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Landscape Message: May 26, 2017

May 26, 2017
Issue: 
10

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 2. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

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


Scouting Information by Region

Environmental Data

The following data was collected on or about May 24. 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

81

233.5

66

59

1.01

12:00 PM 5/24

Southeast

78

252

67

60

0.26

5:15 PM 5/24

North Shore

101

286

57

53

0.18

9:30 AM 5/24

East

106

330.5

63

58

0.46

4:00 PM 5/24

Metro West

98.5

296

57

54

0.63

5:35 AM 5/24

Central

99

334

58

55

0.26

-

Pioneer Valley

90

304

61

57

0.47

11:30 AM 5/24

Berkshires

83

245

57

53

0.38

8:30 AM 5/24

AVERAGE

92

285

61

56

0.46

-

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.
Robinia pseudoacacia (Black Locust) * Begin Full Begin Begin/ Full * Full *
Kolkwitzia amabilis (Beautybush) * Begin Begin/Full Begin * Begin Full *
Weigela florida (Old Fashioned Weigela) * Begin * Begin/Full * Begin Full *
Deutzia spp. (Deutzia species) Begin Begin Begin Begin Begin Full Begin/Full Begin
Enkianthus campanulatus (Redvein Enkianthus) Begin/Full Full Full Full Full Full Full Begin/ Full
Rhododendron carolinianum (Carolina Rhododendron) Begin Full Full/End Full/End Begin/Full * Full *
Rhododendron catawbiense (Catawba Rhododendron) Begin Begin/Full Full/End Begin Begin/ Full Begin/Full Begin/Full Begin/Full
Spiraea x vanhouttei (Vanhoutte Spirea) Full/End Full Full * Full Full Full Full
Aesculus hippocastanum (Common Horsechestnut) Full Full Full Full Full Full Full Full
Elaeagnus umbellata (Autumn-olive) Full/End Full/ End Full/End Full/End Full/ End Full Full/End Begin/ Full
Syringa vulgaris (Common Lilac) End End Full/End End Full/ End Full/end Full/End Full/ End
Rhododendron spp. (Early Azaleas) Full/End Full Full Full/End Full/ End Full Full/End Full
Cornus florida (Flowering Dogwood) End End Full/End End Full/ End Full/end End Full/ End
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The average temperature over the last week was 61.5° F with a low of 39° F on May 21 and a high of 89° F on May 18. A total of 1.01 inches of precipitation fell over May 23 & 24. May 17, 18, & 19 had temperatures well above normal, followed by May 20-24 which had temperatures primarily in the 50s. May 22, 23 & 24 have been overcast. Soil moisture continues to be adequate.

Pests/Problems: Gypsy moth is the primary concern here. Caterpillars are actively feeding on hosts, caterpillars are about 1-1.5 cm in length. Winter moth also continues to feed on hosts, winter moth caterpillars are about 2 cm in length. Viburnum leaf beetle can be found feeding on the undersides of viburnum. Boxwood pysllid is still active. Boxwood leafminer has pupated and the midges can be found on boxwood. Columbine sawfly larvae can be found eating the leaves of columbine. European roseslug sawfly can found feeding on the undersides of rose leaves. Hydrangea leaftier, Olethreutes ferriferana, damage can be seen on Hydrangea arborescens. Sycamore anthracnose is causing significant blight on some sycamores. Weeds in bloom; Bulbous Buttercup (Ranunculus bulbosus), garlic mustard (Alliaria petiolata), Dandelion (Taraxacum officinale), Henbit (Lamium spp.), Speedwell (Veronica spp.), Mouse-ear chickweed (Cerastium vulgatum), Common violet (Viola papilionacea), Yellow rocket (Barbarea vulgaris), autumn olive (Elaeagnus umbellate), Honeysuckle (Lonicera spp.), Plantain (Plantago major & lanceolata). Nymph stage black legged ticks are around, keep yourself and others protected; Tick checks, permethrin-treated clothing/footwear and perimeter yard sprays.

Southeast Region (Hanson)

General Conditions: The weather began to warm up last week with a high of 93 degrees on May 18 and 91 degrees on May 19th. The warm weather pushed growth on plants and dried the soils out pretty quickly. Weather turned cooler (50’s) with slight rain and drizzle on May 22nd. Hanson received only 0.26 inches of rain last week and soils are dry in full sun areas and drying out in others. Remind clients to water newly planted plants and lawns. (Hanson has 707 GDD (Growing Degree Days) base 40).

