manifest. The abundant rains and shock of transplant likely contributed to the early appearance of symptoms.

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

Insects

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

  • Gypsy moth caterpillars observed on 5/31/17 in Amherst. Caterpillars are mostly in the 2nd and 3rd instar in this location, however some 4th instar caterpillars may be observed as pictured here (furthest to the left). Note the color change in the head capsule – going from all black to black mottled with yellow. These larger caterpillars with the yellow mottled head capsule are much less susceptible to Btk. Spinosad will manage both smaller and larger gypsy moth caterpillars. (Simisky, 2017) Gypsy Moth: Lymantria dispar caterpillars are in various sizes or developmental stages (instars) depending upon the location in Massachusetts. A visit to Wellesley and Holliston, MA on 5/30/17 at certain locations showed smaller gypsy moth caterpillars than what has been recently observed in Amherst, MA. Monitor local gypsy moth caterpillars and look for tattered host plant foliage with young, ever growing gypsy moth caterpillars feeding beneath. These larvae will continue to feed for the next couple of weeks, until they typically pupate at the end of June. It is this month that the defoliation they cause will be most noticeable. If you find a host plant leaf with tattered holes in it, flip the leaf over and you may find roughly ½ - ¾ -inch long gypsy moth caterpillars feeding on the leaf underside. Some caterpillars are now approaching 1-inch in length in Amherst. These caterpillars are dark in color and hairy. Based on observations at a single location in Amherst, caterpillars are still mostly in the 2nd and 3rd instar stage (at that location). However, in Amherst, the “warts” of some of the gypsy moth caterpillars are developing to include the characteristic blue and red coloration. The color development of these spots will continue as caterpillars develop into the 4th instar, when blue and red spots/warts will be visible, along with a head capsule that is yellow mottled with black markings. A few 4th instar larvae were observed in Amherst on 5/31/17. Larval instars seen locally will vary depending upon how warm or cool the site is. See the Regional Reports above for more information about gypsy moth activity.

We need the cool and rainy conditions that we have been experiencing to continue through June, to help facilitate the successful infection of younger gypsy moth caterpillars with the insect-killing fungus Entomophaga maimaiga. It is important to note that even with fungal infection in the caterpillars, we may still see significant defoliation in certain areas of Massachusetts this year due to this insect. Dr. Joseph Elkinton and his lab group along with other local cooperators are currently embarking upon a study that he is referring to as the “Cloud of Death Experiment”! What Dr. Elkinton means by this is that the research will detect the amount of air-borne spores of the Entomophaga maimaiga fungus in certain locations of Massachusetts throughout the rest of the 2017 caterpillar activity (roughly through June). He and his lab hope to compare this to a measurement of the caterpillars killed at these various locations while determining if the fungus is responsible. Look to the Landscape Message for continued updates about Dr. Elkinton’s research concerning the activity of Entomophaga maimaiga in Massachusetts and what that might mean for gypsy moth.

This fungus overwinters in the soil litter in tough, protected asexual resting spores, which can survive in this state for years. Having lacked much precipitation most recently during the springs of 2015 and 2016, it is thought that our current expanding populations of gypsy moth are at least in part a result of a lack of infection in the caterpillar population by this fungus. Hopefully Massachusetts will continue to see more rainfall through June.

To treat individual, landscape ornamental and shade trees using the active ingredient Btk (Bacillus thuringiensis Kurstaki) for gypsy moth, be sure that the newly hatched caterpillars have settled to feed on fully expanded foliage and are roughly between ¼ - ¾ inch in length. Larger caterpillars (over ¾ inch) are less susceptible to Btk. (In some locations, gypsy moth caterpillars are growing larger than ¾ inch at this time and therefore will be less susceptible to Btk. Local monitoring is very important when making decisions about what active ingredient to use, if choosing chemical management options.) These applications should be made when very young caterpillars are actively feeding on host plant leaves, as it must be ingested to be effective. Multiple applications of Btk may be necessary. Spinosad is effective on younger and older gypsy moth caterpillars (over ¾ inch in length) but should not be applied to plants while they are in bloom due to the risk toward pollinators.

Gypsy moth host plants include but are not limited to oak (favored), maple, birch, poplar, and many others. Caterpillars will feed on conifers (such as eastern white pine, hemlock, and spruce) when favored resources have been exhausted. (Note: winter moth and gypsy moth share some common host plants. Therefore, where populations of these two insects overlap in Massachusetts, the same tree may be defoliated by winter moth and then again by gypsy moth following in the same season.) Caterpillar dispersal occurs earlier in the season by crawling to the canopy of their host plant, where they can scatter using a technique known as “ballooning”. 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, however egg masses may be present on nearby oaks, for example, and provide a local population of caterpillars.

