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Landscape Message: June 23, 2017

June 23, 2017
Issue: 
14

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 30. 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 June 21. 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

555

75

67

0.50

555

12:00 PM 6/21

Southeast

544

77

67

1.27

544

5:00 PM 6/21

North Shore

627

68

63

2.13

627

9:30 AM 6/21

East

719.5

74

70

1.96

719.5

5:00 PM 6/21

Metro West

672

66

62

1.14

672

5:50 AM 6/21

Central

691

65

66

1.12

691

8:30 AM 6/21

Pioneer Valley

697

74

68

1.13

697

9:00 AM 6/21

Berkshires

574

65

61

1.23

574

8:30 AM 6/21

AVERAGE

635

71

66

1.31

635

-

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 macrophylla (Bigleaf Hydrangea) Begin * * * * * * *
Hydrangea arborescens (Smooth Hydrangea) Begin Begin * * * * Begin *
Itea virginica (Virginia Sweetspire) Begin Full Begin * * * Begin Begin
Rhus typhina (Staghorn Sumac) Begin Full Begin Begin/Full Begin Begin Begin/Full Begin
Sambucus canadensis (American Elderberry) Begin Begin/Full Begin/Full Begin/Full Begin/Full Full Full Full
Ligustrum spp. (Privet) Begin/Full Full Begin/Full Begin/Full Begin/Full Full Full Begin/Full
Catalpa speciosa (Northern Catalpa) Begin/Full Full Full Full Full Full Full Begin/Full
Syringa reticulata (Japanese Tree Lilac) Begin/Full Full/End Full Full/End Full Full Full Begin/Full
Cladrastis lutea (Yellowwood) End End End End End End End End
Philadelphus spp.(Mockorange) Full/End Full/End Full/End End Full/End End End Full/End
Hydrangea anomala petiolaris (Climbing Hydrangea) Full Full Full * Full/End Full Full/End Full
Kalmia latifolia (Mountain-laurel) Full Full Full Full Full/End Full/End Full/End Full
Cotinus coggygria (Common Smokebush) Full/End End Full/End Full/End End End End End
Cornus sericea (Red Osier Dogwood) End * End * End * End End
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

Cape Cod Region (Barnstable)

General Conditions: The average temperature from June 14 - June 21 was 65.5° F with a high of 77° F on June 21 and a low of 47° F on June 15. There were several reports from different towns on the Cape with below 40° F temperatures on June 15. Barnstable recorded 0.50 inches of rain from June 14 - June 21. Most of the precipitation occurred over a several day period from June 16-18 with additional isolated storms on June 19 & 20. The period was dominated by light rain, mist, fog and clouds from June 16-20 with 100% relative humidity for most of those 5 days. Some areas of the Cape received up to 1.5 inches of precipitation during the time frame. Topsoil moisture is short to adequate depending exact precipitation amounts. Subsoil moisture remains adequate to slightly excessive where high water tables or clay soils exist.

Pests/Problems: Gypsy moth caterpillars continue to feed. Defoliation from gypsy moth is extensive in parts of the upper and lower cape. In some areas gypsy moth are causing defoliation on pitch pine. Weather conditions have been ideal for infection by the entomopathogenic fungi, Entomophaga maimaiga, and signs of infection are showing up in many locations. Other active insects observed over the past week include elongate hemlock scale on hemlock, bristly nose roseslug sawfly on rose, chilli thrips on hydrangea, andromeda lacebug on Japanese andromeda, black turpentine beetle on pitch pine and earwigs on just about everything. Black oak that had been damaged by cynipid gall wasp in the past are showing symptoms of infection by Diplodia corticola, bleeding cankers from the trunk. Phytophthora has been diagnosed on poorly performing privet hedges in areas with poor drainage. Azalea gall is very active on susceptible azalea and rhododendron. Weeds are doing wonderfully with the plentiful moisture. Weeds in bloom include; black medic (Medicago lupulina), multiflora rose (Rosa multiflora), black swallow-wort (Cynanchum louiseae), white campion (Silene alba), white clover (Trifolium repens), purple clover (Trifolium pratense), rabbitfoot clover (Trifolium arvense), sulfur cinquefoil (Potentilla recta) hawkweed (Hieracium pratense), red sorrel (Rumex acetosella), curly dock (Rumex crispus), goutweed (Aegopodium podagraria), and yellow woodsorrel (Oxalis stricta). Rabbits are abundant.