The following plants are in full bloom: Rutgers hybrid dogwoods (Stellar series), Prunus serotina (black cherry), Aesculus hippocastanum (Common Horsechestnut), Magnolia fraseri, late blooming magnolias, Calycanthus floridus (Carolina allspice), Syringa sp., Lonicerajaponica (invasive), Wisteria floribunda (Japanese Wisteria), Kerria, numerous viburnums, includingViburnum plicatum f. tomentosum (Doublefile file viburnum), Aristolochia durior (Dutchman's pipe), Kerria, Cytisus scoparius (Scotch broom, Camassia sp., Persicaria bistorta ‘Superbum’, Corydalis lutea, Tiarella cordifolia (Foam Flower), Buglossoides purpurocaerulea, Geranium sp., Hyacinthoides hispanica, Convallaria majalis (Lily-of-the-valley), Epimedium sp., Cypripedium parviflorum (Yellow Lady’s Slipper), Trillium sp., Galium odoratum (Sweet Woodruff), Brunnera macrophylla, Polygonatum sp. (Solomon's Seal), Stylophorum diphyllum (Wood Poppy), Phlox subulata, Phlox stolonifera, Phlox divaricata, Arisaema dracontium, Arisaema ringens, and other Arisaema sp. (Jack-in-the-pulpit), Euphorbia polychroma, Doronicum sp., Ajuga, dwarf bearded Iris,Bearded Iris, Saruma henryi, Lamiastrum galeobdolon, Lamium sp., Aurinia saxatilis (Basket of Gold), Dicentra spectabilis, Lunaria annua (honesty or money plant), Mertensia virginica (Virginia bluebells), Aquilegia sp. (Columbine) Myosotis sylvatica (Forget-me-not) and Vinca minor . Many rhododendrons are in bloom and what a glorious year for them. With all the drought last year, this 2017 spring is surprisingly colorful. The flowering bracts of Kousa dogwood are beginning to open and show color, and the following plants are beginning to bloom:Chionanthus virginicus, Weigela florida, Indigofera sp., Anenome canadensis, Amsonia sp., Baptisia australis and Baptisia hybrids.

The following plants are ending bloom: Daphne x burkwoodii 'Carol Mackie', Daphne tangutica, Viburnum ‘Eskimo’, Viburnum setigerum, Fothergilla major (large Fothergilla), Fothergilla gardenii (dwarf Fothergilla), Arisaema sikokianum and Helleborus foetidus. Lawns are green and with all the previous rain, fertilized lawns are growing fast and furiously. If using a preventative grub management product that contains Chlorantraniliprole (AceleprynTM, GrubExTM), it is best applied before the end of May; follow the directions on the label before applying

Ilex opaca, American holly, is shedding its’ older, yellow leaves; not too worry, this is an annual event. Massachusetts invasive plants: barberry, autumn olive and burning bush, are in bloom. Where, and if, possible, now is a good time to remove and destroy the plants in landscapes and/or prune and shear them to remove flowers to prevent further seed production and dispersal.

Pests/Problems: Winter moth caterpillars remain active, although in low numbers in many areas, and are in 3rd and 4th instars. Also, in many areas, damage to foliage from winter moth caterpillar feeding is greatly reduced from previous years. Continue to monitor high value trees and shrubs and manage, if found. Gypsy moth caterpillars are small, mostly 2nd and 3rd instars and are active on a wide variety of plant material including Fothergilla, blueberries, roses, crabapples and apples, along with the usual hosts of oak, maple, etc. Manage early, while caterpillars are small and before damage is significant.

Roseslug sawfly is now active on roses. Monitor rose foliage for the small, slug-like, pale-green larvae, if left untreated, the sawfly larvae will skeletonize the rose foliage and the foliage will appear ‘burned’, resembling tan lace. Bt (Bacillus thuringiensis) is not effective on sawfly larvae, although insecticidal soap and products containing Spinosad are. Like most insecticides, do not apply Spinosad to plants that are in bloom, to avoid harming pollinators. Azalea sawfly larvae are now active on deciduous azaleas like Exbury azaleas. The small, bright glossy green caterpillar-like larvae are difficult to see and can often be found feeding on the outer margin of a leaf, feeding inward, leaving only the midvein; manage early to avoid defoliation.

Monitor the tips of Euonymus branches for webbing of the Euonymus caterpillar. The caterpillars feed and web the leaf tips together.

Lily leaf beetle adults, larvae and eggs are active on true lilies. Products that contain Spinosad are effective on the larvae but not on the adults. Handpick and destroy the adults when possible, or manage with a labeled insecticide.