Patchy areas across mostly central and eastern Massachusetts experienced elevated populations of gypsy moth and significant amounts of defoliation in 2016 (see the Insects section of the archived 2016 Landscape Messages between April 29 and July 29). The Massachusetts Department of Conservation and Recreation aerially mapped approximately 350,000 acres of defoliation across Massachusetts last year, attributed to gypsy moth. State officials warn the public about another year of defoliation from gypsy moth as predicted for 2017: http://www.mass.gov/eea/agencies/dcr/pr-2017/another-year-of-defoliation-from-gypsy-moth-in-2017.html. That web page also links to a map of the 2016 defoliation from gypsy moth, which may provide a reference regarding areas that may be impacted by this insect again in 2017.

We can also hope areas in Massachusetts that did not experience much gypsy moth defoliation last year (areas such as most of Berkshire County) will be mostly spared in 2017 in comparison to those areas who suffered last year in southern central and eastern Massachusetts. However, due to the ballooning ability of the young caterpillars, where egg masses may exist nearby, previously unaffected host plants may be found to have gypsy moth caterpillars present on them this year. For more information about gypsy moth, please visit: http://ag.umass.edu/landscape/fact-sheets/gypsy-moth and return to the Landscape Message for timely updates about this pest and others throughout the season. An excellent article written by Dr. Joseph Elkinton and Jeff Boettner of the University of Massachusetts about the 2016 outbreak and the history of this insect in Massachusetts may be found here: http://www.mass.gov/eea/agencies/dfg/dfw/publications/gypsy-moth-outbreak-of-2016.html.

Reports continue to indicate that in most areas this year, winter moth caterpillar numbers are reduced. See Regional Reports above for updates regarding current winter moth activity. Dr. Joseph Elkinton and his lab team at the University of Massachusetts report that as of 5/30/17, late instar winter moth caterpillars are still active in certain locations on Cape Cod (Eastham; although the winter moth population density at this site is very low) and the North Shore (Wenham) of Massachusetts. It is typical for these more coastal locations to be behind eastern MA locations that are a bit more “inland”. (Relatively speaking.) Winter moth densities were also observed to be very low this week at a location in Brewster, MA; however, at the same location, gypsy moth densities are very high. At a relatively “inland” location in Wellesley, MA, the Elkinton Lab collected 300 winter moth caterpillars the week of 5/22/17. As of 5/30/17, only a single winter moth larva was found using the same sampling techniques at the same location in Wellesley. It is thought that pupation of winter moth has begun at that location, and is likely also occurring at sites in eastern MA away from the coast. Once pupation of winter moth has begun, management of this insect is no longer warranted or possible at that time. Winter moth feeding activity for the 2017 season will soon be at an end.

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 the newly updated (March, 2017) fact sheet: Winter Moth in Massachusetts: History and Biological Control (https://ag.umass.edu/landscape/fact-sheets/winter-moth-in-massachusetts-history-biological-control).

This fact sheet also includes updates regarding the progress of the work of Dr. Joseph Elkinton’s laboratory group at the University of Massachusetts and their efforts towards the biological control of winter moth using Cyzenis albicans, a tachinid fly. The fly parasitizes the caterpillars of winter moth specifically. In other areas, such as Nova Scotia where winter moth was also problematic, this fly used for biological control has been successful in reducing winter moth to a non-pest. C. albicans has been released across 41 sites in Massachusetts and has been established in at least 17 of those sites as evidenced through the recovery of flies in winter moth in subsequent years. In one site in Wellesley, these flies have been observed to be spreading from the initial release location and their populations have increased alongside an observed decrease in the winter moth population there. For more information, please visit the above mentioned fact sheet.