Southeast Region (Hanson)

General Conditions: Pleasant summer weather continues with temperatures in the low 70’s and low 80’s. Hanson received 1.27 inches of rain and it was appreciated. Soil moisture levels are adequate but will dry out in sunny areas; continue to remind clients to water newly planted or transplanted plants and those plants defoliated by caterpillars.

The following plants are in bloom: Northern Catalpa, Stewartia rostrata, Sinocalycanthus chinensis, Aesculus x carnea, Liriodendron tulipifera (Tuliptree), Cornus kousa, Magnolia virginiana (Sweetbay magnolia), Styrax japonicus, Hypericum androsaemum ‘Mrs. Gladis Brabazon’,Weston hybrid azaleas, Hydrangea anomala petiolaris, Itea virginica, Spiraea sp., Kalmia, Calycanthus floridus (Common Sweetshrub), Indigofera sp., landscape roses, Rosa rugosa, Clematis sp. including the lovely Clematis ‘Betty Corning’, Lonicera sempervirens, Lonicera ‘John Clayton’, ‘Stella D’Oro’ and otherearly daylilies, Alchemilla mollis, Salvia sp., Geranium sp., Anenome canadensis, Persicaria polymorpha, Lamium, Allium, Nepeta sp., Dianthus sp., Tradescantia, Lupines, Corydalis lutea, Valeriana officinalis, and Foxgloves.

Stewartia pseudocamellia (Japanese Stewartia), Lysimachia ciliata, Astilbe and Hydrangea quercifolia are beginning bloom.

Many of the last of the spring bloomers are ending bloom, but what a great spring it was: Doublefile viburnum, Amsonia sp., Thalictrum aquilegifolium, Baptisia australis, Aquilegia (Columbine) and Doronicum are ending bloom. Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) continue to display their colorful “smoke” (plume-like hairs that form on the sterile flowers). Rhus typhina (Staghorn sumac), a native plant, is in full bloom with its’ small greenish flowers. Some may say that the flowers are not much to look at ornamentally, but they attract a great number of pollinators, including honey bees.

For the third year in a row in many areas, the overwintering stems of most Hydrangea macrophylla were winter-killed and or bud-killed, leaving brown dead ‘sticks’ where vibrant green stems, foliage and flower buds should be. The more cold hardyhybrids like Hydrangea macrophylla ‘Blue Billow’ or H. ‘Lady-in-red’ are producing flower buds, and the remontant, or repeat-blooming, Hydrangea macrophylla, which produce flowers on new wood, should provide the landscape with color.

Hanson is at 1,330 GDD - Growing Degree days, Base 40.

Pests/Problems: A few Gypsy moth caterpillars are at 4th instar but most are quite large at 5th & 6th instar (only the females go to a 6th instar. According to UMass Entomologist, Dr. Joe Elkinton, gypsy moth caterpillar pupation has started in some areas of MA but not in Plymouth County. However, he said that pupation should start soon and expects that gypsy moth caterpillars will finish within a week. Right now, many of these large late instar caterpillars remain feeding on oaks etc. and foliage is disappearing quickly. However, there is some good news: many of these large, late instar caterpillars are dying from disease (both virus and fungus in the Hanson, MA area) and can be seen hanging head-down, or head and tail down (like an upside down V) on the trunks of trees. Damage is spotty with complete defoliation of some trees and partial damage to others. At the Hanson site, several large oak trees are completely stripped of foliage. The two apple trees are also completely defoliated; damage remains heavy on small white pine, Betula dahuvica, (Dahurian birch or Asian black birch), Fothergilla and other understory plants. Overall, considering the enormous number of gypsy moth eggs produced last June 2016, it is incredible that we are not seeing total devastating damage to more trees this year in this area. Again, according to Dr. Elkinton, this is due in part to the wet spring and the presence of disease which effectively removed many of the caterpillars. We still have a week or so to go but right now, landscapes look pretty good, considering what could have been; hopefully this will continue to the case through next week. For detailed Gypsy Moth information, see the Insect Section of the Landscape Message.