The following insects are active: spruce spider mite; hemlock woolly adelgid; elongate hemlock (Fiorina scale); Eastern tent caterpillar; European pine sawfly; aphids, woolly beech aphid on beech; slugs, snails, ants, deer flies; wasps, hornets, mosquitoes,carpenter bees, dog ticks and deer tick nymphs; remember, the deer tick nymph stage is often thought to be most responsible for transmitting Lyme disease. Frequent tick checks are recommended for everyone working or playing outdoors, especially in grassy areas or areas with leaf litter. Good information to pass on to your clients. The wet weather has been has been conducive for disease: apple scab on apples and crabapples; leafspots on dogwoods; anthracnose on sycamore. Ground ivy, garlic mustard, hawkweed, buttercups, veronica, and chickweed are in full bloom. Deer, wild turkeys, and chipmunks continue to be a nuisance.

North Shore (Beverly)

General Conditions: The weather conditions during this reporting period were very variable. The early part of the reporting period was almost summer-like with temperatures getting up to the low 90s during the first three days. The second half of the reporting period was more seasonable with day temperatures in the low 60s and night temperatures in the mid 50s. We accumulated 101 growing degree days at Long Hill during this reporting period, and approximately 0.18 inches of rain were received. Lawns are green and there is plenty of color in the landscape. Several plants are either in full bloom or beginning to bloom. Woody plants seen in full bloom include: Common Horsechestnut (Aesculus hippocastanum), Flowering dogwood (Cornus florida), Golden chain tree (Laburnum anagyroides), Scotch Laburnum (Laburnum alpinum) Handkerchief tree (Davidia involucrata var. vilmoriniana), Wayfaring tree viburnum (Viburnum lantana), Doublefile viburnum (Viburnum plicatum var. tomentosum), Royal azalea (Rhododendron schlippenbachii), White Find rhododendron (Rhododendron vaseyi 'White Find'), Hallelujah rhododendron (Rhododendron ‘Hallelujah’), Hinodegiri azalea (Rhododendron ‘Hinodegiri’), Polar bear azalea (Rhododendron ‘Polar Bear’), Pink Shell azalea (Rhododendron vaseyi), Carolina Rhododendron (Rhododendron carolinianum), Catawba Rhododendron (Rhododendron catawbiense), Fothergilla (Fothergilla major) , Wisteria (Wisteria floribunda). Red horsechestnut (Aesculus x carnea), Single seed hawthorn (Crataegus monogyna), Wright viburnum (Viburnum wrightii), American cranberrybush viburnum (Viburnum trilobum), Little leaf lilac (Syringa microphylla) Percy wiseman rhododendron (Rhododendron ‘Percy Wiseman’), Scintillation rhododendron (Rhododendron ‘Scintillation’), Unique azalea (Rhododendron ‘Unique’), and Miss Louisa azalea. Herbaceous plants in bloom include: Solomon’s seal (Polygonatum odoratum), Honesty plant (Lunaria annua), Yellow archangel (Lamiastrum galeobdolon), Blue eyed Mary (Omphalodes verna), Vinca vine (Vinca major), Forget-me-not (Myosotis palustris), Barrenwort (Epimedium rubrum), Trilliums (Trillium spp.), Corydalis (Corydalis lutea), Bleeding heart (Dicentra spectabilis), Scotch rose (Rosa spinosissima), Father Hugo rose (Rosa hugonis), Fetterbush (Leucothoe fontanesiana), and Snowbells (Leucothoe racemosa).

Pests/Problems: Ticks and mosquitoes are very active. Make sure you apply repellents before going to work outdoors. Dandelion (Taraxacum officinale) seeds are maturing and are being blown over the landscape by wind. Other spring weeds are in bloom. Those seen in bloom include: Violets (Viola spp.), Ground ivy (Glechoma hederacea) Garlic mustard (Alliaria petiolata) and Dead nettle (Lamium purpureum). Take measures to control weeds before they set seed.

East Region (Boston)