  • Azalea bark scale observed on 5/31/17 in Amherst. (Simisky, 2017) Azalea Bark Scale: Eriococcus azaleae was discovered in CT in 1917 and has since been reported in other states. It is found on the bark of twigs and stems and commonly settles in branch crotches. It has been reported on azalea, rhododendron, andromeda, and others. Female scales are approximately 2-3 mm. in length and covered in a white, waxy coating. The females are purple in color and may resemble a mealybug, although they are a soft or felt scale. These females have overwintered and are going to lay eggs which will hatch into crawlers toward the end of June through mid-July. Crawlers will settle into branch crotches, bark crevices, or on the axils of leaves. There is a parasitic wasp that will attack these insects. When high in number, these scales can cause yellowing of the foliage and their sugary excrement can lead to the promotion of sooty mold. Because these are soft scales, they may be targeted with horticultural oils or insecticidal soaps while observing label instructions to prevent phytotoxicity.
  • Black Vine Weevil: Otiorhynchus sulcatus damage is apparent on rhododendron and taxus, but can also be seen on azalea, mountain laurel, and Euonymus. Adult weevils feed along the leaf/needle margins and create rounded notches. Inspect foliage of these plants for notching from last season’s feeding. Larvae, which dwell in the soil, are pupating. Adults will emerge in June and create new damage to leaves for this season. All individuals are females and reproduce asexually. This insect has developed resistance to many chemical insecticides. Entomopathogenic nematodes such as Steinernema carpocapsae, S. feltiae, and Heterorhabditis bacterio-phora work well against this insect, particularly on containerized plants. Results in the landscape vary. Wetting the soil thoroughly prior to application and keeping it wet for at least 5 days following application can help increase the efficacy of the nematodes. Burlap laid around the base of plants during the time adults are active, through August, can be inspected weekly for adult weevils which can be killed before egg laying.
  • Boxwood Psyllid: Psylla buxi is feeding on boxwood foliage with its piercing-sucking mouthparts. This feeding may not cause yellowing or loss of foliage, but will lead to the cupping of new leaves which can be an aesthetic issue for some. If population numbers are low, management of this pest may not be necessary. Nymphs of this insect may be managed between 290-440 GDD’s.
  • Cottony taxus scale (also known as the cottony camellia scale) female with eggs observed on 5/31/17 in Amherst. Wondering what the creatures to the right are? Continue reading the Insects section. (Simisky, 2017) Cottony Taxus Scale: Chloropulvinaria floccifera, also referred to as the cottony camellia scale, utilizes such hosts as taxus, camellia, holly, hydrangea, Japanese maple, euonymus, magnolia, jasmine, and Callicarpa americana. This insect was observed on taxus in Amherst on 5/31/17. Females are laying the long, narrow, white colored egg sac that makes them much more noticeable. Eggs will hatch over an extended period of 6 weeks and crawlers may be treated between 802-1388 GDD’s. This insect can cause the host to appear off-color. They also produce honeydew which promotes sooty mold growth. Target the underside of the foliage. Horticultural oil, neem oil, and insecticidal soaps may be used to manage these soft scales. They may also be washed from plants with a strong jet of water.
  • Eastern Tent Caterpillar: Malacosoma americanum (ETC) tents are increasingly noticeable in certain areas of the state. Scout for, remove, and destroy any eastern tent caterpillar tents in the crotches of branches on susceptible hosts such as cherry and crabapple. Other host plants impacted by this native insect can include apple, ash, birch, willow, maple, oak, poplar, and witch-hazel. Pupation of this insect will begin in June and last for a few weeks. Adults are typically seen in late June - early July. For a photo demonstration on how to mechanically manage ETC, please visit the following Buckeye Yard & Garden onLine report from Joe Boggs of the Ohio State University Extension. Warning, reader discretion is advised: http://bygl.osu.edu/node/733.
  • 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.
  • European Pine Sawfly: Neodiprion sertifer caterpillar’s primary host in MA is Mugo pine but it can be found on Scots, red, jack, and Japanese red pine, but is also found on white, Austrian, ponderosa, shortleaf, and pitch pine when near the aforementioned species. This dark colored caterpillar feeds in tight groups and small numbers can be pruned away and destroyed. By June, these caterpillars will drop to the ground to pupate. Adults are typically active in early September through the fall.
  • Forest Tent Caterpillar: Malacosoma disstria (FTC) caterpillars continue to feed on maple and oak. Other susceptible hosts such as birch, ash, elm, poplar, and basswood may also be fed upon by these caterpillars. These native caterpillars can defoliate their host plants, but are not currently in large populations in all areas in the state. In 2016, certain forested locations in Berkshire County supported ample numbers of these caterpillars. Neighboring states also reported some increased activity by this native insect such as in Vermont (http://bit.ly/2qAoxkR) and New Hampshire (https://nhbugs.org/forest-tent-caterpillar). It will be interesting to keep an eye on the Massachusetts population.
  • 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 early June. Monitor susceptible hosts for small, inch-worm like caterpillars. Where populations are low, no management is necessary. Anecdotal reports of increasing hemlock looper populations in certain areas of western Massachusetts (Berkshire County) have been made this season.
  • Evidence of a leafrolling insect seen on witch hazel in Holliston, MA on 5/30/17. The larvae of many different moth families are known to behave in this manner. (Simisky, 2017) A photo of leafrollers on witch hazel seen in Holliston, MA. No less than two gypsy moth larvae “photobombed” the picture and their feeding is also evident. (Simisky, 2017) Leafrollers on Witch Hazel: Many different families of moths are known to be leafrollers of various deciduous hosts when in their larval or caterpillar life stage. Some families include but are not limited to the Tortricidae (tortrix moths or leafroller moths), Gelichiidae (twirler moths), Pyraustidae, and Pyralidae (pyralid moths or snout moths). Some species are significant pests in fruit crops. Two species that utilize witch hazel include Pandemis limitata and Episimus argutanus. P. limitata is sometimes referred to as the three-lined leafroller and can be found on witch hazel, willow, aspen, oak, apple, and birch. It is known to the northern United States and Canada. E. argutanus is very widespread throughout the USA and southern Canada and is commonly called the “sumac leafroller”, although it can also utilize witch-hazel and poison ivy as hosts. When leafrollers are small in number on ornamental plants, management may not be required.