Monitor dogwoods for dogwood sawfly larvae which should soon be active on certain dogwood species like Cornus controversa, Cornus racemosa and Cornus sericea. Deer flies are active. Just an FYI: In the United States, deer flies along with the dog tick, wood tick and the lone star tick are capable of transmitting a bacterium, Francisella tularensis, which causes tularemia. https://www.cdc.gov/tularemia/index.html Deer tick nymphs remain active. Continue to take precautions and conduct deer tick checks frequently.

The following insects remain active: birch leaf miner; European chafer beetles; Asiatic garden beetles, lacebugs on Japanese Andromeda (Pieris japonica), Rhododendron and azaleas; roseslug sawfly; White pine sawyer beetle (Asian longhorned beetle look-alike); Hemlock woolly adelgid; elongate hemlock scale; cottony camellia scale on Meserve hollies and Taxus; Fletcher scale on Taxus; Taxus mealy bug, earwigs; planthoppers; leafhoppers; stink bugs; mosquitoes; aphids; four-lined plant bugs; lily leaf beetle; slugs; snails; wasps; azalea whitefly; flies, dog ticks and deer tick nymphs. Mosquitoes remain abundant and annoying. Remind clients to empty containers of standing water or to treat with Bacillus thuringiensis israelensis (Bti).

Beneficial insects remain active. This is not only a good year for butterflies but in Hanson, MA, a Great Crested Flycatcher was observed along with a Scarlet Tanager!

Wilting foliage and stems, attributed to stem cankers, were seen in Indigofera amblyantha and Cercis canadensis.Continue to remove Azalea leaf galls (Exobasidium vaccinii) from deciduous azaleas and place them in the trash. The following plant diseases continue to be observed: foliar leaf spots on dogwood; sycamore anthracnose; maple anthracnose; dogwood anthracnose; blackspot on roses; apple scab on crabapples and apples;Phyllosticta hamamelidis (Witchhazel blight) on ‘Arnold Promise’ witchhazel; Monilinia (brown rot) on Kwanzan cherry; botrytis blight on peonies.

The following weeds are in full bloom: Numerous grasses, hawkweed, Japanese honeysuckle (Lonicera japonica - Massachusetts invasive plant), oxeye daisy, and red and white clover. Multiflora rose is ending bloom.

North Shore (Beverly)

General Conditions: We experienced fluctuating temperatures this reporting period. The first half of this period day temperatures were in the low to mid 70s and night temperatures were in the low 60s. In the second half of the period day temperatures climbed into the high 80s and 90s and night temperatures were in the low 70s. June 18 and 19 recorded temperatures above 95 degrees Fahrenheit with high relative humidity. We gained 121 growing degree days at Long Hill during this period. A powerful storm passed through on June 16 bringing with it heavy rains. 2.0 inches of rainfall were recorded after the storm passed through. A total of 2.13 inches of rainfall were recorded at Long Hill during this period.