General Conditions: It has been a typical New England spring, we have had various low temperatures, ranging from 43° F to 69° F, averaging 54° F. On May 17th, 18th, and 19th, we experienced a ‘technical’ heat wave equating to three consecutive days above 90°F, reaching 92° F, 96° F, and 90° F respectively. We gained 106 GDDs for a total of 330.5 GDDs for the year. We received rain on two occasions, a 0.25-inch downpour in the early morning of the 19th and a second all-day event on the 22nd. These extreme weather fluctuations along with the downpour have resulted in many plants in bloom having lost their petals, while many others have quickly come into bloom including: Acer spicatum (mountain maple), Aesculus x carnea 'Briotii' (ruby red horsechestnut), Allium giganteum (giant flowering onion), Carya tomentosa (mockernut hickory), Convallaria majalis (lily-of-the-valley), Cornus sericea (redtwig dogwood), Crataegus sp. (hawthorn), Fraxinus ornus (flowering ash), Geranium macrorrhizum (bigroot geranium), Ilex aquifolium (English holly), Laburnum x watereri (goldenchain tree), Leucothoe axillaris (coast leucothoe), Liriodendron tulipifera (tulip tree), Maianthemum canadense (Canada mayflower), Magnolia tripetala (umbrella magnolia), Mespilus germanica (common medlar), many Paeonia sp. (peony) cultivars, Paeonia suffruticosa (tree peony), Paulownia tomentosa (princess tree), Pinus mugo (mugo pine), Prunus serotina (black cherry), Rosa acicularis (prickly wild rose), Rosa amblyotis (erect prickle rose), Rosa nutkana (bristly rose), Rosa pendulina (alpine rose), Rosa rugosa (beach rose), Rosa spinosissima (Scotch rose), many rhododendron including: Rhododendron fortunei (Fortune's rhododendron), Rhododendron minus (Piedmont rhododendron), Rhododendron smirnowii (Smirnow rhododendron) and Rhododendron cultivars ‘Atrosanguineum’, ‘Bicolor’, ‘Catalode’, ‘Catawbiense Album’, ‘Dexter’s Orchid’, ‘Duke of York’, ‘Fundy’, ‘Henry’s Red’, ‘Janet Blair‘, ‘Katherine Dalton’, ‘Scintillation’, ‘Sir Charles Butler’, and ‘Viola’, many azaleas including Rhododendron atlanticum (coast azalea), Rhododendron calendulaceum (flame azalea), Rhododendron kaempferi (torch azalea), and azalea cultivars ‘Brazil’, and ‘Lady Rosebery’, Sorbus americana (American mountain ash), Spiraea x blanda (bunny spirea), Spiraea chinensis (Chinese spirea), Symplocos paniculata (Asiatic sweetleaf), Viburnum lentago (nannyberry), Viburnum plicatum (Japanese snowball), and Viburnum rafinesqueanum (downy arrowwood). The landscape is lush and green as the grass continues to grow.

Pests/Problems: Winter moth (Operophtera brumata) remains active throughout the landscape. Early instar gypsy moth (Lymantria dispar) caterpillars are active. Azalea sawfly continues to feed. Ilex (holly) leaf roller is active on Ilex verticillata (winterberry). Azalea galls caused by the fungus Exobasidium vaccinia are becoming visible. The previous year’s drought stress has increased Botryosphaeria Dieback on Rhododendron. The effects of drought are also evident on many plants throughout the landscape as they continue to leaf out. Many upper limbs are slow to leaf out or have put out epicormic growth.

Many invasive weeds are thriving throughout the landscape. Alliaria petiolata (garlic mustard) continues to flower and produce seed. Iris pseudacorus (yellow flag) is beginning to flower. Convolvulus arvensis (field bindweed), Cynanchum louiseae (black swallowwort), and Fallopia japonica (Japanese knotweed) continue to increase in size. Untreated Ficaria verna (pilewort) is beginning to go dormant leaving bare spots in the turf. Plantago lanceolata (narrowleaf plantain) is flowering.

Metro West (Acton)