     
  • Lily leaf beetle adult males and females are still seen together. The female is laying eggs in this photo taken on 5/31/17 in Amherst. (Simisky, 2017) Lily leaf beetle eggs continue to hatch and tiny excrement-covered larvae begin feeding by skeletonizing the underside of the leaf and can eventually defoliate the entire plant. As seen in Amherst on 5/31/17. (Simisky, 2017) Lily Leaf Beetle: Lilioceris lilii adult beetles were still causing feeding damage, mating, and eggs were laid on plants in Amherst on 5/31/17. More frass or excrement-covered larvae of this insect were also found feeding in Amherst at this time. See Regional Reports for local activity of this insect. Management can be achieved by hand-picking and removing adults and larvae. Some chemical management options are available for this insect, but if caught early mechanical management may be effective.

The University of Rhode Island Biological Control Lab is researching ways to find a natural method to combat these beetles. Small parasitic insects have been established in lily plots in Cumberland, RI and Wellesley, MA in hopes that these insects will disperse naturally to reduce the effects of the lily leaf beetle. If you have larvae in your yard (or a customer’s yard), please send to URI, following the instructions on the URI Biocontrol Lab website: http://web.uri.edu/biocontrol/home/lily-leaf-beetle-larval-collections-2016-mailing-instructions/
 

  • A multicolored Asian ladybeetle laying eggs as seen on 5/31/17 in Amherst. In the landscape, these “ladybugs” can be predators of aphids, mites, and thrips. Unfortunately, this species also likes to overwinter in homes. Although it is not a structural pest, it can be a nuisance indoors. (Simisky, 2017 Multicolored Asian Lady Beetle (Ladybug): Harmonia axyridis is a native of eastern Asia and was previously introduced into the USA as a biological control agent by the USDA. They tend to be larger than some of our native lady beetles and the adults have a characteristic black “M” shape (or “W” depending upon your viewing direction) on the white pronotum (plate-like structure that covers the thorax of some insects). Adults and larvae can be predators of certain aphids, mites, and thrips. In the landscape, this insect can be considered a natural enemy of pests. This species can be annoying to some in the fall and winter, when the adults will sometimes gather in homes and other indoor structures in large amounts. They do not cause structural damage in the home, but can be annoying home invaders when they seek overwintering shelter.
  • Roseslugs: Two species of sawfly can be found on the leaves of roses at this time. These small, caterpillar-like larvae will skeletonize the upper leaf surface and leave a “window-pane” like pattern behind. When present in large numbers, these insects are capable of defoliating their entire host. Management options include an insecticidal soap spray or a product containing spinosad.
     
  • A group of taxus mealybugs on yew as seen in Amherst on 5/31/17. The cottony taxus (camellia) scale is to the left in the photo. (Simisky, 2017) Taxus Mealybug: Dysmicoccus wistariae was spotted on taxus in Amherst on 5/31/17. This insect will produce honeydew and lead to sooty mold growth, yellowing of needles, and sparsely foliated plants. Eventual dieback may be possible. This species is commonly associated with taxus in New England, but can be occasionally found on dogwood, rhododendron, Prunus spp., maple, andromeda, and crabapple. These mealybugs are found on stems and branches and particularly like to congregate at branch crotches. Management may be targeted between 246-618 GDD’s. Horticultural oil and neem oil may be used.