Woody plants seen in bloom include: Tulip tree (Liriodendron tulipifera), Japanese tree lilac (Syringa reticulata), Peking tree lilac (Syringa pekinensis), Stewartia (Stewartia rostrata), Bigleaf Magnolia (Magnolia macrophylla), Privet (Ligustrum spp.), Kousa Dogwood (Cornus Kousa), Lemoine Deutzia (Deutzia lemoinei), Sweet azalea (Rhododendron arborescens), Virginia sweetspire (Itea virginica), Magician Deutzia (Deutzia magicien), Oakleaf Hydrangea (Hydrangea quercifolia) and Mountain Laurel (Kalmia latifolia). Herbaceous plants in bloom include: Peonies (Paeonia sp.), Virginia rose (Rosa virginiana), Baptisia (Baptisia australis), Foxglove (Digitalis purpurea), Spiderwort (Tradescantia spp.), Leopard’s bane (Doronicum spp.), meadowsweet (Filipendula ulmaria), Catmint (Nepeta sp.), Geranium (Pelargonium spp.), Rodger's flower (Rodgersia aesculifolia), Aruncus (Aruncus dioicus), Corydalis (Corydalis lutea), Allium (Allium sp.), Ox-eye daisy (Leucanthemum vulgare) and various of annual flowers.

Pests/Problems: Leaf necrosis probably caused by phyllosticta leaf blotch was observed on Witchhazel (Hamamelis intermedia). Leaf tip necrosis was observed on a Japanese stewartia, probably caused by anthracnose. If you notice these in your landscape, consider sending a sample to the UMass Extension Plant Diagnostic Lab for correct diagnosis of the problem. Poison ivy is growing vigorously in the landscape. Learn how to identify poison ivy to prevent exposure. Multiflora rose (Rosa multiflora) continues to bloom and is easy to identify. Bishops Goutweed (Aegopodium podagraria), another invasive weed, is also in full bloom. Many weeds in the landscape continue to flourish. Take measures to control weeds before they set seed. Mosquitoes and ticks are still very active. Protect yourself with insect repellent when working outdoors especially at dawn and at dusk.

East Region (Boston)

General Conditions: This last week of spring finally saw seasonable spring temperatures as highs ranged from 71° F to 86° F, averaging 79° F, while lows ranged from 50° F to 70° F, averaging 61°F. A cold front came through on the evening of the 16th into the 17th bringing 1.78 inches of precipitation. Surplus precipitation continues this month as we have received 4.26 inches thus far. We have gained 139.5 GDDs bringing us to 719.5 for the year. We welcomed the summer solstice on June 21st. Plants in bloom include: Alchemilla mollis (lady's mantle), Allium schoenoprasum (chive), Amsonia hubrichtii (Hubricht’s bluestar), Baptisia australis (blue wild indigo), Campanula takesimana (Korean bellflower), Clematis sp. (clematis), Coreopsis sp. (tickseed), Cornus kousa (Kousa dogwood), Diospyros virginiana (common persimmon), Hosta sp. (hosta), Ilex glabra (inkberry), Ilex pedunculosa (longstalk holly), Leucanthemum vulgare (oxeye daisy), Lonicera sempervirens (trumpet honeysuckle), Magnolia virginiana (sweetbay magnolia), Platycodon grandiflorus (balloon flower), Potentilla fruticosa (bush cinquefoil), Physocarpus opulifolius (common ninebark), Rhododendron arborescens (smooth azalea), Rhododendron viscosum (swamp azalea), hybrid rose cultivars Rosa ‘Betty Prior’, ‘Bucbi’ Carefree Beauty, ‘Chuckles’, ‘Heritage’, ‘Julia Child’, ‘Sea Foam’, Trifolium pratense (red clover), and Trifolium repens (white clover). Ostrya virginiana (eastern hophornbeam) fruit is especially ornamental at this time.

Pests/Problems: Recent precipitation and favorable temperatures have contributed to undesirable plant growth. Many landscape weeds are flourishing: Celastrus orbiculatus (Oriental bittersweet), Chelidonium majus (greater celandine), Convolvulus arvensis (field bindweed), Cynanchum louiseae (black swallowwort), Glechoma hederacea (ground ivy), and Solanum dulcamara (deadly nightshade). Other weeds in bloom include: Aegopodium podagraria (bishop’s weed), Lotus corniculatus (birdsfoot trefoil), Prunella vulgaris (common selfheal), Rosa multiflora (multiflora rose), and Vicia cracca (bird vetch).