General Conditions: Typical spring-like temperatures continued into this reporting period. It was cool, hot, windy or wet on any given day. The highest temperature recorded for this week was 94° on the 18th which helped immensely with this week’s GDD gain and the lowest temperature recorded was 40° on the 21st. We dodged a heat wave with temperatures recorded in the 90’s on just two days in a row, the 17th and 18th, and not three days when the high was a mere 88°. The average monthly rainfall for May is 4.04” and as of the 23rd I have recorded 3.43” and that number should increase since there is rain in the forecast for later this week. 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), Ilex aquifolium (English Holly), Kerria japonica (Japanese Kerria), Lonicera maackii (Amur Honeysuckle), Laburnum x waterii (Goldenchain Tree), Leucothoe axillaris (Coast Leucothoe), Prunus serotina (Black Cherry), Rhododendron spp. (Azalea and Rhododendron), Sorbus aucuparia (European Mountain Ash), Spiraea spp. (Bridal Wreath), Syringa spp. (mid-late blooming Lilac), Vaccinium angustifolium (Lowbush Blueberry), V. corymbosum (Highbush Blueberry), Viburnum plicatum var. tomentosum (Doublefile Viburnum), and V. sargentii (Sargent Viburnum). Woody vines in bloom are: Lonicera sempirvirens (Trumpet Honeysuckle), Clematis montana var. ruebens (Anemone Clematis), 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), Allium spp. (Ornamental Flowering Onion), Amsonia hubrichtii (Arkansas Blue Star), Aquilegia spp. (Columbine), Arisaema triphyllum (Jack-in-the-Pulpit), Aurinia saxatilis (Basket of Gold), Bergenia cordifolia (Pigsqueak), Camassia scilloides (Wild Hyacinth), Cerastium tomentosum (Snow in Summer), Chrysogonum virginianum (Green and Gold), Claytonia virginica (Virginia Spring Beauty), Convallaria majalis (Lily of the Valley), Dianthus deltoides (Maiden Pink), Dicentra eximia (Fringed Bleeding Heart), D. spectabilis (Old Fashioned Bleeding Heart), D. spectabilis 'Alba' (White Flowering Old Fashioned Bleeding Heart), Dodecatheon meadia (Shooting Star), Gallium odorata (Sweet Woodruff), Geranium maculatum (Wild Geranium), G. macrorrhizum (Bigroot Geranium), G. sanguineum (Cranesbill Geranium), Hyacinthoides hispanica (Wood Hyacinth), Iberis sempervirens (Evergreen Candytuft), Iris germanica (Bearded Iris), Linaria annua (Money Plant), Mertensia virginica (Virginia Bluebells), Muscari sp. (Grape Hyacinth), Myosotis sylvatica (Forget-me-not), Narcissus spp. (Daffodil), Nepeta spp. (Ornamental Catmint), 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), Primula spp. (Primrose), Salvia nemerosa (Salvia), Stylophorum diphyllum (Wood Poppy), Tiarella cordifolia(Foam Flower), Trillium erectum (Red Flowering Trillium), T. grandiflorum (White Flowering Trillium), T. sessile (Toadshade), Tulipa spp. (Tulip), Uvularia sessilifolia (Bellflower), 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 Ostrya (Hophornbeam) and Ulmus (Elm); and Woolly Beech Aphid on the underside of European Beech leaves. Many weeds are in 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 Dead Nettle) 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: The weather swings this week took us from three days of unusual warmth on May 17-19th, to cool wet conditions on May 22nd, with some brisk winds and thunderstorms in between. Soils are still quite moist. Many plants are experiencing prolonged blooming periods this spring. Tulips are just finishing, as are lilacs - though Syringa meyeri and S. laciniata are in full bloom. Also blooming are Enkianthus campanulatus, Aesculus carnea ‘Briotii’, Cotinus (just beginning), Catawbiense Rhododendrons, Little Epaulette Tree (Pterostyrax corymbosa), Trillium grandiflorum and T. erectum, Dicentra spectabilis, Geranium macrorrhizum, G. maculatum, Viola pedata, Arisaema sikokianum, Arisaema triphyllum, and Corydalis lutea.

Pests/Problems: Gypsy moth caterpillars are feeding on oak, Malus, Fothergilla, Hamamelis and many other woody plants. Some folks are reporting a skin reaction/rash from contact with the young caterpillars. Many ticks are being reported. Asiatic Lily Beetles are active on Lilies and Fritillaria. Mosquitoes and black flies are biting. Boxwood psyllid remains active. Woodchucks and chipmunks are nibbling with abandon.

Pioneer Valley Region (Amherst)

General Conditions: We experienced both unseasonably warm and cool weather during this past reporting period in the Pioneer Valley. In the span of five days, high temperatures varied by 38° F, peaking at a high of 95° F on 5/18 and plummeting down to a high of 57° F on 5/22. The three-day stretch of summer-like temperatures from 5/17–5/19 was particularly searing for this time of year and many trees and shrubs with immature leaves were wilting and drooping in the intense afternoon heat. The warm nights helped to accelerate leaf and shoot development for many plants that were slowly flushing new growth. Since then, we’ve entered a period of mild to cool conditions with a mixture of sun, rain and persistent cloud cover. Light to moderate precipitation over the past week has netted another 0.5″ at most weather stations, further padding the monthly total during this wet spring. The long-term forecast is calling for additional rains that should continue the current trend. Overall, full leaf out is behind this year, with many trees and shrubs not yet attaining full leaf size at the time of writing. Turfgrasses are still bright green but growth has slowed a bit over the past week. Soil temperatures have crossed the 60° F threshold in full sun settings and new root development is well underway for most trees and shrubs. Winds were strong during the hot spell late last week but have since become very calm.

Pests/Problems: Numerous landscape red maples appear thin at this time, with sparse and undersized foliage. For most, the thin appearance appears related to the abundance of seed produced this year. Many red maples had a mast year in 2015 and had a similar, unthrifty appearance. Crabapples are continuing to flush new growth, indicative of the abundant soil moisture this year. However, older leaves are showing signs of severe infection from apple scab in the form of pale brown, circular spots that may be coalescing to consume large areas of the leaf surface. Entomosporium leaf spot of hawthorn is becoming visible, but only as very small, yellow-colored spots. The disease does not becoming overtly conspicuous until late in the growing season (mid-August onward) but due to the high precipitation this spring, we can accept high levels of disease on susceptible trees this autumn. Anthracnose of red maple and beech has been observed in forest settings. For maple, dark-colored spots and blotches can be scattered across the leaf surface but are primarily angular in shape. For beech, lesions are mostly clustered along the primary veins, especially at the leaf margins.