     
  • Two-marked tree hopper nymphs in Amherst are still very small as of 5/31/17 on wafer ash. Although plentiful, these insects typically do not require management. (Simisky, 2017) Two-marked Tree Hopper: The Enchenopa binotata species complex is now thought to be made up of very closely related Enchenopa spp. that are morphologically very similar but separated by the different host plants that they are found on. These particular treehoppers are found on black walnut, wafer ash (Ptelea trifoliata), and viburnum. These insects will feed on the host plants with piercing-sucking mouthparts and drink plant juices from the leaves and petioles. Leaves will become shiny and sticky with their excrement. Tiny nymphs have been observed on wafer ash in Amherst. Eggs are laid by adult females using saw-like ovipositors to insert them into plant stems. Eggs are then covered with a vivid white, sticky, frothy material that protects them but can easily be mistaken for a scale insect. Eggs have hatched and the tiny, young nymphs can be seen feeding at this time. These treehoppers, whether by their feeding activity or egg laying behavior into plant stems, are not considered to be damaging pests (even when high in numbers) and therefore management is generally not required.
  • Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. See the Regional Reports regarding areas where this insect has been noted to be active thus far this season. 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. Larvae 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/.
  • White Spotted Pine Sawyer (WSPS): Monochamus scutellatus adults have been reported from Middlesex and Worcester counties at this time. Adults are typically active at this time of year, through July, depending upon 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 below for more information about that non-native insect.
  • Chilli Thrips: *A non-native insect has been confirmed in Massachusetts for the first time.* The non-native, exotic chilli thrips (Scirtothrips dorsalis) has been recently 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) available on the UMass Extension Landscape, Nursery, and Urban Forestry Program web page.
  • 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. Adult insects of this species will not be present at this time of year.

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.

  • Emerald Ash Borer (EAB): Agrilus planipennis readily attacks ash (Fraxinus spp.) including white, green, and black ash and has also been found developing in white fringe tree (Chionanthus virginicus). Adult insects of this species will be emerging this season around 450 GDD’s (see Environmental Data above). 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 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 follow the instructions below.

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.

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 (www.tickdiseases.org) and click on the red Test a Tick button for more information.

For information about managing ticks in landscapes, among other topics, please visit the following publication from the Connecticut Agricultural Experiment Station: “Tick Management Handbook”: http://www.ct.gov/caes/lib/caes/documents/publications/bulletins/b1010.pdf.

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

Management Practices

Deutzia gracilis, slender deutzia Deutzia gracilis, slender deutzia Deutzia gracilis, slender deutzia Plant of the week: Deutzia gracilis, slender deutzia

Deutzia gracilis is a slow growing, small, mounded shrub growing 2-4’ tall and wide. Plants are most impressive in late May when they are covered in numerous racemes of small, white 5-petaled flowers. Blooms only last 1-2 weeks. Branches are arching and slender, providing the common name. The lanceolate leaves are 1-3” long and ½” wide with a pointed tip and unequal serrated margins. The species does not have good fall color. Plants should be sited in well-drained soil in full sun to part shade, with best flowering in full sun. Renewal pruning can help improve form and remove dead branches. Pruning should be after flowering in spring. Deutzia gracilis has no serious insect of disease problems but leaf spot, leaf miners, and aphids can sometimes occur. Slender deutzia is best planted for the flowering impact and can be used in the foundation planting, shrub border, or in groups. D. gracilis ‘Nikko’ is a common cultivar that grows to 2’ and has good red fall color. D. gracilis ‘Duncan’ (Chardonnay Pearls ®) has nice chartreuse foliage, grows 2-3’ tall, and pearl-like white flower buds that provide the trade name.

Report by Mandy Bayer, Extension Assistant Professor of Sustainable Landscape Horticulture, UMass Stockbridge School of Agriculture

Additional Resources

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For a complete listing of upcoming events, see our Upcoming Educational Events page.

For commercial growers of greenhouse crops and flowers - Check out the New England Greenhouse Update website

For professional turf managers - Check out Turf Management Updates

For home gardeners and garden retailers - Check out home lawn and garden resources. UMass Extension also has a Twitter feed that provides timely, daily gardening tips, sunrise and sunset times to home gardeners, see https://twitter.com/UMassGardenClip

Diagnostic Services

A UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see Plant Diagnostics Laboratory

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. Alternatively, call the lab at (413) 545-2311.

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