Metro West (Acton)

General Conditions: We welcome the summer season with this week’s report with a gain of 139.5 GDD during this recording period and with a total of 1.14” of rain. The historical monthly average rainfall for June is 3.93” and 3.38” of rain has been recorded for this month so far and it’s not over yet! Woody plants seen in bloom this past week are Catalpa speciosa (Northern Catalpa), Cornus kousa (Kousa Dogwood), C. sericea (Red Osier Dogwood), Ilex glabra (Inkberry), I. pendunculosa (Longstalk Holly), Kalmia latifolia (Mountain Laurel), Ligustrum spp. (Privet), Liriodendron tulipifera (Tulip Tree), Philadelphus spp. (Sweet Mock Orange), Physocarpus opulifolius (Common Ninebark), P. opulifolius 'Summer Wine' (Summer Wine Ninebark), Potentilla fruiticosa (Potentilla), Rosa rugosa (Rugosa Rose), R. 'Knockout' (The Knockout family of Roses), Rosa spp. (Rose), Rhus typhina (Staghorn Sumac), Sambucus canadensis (American Elderberry), Spirea japonica 'Alpina' (Daphne Spirea), Syringa reticulata (Japanese Tree Lilac), Tilia cordata (Littleleaf Linden), and Weigela florida (Old Fashioned Weigela). Woody vines in bloom are: Clematis spp. (Clematis), Hydrangea anomala petiolaris (Climbing Hydrangea), and Lonicera sempirvirens (Trumpet Honeysuckle). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Achillea millefolium (Yarrow), Alchemilla mollis (Lady's Mantle), Allium schoenoprasum (Chives), Amsonia hubrichtii (Arkansas Blue Star), Aquilegia spp. (Columbine), Aruncus aethusifolius (Dwarf Goat's Beard), A. dioicus (Goat's Beard), Baptisia australis (False Blue Indigo), Campanula takesimana ‘Elizabeth’ (Bell Flower), C. spp. (Bell Flower), Centaurea montana (Cornflower), Chrysogonum virginianum (Green and Gold), Clematis recta 'Purpurea' (Clematis), Coreopsis spp. (Tickseed), Dianthus deltoides (Maiden Pink), Dicentra eximia (Fringed Bleeding Heart), Dictamnus albus (Gas Plant), Digitalis purpurea (Foxglove), Filipendula sp. (Meadow Sweet), Gaillardia aristata (Indian Blanket Flower), Geranium sanguineum (Cranesbill Geranium), Hemerocallis 'Stella D'Oro' (Daylily), Hemerocallis spp. (Daylily), Heuchera spp. (Coral Bells), Hosta spp. (Plantain Lily), Iris sibirica (Siberian Iris), Leucanthemum sp. (Shasta Daisy), Lilium spp. (Lily), Lychnis coronaria (Rose Campion), Oenothera macrocarpa (Ozark Sundrops), Nepeta spp. (Ornamental Catmint), Paeonia spp. (Peony), Penstemon digitalis 'Husker Red' (Beardtongue), Perovskia atriplicifolia (Russian Sage), Salvia nemerosa (Salvia), Silene latifolia (White Campion), Thermopsis caroliniana (Southern Lupine), Thymus praecox (Thyme), Tradescantia sp. (Spiderwort), and Veronica umbrosa 'Georgia Blue' (Speedwell).

Pests/Problems: Observed in the landscape this past week were the following: damage to foliage from caterpillars feeding on Acer (Maple), Corylus (Filbert), Fagus (Beech), Malus (crabapple), Ostrya (Hophornbeam), Prunus (Cherry), Quercus (Oak), and Ulmus (Elm); gypsy moth caterpillars feeding heavily on Malus (crabapple); evidence of anthracnose on Platanus (Sycamore); leaf spot on Tilia (Linden). Rosa multiflora, an aggressive vine continues to bloom and is easy to detect with its white flowers and is seen growing in and amongst other trees and shrubs.