Gypsy moth feeding continues and damage is widespread on a variety of hosts on the UMass campus. Numerous caterpillars ballooned onto one-year-old American elm saplings planted in an open field at the Agricultural Learning Center. Egg masses and feeding caterpillars were found at Stanley Park in Westfield, confirming that overwintering took place west of the Connecticut River in 2016. For white pines that have 2015 needles, yellowing and premature shedding is taking place now due to the actions of needle blight pathogens. For trees with only 2016 needles in the canopy, needle tip browning is common and widespread in both forest and landscape settings (see images below). For trees that are robust, needles are elongating from developed candles while for severely stressed white pines, candles are just developing and needles are not yet elongating. Now is a good time to protect newly developing shoots and needles on species of Thuja and Chamaecyparis that have been impacted by needle blight pathogens (Phyllosticta and Pestalotiopsis) in previous years. Continue to scout for the spruce spider mite on Picea, Abies, Thuja and Tsuga in particular. The flecking symptoms on the needles may be difficult to observe in full sun but the light webbing produced by the mites can be readily observed at most times. “Syringing” (dislodging the mites with a strong stream of water) can be an effective management strategy when infestations are light to moderate. Sanitation pruning should continue for trees and shrubs. Removing blighted branches and shoots is critical to reduce inoculum in the canopy that can be used to spread existing infections by opportunistic pathogens. Mosquitoes are abundant in shaded settings during the day and everywhere at dusk.

Berkshire Region (Great Barrington)

General Conditions: The weather roller coaster ride continued over the past week. May 17, 18, and 19 had temperatures in the mid to upper 80s with some areas in the south county area reaching into the low 90s on May 18. A cold front moved in on May 20, dropping temperatures to normal or just below. A slight warmup is under way as this report is being prepared. While the hot temperatures prompted an end to Forsythia and magnolias still in bloom early last week, lilacs remain in bloom, giving us one of the most spectacular show of lilac blooms in recent memory. Nights remain cool and setting out of tender transplants, i.e. annual flowers and vegetables, should be delayed until night temperatures are consistently above 50° F. Rainfall was light during this period but soil moisture levels are good and soil is very workable. Turfgrass is growing vigorously.

Pests/Problems: There has been an uptick in number of plant pests, as well as a serious uptick in reports of tick attachments to outdoor workers. This season is shaping up to be one of very high deer tick numbers and outdoor workers should follow all the recommended measures to protect themselves from these potentially disease-bearing ticks.

New pest sightings this reporting period include: pear blister mite on Pyrus sp., spittlebug on herbaceous plants, imported willow leaf beetle on willows (egg, larvae, and adults), forest tent caterpillars, leaf rollers on many tree species including crabapple, gray dogwood (Cornus racemosa), shadblow (Amelanchier canadensis), and sand cherry (Prunus x cisterna), and four-lined plant bug (nymphs). The latter pest commonly feed on herbaceous perennials and herbs. The ones observed this week were on hyssop (Hyssopus officinalis). Many woody ornamentals, annual flowers, and berry crops are also hosts to the four-lined plant bug.

On-going pest problems observed include: boxwood psyllid, boxwood leaf miner (pupal stage), eastern tent caterpillar, spruce spider mite, woolly beech aphid, and viburnum leaf beetle (larvae). Leaf galls are becoming more prominent. Leaf spot diseases could be seen on foliage of many woody plant species. Fire blight on sand cherry, cedar apple rust and apple scab on crabapples, and powdery mildew on ninebark (Physocarpus opulifolius) are expanding. Mosaic virus was found on roses.

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:

Red ring rot of eastern white pine (Pinus strobus) caused by Porodaedalea (photo by T. Simisky). Red ring rot of eastern white pine (Pinus strobus) caused by Porodaedalea (formerly Phellinus pini). Tall pines in a dense watershed forest stand that are believed to be approximately 100-years-old. In 2016, the canopies appeared very thin and subsequent investigation has determined needle blight, the eastern white pine bast scale and branch/trunk cankering from Caliciopsis pinea are all present. Swollen knots were observed on the trunk with small, perennial fruiting bodies emerging. One tree was felled and cut into sections to expose significant trunk rot at the base of the tree, extending to approximately 20′ above the soil line. Porodaedalea is commonly found on pine and spruce but can be cryptic as the fungus usually does not produce a fruiting body until advanced decay has established.