Central Region (Boylston)

General Conditions: After a brief period of excessive heat in the previous reporting period the weather settled back to more normal temperatures. Soil moisture is adequate after 1.12” of rain during the reporting week. Among the plants in bloom this week are Cornus kousa, Kalmia latifolia, Styrax japonicus, Aruncus dioicus, Geranium psilostemon, Nepeta ‘Joanna Reed’, Persicaria polymorpha, Iris ensata cultivars, Hydrangea anomala subsp. petiolaris, Knockout Roses, Rosa rugose. Pests/Problems: Gypsy Moth caterpillars continue to feed, leaving pockets of defoliation in their wake. They are also feeding heavily on Betula nigra, Hamamelis cultivars, and Carpinus sp. Rosa multiflora is in full bloom and joins an array of robust and happy weeds which have flourished this spring.

Pioneer Valley Region (Amherst)

General Conditions: For this reporting period in the Pioneer Valley, we saw a return to the wet weather that has characterized the 2017 growing season. The first rain event took place on Friday 6/16 and resulted in modest accumulations (~0.3″). Overcast skies and high humidity then dominated in subsequent days until a large storm system pushed through from the southwest on Monday, 6/19. Dewpoint values prior to the storm peaked to a near-unbearable 75° F at noon on 6/19, pushing the heat index well over 90° F. A strong band of thunderstorms, stretching from the mid-Atlantic to Maine, brought high winds, frequent thunder and lightning and driving rain during the late afternoon and evening hours. Accumulations from the storm ranged from 0.75–1.1″ and provided a thorough watering for turf, annuals/perennials, trees and shrubs. This large storm system brought heavy rains but little relief from the humidity. Temperatures cooled only to the lower 70s and dewpoints remained high during the night but by mid-day on 6/20, dewpoints finally dropped to a comfortable 59°F at Barnes Airport in Westfield. Since then we have experienced near ideal summer weather as we celebrate the summer solstice. Overall, the landscape appears robust and healthy, thanks in large part to the very wet spring that began in early April. Soil temperatures continue their upward trajectory over the past two weeks and the sun readings now hover in the middle 70s.

Pests/Problems: Anthracnose on sycamore, dogwood, beech, oak and maple continues to be a major issue for some landscape trees at this time. Sycamores and plane trees affected by anthracnose will continue to flush new growth but do not appear to have improved much over the past week. Dutch elm disease is starting to appear on American elms in the landscape, in the form of upper canopy flagging (yellowing of leaves on outermost branches). If you manage properties with dying American elm(s), strongly advise your clients to cut them down and remove the material from the site! Dying elms attract elm bark beetles and become major disease reservoirs that can imperil healthy elms in the surrounding area. The spruce spider mite (SSM) also continues to cause major headaches for those managing properties with spruce (especially large Norway spruce), hemlock, true fir, arborvitae, among other landscape conifers. The extended dry weather in 2016 helped to facilitate a large buildup of this destructive pest. The recent heat wave has now exposed much of the damage, which frequently does not appear until the heat of the summer. Scouting for the webbing produced on infested needles has been confounded by the abundance (biblical proportions) of cottonwood seed that has blanketed the valley. This cool season pest feeds in April and May but symptoms do not appear for several weeks. Hence, there is little in the way of management right now for symptomatic trees. Horticultural oils and insecticidal soaps can be effective against spider mites, but may cause a burn to tender foliage, so exercise caution at this time. Regular “syringing”, blasting mites out of the canopy with the strong stream of water, is an effective management strategy when performed regularly early and late in the season. Yet, for large Norway spruce trees with heavy infestations, registered miticides may be the only hope for recovery. Broad-spectrum insecticides should be avoided as there are many natural predators of spider mites, which are not true insects. Thin canopies and undersized foliage on red maples is due to the heavy seed production this year. Arborvitae needle blight and leafminer damage is widespread and visible at this time. Prune and discard these blighted needles as soon as possible, to reduce inoculum in the canopy and tissues that can be colonized by opportunistic fungi. Azalea, rhododendron and Andromeda lacebug damage is high so treatment with registered insecticides may be necessary to avoid further damage from these pests. Lacebugs are actively feeding now on the current season’s foliage and the flecking symptoms are readily apparent. Mosquito populations are overwhelming right now so continue to eliminate standing pools of water on properties where egg laying can potentially take place. Weeds continue to be a nuisance in the landscape with the abundance of rain. If chemical management is utilized for weed control, such as glyphosate, know that the risk of injury from drift is high if the product is used improperly.