Cercospora leaf spot of rhododendron (Rhododendron ′Honey Dew′) caused by Pseudocercospora handelii. Plant is 10-years-old and has been present at the site for five years. This spring, numerous brown-colored spots, scattered across the leaf surface, were observed. Many have coalesced to create large, necrotic blotches. The shrub resides in a shaded setting with overhead irrigation, creating ideal conditions for a foliar blight pathogen such as Pseudocercospora. Switching to drip irrigation should help to reduce disease severity in the future.

Blue spruce (Picea pungens) decline due to needle blight (Stigmina lautii), infestation of the elongate hemlock scale (Fiorinia externa) and stem cankering from Phomopsis and Botryosphaeria. The tree is approximately 25- to 30-years-old and exhibits the increasingly common symptoms of severe decline for landscape blue spruce. Needles have prematurely shed on all lower canopy branches to a height of about 20′. While uncommon, spruce can serve as a host for the elongate hemlock scale in landscape settings.

Needle blight of Green Giant arborvitae (Thuja standishii × plicata 'Green Giant') caused by Phyllosticta and Pestalotiopsis. Numerous trees, roughly five-years-old, were planted in a tight row to provide screening from the adjacent roadway. Based on submitted photos, the trees appear to be planted too close together and have very little room to grow outward. This spring, needle browning and outright death was observed, affecting many. Drip irrigation provided supplemental water last season and the trees receive a mixture of sun and shade.

Transplant shock, drought stress and secondary needle blight caused by Phyllosticta on spruce (Picea sp.). An approximately 15-year-old spruce was transplanted into a residential landscape two years ago and was not mulched or provided with supplemental water. Based on submitted photos, the root flare is not visible at the soil line. In May of this year, a significant volume of needles in the lower canopy began browning and prematurely shedding.

Needle tip browning and premature shedding of 2016 needles as the 2017 shoots and needles elongate on an eastern white pine at UMass. Eastern white pine on the UMass campus in severe decline. The needle blight pathogen Septorioides strobi was found to be very abundant on blighted needle tips.

 

 

 

 

 

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:

  • A lady beetle (ladybug) larva seen on Rosa rugosa on 5/24/17 in Amherst. The larvae and adults of many ladybugs (Coccinellidae) can be voracious predators of pest insects such as aphids, thrips, and mites. (Simisky, 2017) A Beneficial Sighting: the larvae of many Coccinellidae (ladybird beetles, ladybugs) are great predators of pest insects such as aphids, mites, and thrips. Although some species (such as the multicolored Asian lady beetle, Harmonia axyridis) may overwinter in homes in large, obnoxious numbers, the adults and larvae of many lady beetle species can be quite voracious predators and help us to manage some pest insects.

 

 

 

 

  • Assorted sizes of gypsy moth as observed on 5/24/17 on an oak in Amherst. Note that the characteristically blue and red “warts” or spots are beginning to develop in the older instars. (Simisky, 2017) Gypsy moth seen feeding on Rosa rugosa on 5/24/17 in Amherst. (Simisky, 2017) Feeding damage from gypsy moth caterpillars on oak seen on 5/24/17 in Amherst. (Simisky, 2017) Gypsy Moth: Lymantria dispar caterpillar dispersal via ballooning may be at an end, in most locations. (See previous Landscape Messages and the “Insects” section for more information regarding prior 2017 observations.) To be sure, monitor local gypsy moth caterpillars and look for tattered host plant foliage with young, still small gypsy moth caterpillars feeding beneath. If you find a host plant leaf with tattered holes in it, flip the leaf over and you may find a small, roughly ¼- ½-inch long gypsy moth caterpillar feeding on the leaf underside. These caterpillars are dark in color and hairy. Based on observations at a single location in Amherst, caterpillars are mostly still in the 2nd instar stage (at that location), but some 3rd instar individuals were seen with more defined, raised “wart-like” spots on the dorsal side of the insect. In Amherst, the “warts” of some of the gypsy moth caterpillars are developing to include the characteristic blue 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. 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. Over the past few weeks, gypsy moth caterpillars have unfortunately been observed on the UMass Amherst campus, despite an apparent lack of readily visible egg masses. Research suggests that young gypsy moth caterpillars can balloon into an area from at least a mile away. For more information about gypsy moth egg hatch, please visit: https://ag.umass.edu/landscape/news/gypsy-moth-egg-hatch-has-begun-in-massachusetts.

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 are less susceptible to Btk. 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 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 need the more “normal” rainfall amounts (non-drought conditions) that we have been experiencing to continue through the rest of May and June, to help facilitate the successful infection of younger gypsy moth caterpillars with the insect-killing fungus Entomophaga maimaiga. However, at this time, it is too early to know what impact this fungus will have on the 2017 gypsy moth population. It is also 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. 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 normal rainfall amounts this season. Only time will tell. So far, according to reports from the Northeast Regional Climate Center, last month (April) showed most (not all) of Massachusetts at or above normal precipitation amounts for that month. As a region, they report from the U.S. Drought Monitor that the Northeast became free of severe drought for the first time since late June 2016 (reported on 4/27/17). See: http://www.nrcc.cornell.edu/regional/drought/drought.html.

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 reported earlier in the season that when sampling for winter moth in host plant buds, at most of their research sites they were observing greatly reduced winter moth numbers this year. Dr. Elkinton reports that in past similar surveys, it was not uncommon to find 20+ winter moth caterpillars per host plant bud sampled. Earlier in the 2017 season, at most of their research sites, the Elkinton lab reports finding roughly 1-2 caterpillars every other bud or so that was sampled. Please see the Regional Reports above for local information regarding this insect. As of Friday, 5/26/17, the Elkinton Lab reported that winter moth caterpillars (at the sites they are monitoring) are mostly in the 3rd instar at that time, with a few 4th instar larvae present. As of Thursday, 5/25/17, the Elkinton Lab reports that more 4th and 5th instar winter moth larvae have been found at the majority of the sites they are monitoring, but that caterpillar development is variable across the landscape.

For individuals managing winter moth in ornamental plants, spinosad is effective through ingestion and contact on winter moth (including older caterpillars) once ornamental plant leaves have fully expanded, however it should not be applied to plants in flower as it is toxic to pollinators until it has dried (which can take 1-3 hours depending upon local environmental conditions). For more in-depth information regarding winter moth management, see the Identification and Management Fact Sheet above.

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: 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 conducting their heaviest feeding on plant roots at this time. Pupation will occur by the end of this month. 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, by the end of May 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.
  • Eastern Tent Caterpillar: Malacosoma americanum (ETC) tents continue to grow in size and 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. If the tents and the growing caterpillars within are found early enough, this is a great way of removing these insects without the use of chemicals. 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. 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 this month and throughout the growing season and the overlap of many developmental stages at any given time can be observed.
  • European Pine Sawfly: Neodiprion sertifer caterpillars or sawflies are active. Reports of this insect on Mugo pine were made on 4/27/17 in Framingham. At that time, the tiny, newly hatched sawflies were still located on the very needles from which they emerged. For other locations, see the Regional Reports above. The 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. Larger numbers can be treated with an insecticidal soap spray when the caterpillars are still small. Spinosad products can be used whenever the caterpillars are actively feeding, usually by mid-May and when caterpillars are still small. Bacillus thuringiensis Kurstaki is not effective against sawflies. 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 and were observed on 5/17/17 to be approximately 1 inch in length in Amherst. 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 late May or 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.
  • Lily leaf beetle adults continue to mate, lay eggs, and feed. See how many beetles you can count in this photo taken on 5/24/17 in Amherst. (Simisky, 2017) Two mating pairs of lily leaf beetle adults seen on 5/24/17 in Amherst. Each female is capable of laying 250-450 eggs. (Simisky, 2017) Lily leaf beetle larvae were spotted on 5/24/17 in Amherst. Larvae of this species coat themselves in their own frass (excrement) as a defense mechanism. Keep that in mind if hand-picking them for removal. (Simisky, 2017) Lily Leaf Beetle: Lilioceris lilii adult beetles were observed causing feeding damage, mating, and eggs were laid on plants in Amherst. As of 5/24/17, frass or excrement-covered larvae of this insect were found feeding in Amherst. For the most part, adults are easily visible and still mating and laying more eggs. 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/

  • 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.
  • Tiny nymphs of the two-marked tree hopper continue to feed on wafer ash seen in Amherst on 5/24/17. Typically, these insects 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

Plant of the week: Syringa meyeri ‘Palibin’

Syringa meyeri ‘Palibin’ Syringa meyeri ‘Palibin’ Syringa meyeri ‘Palibin’ Syringa meyeri ‘Palibin’ is a compact, densely branched lilac growing 4-5’ tall with an equal or wider spread. The pale pink, fragrant flowers are in smaller panicles than the common lilac, but are abundant, covering the plant. Flowers occur in May, and emerge after the common lilac. Leaves are small (less than 2”) and ovate. Palibin Korean lilac is best sited in full sun for best flowering but will tolerate part shade. Plants can be used as a specimen, as a foundation plant, in the shrub border or in groups. They should be planted where the fragrance can be appreciated. Foliage is resistant to powdery mildew, but plants will still benefit from good air circulation. Prune after flowering. Syringa meyeri ‘Palibin’ is drought tolerant once established and attracts hummingbirds and butterflies. This plant is a great choice for someone that wants an old-fashioned common lilac but doesn’t have the space.

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