Berkshire Region (Great Barrington)

General Conditions: Despite a brief heavy downpour and some strong wind gusts which brought down a few decaying trees and many branches on Monday, June 19, the area was spared from what was predicted to be a much more potent storm. A little less than an inch of rain was recorded for that event. Otherwise it has been a beautiful week for the most part. The natural landscape is lush and verdant as it nears its peak of development. One dominant plant in this rural landscape is the invasive multiflora rose (Rosa multiflora) which can be seen along hedge and fence rows and roads. In the managed landscape, the plant which stands out most is Kousa dogwood (Cornus kousa), with its showy white petal-like bracts. This dogwood has no serious insect or disease problems and is a good alternative to our native flowering dogwood (Cornus florida). The shrub which garners the most attention now, besides various roses, is the long-blooming shrubby cinquefoil (Potentilla fruticosa).Rainfall for the year to date remains about ½ inch above normal but 5 ½ inches above last year. Lawns have benefitted from the rain and remain lush and green.

Pests/Problems: It seems that pest and disease pressure remains low. Diseases reported or observed this past week include: leaf spots (Phyllosticta) on mountain laurel (Kalmia latifolia), black spot on roses, rose mosaic virus (noticeable by presence of yellow squiggly lines, swirls, or tile-like markings on the leaves), powdery mildew on ninebark (Physocarpus opulifolius), apple scab and cedar-apple rust on crabapples. Upon examination, with magnifying lens, of the yellow spots (lesions) on crabapples leaves infected with cedar-apple rust, tiny black dots or pimple-like structures can be seen. These structures produce a sticky exudate containing the male sex cells. Insects attracted to the sticky stuff will carry it to other rust spots, resulting in fertilization of the fungus.

Some pre-mature browning of last season’s needles on white pine was observed on a specimen at the Berkshire Botanical Garden. This same tree showed these symptoms last year. A fact sheet on such pre-mature browning can be found at: https://ag.umass.edu/sites/ag.umass.edu/files/content-files/alerts-messages/2016_white_pine_update.pdf.

Weir’s spruce cushion rust, caused by the fungus Chrysomyxa weirii, was found to have spread from last season’s needles onto the current season’s needles.

Insect problems observed included; oak lace bug on burr oak, imported willow leaf beetle (adults and larvae), elderberry borer (Desmocerus palliatus) on Black Lace elderberry (Sambucus nigra). Other ongoing pest issues are: deer ticks, dog ticks, mosquitoes, slugs and snails, spittlebugs, boxwood leaf miner adults (numbers much fewer), four-lined plantbug, earwigs, sowbugs and pillbugs.

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:

Dutch elm disease (DED), caused by Ophiostoma novo-ulmi, on American elm (Ulmus americana). Lage (49” dbh) landscape elm with a broad, vase-like canopy on the UMass campus. Upper canopy flagging was observed in early June and immediately pruned out to confirm the presence of the pathogen. A therapeutic injection with Alamo (propiconazole) was then performed along with a sanitation prune of any symptomatic branches. This tree suffered from construction injury when the old University apartments were demolished and a parking lot was established nearby. The grade surrounding the tree was significantly altered, likely resulting in compaction/crushing and/or burying of the roots.

Hornbeam anthracnose, caused by Apiosporopsis carpinea, on Eastern hophornbeam (Ostrya virginiana). Tree is approximately 15-years-old and has been present at the site for roughly 10 years. Scattered branch dieback was observed this spring and symptoms were not present in previous years. Closer examination revealed a marginal blight of the foliage, which is typical of foliar anthracnose infections. The tree is watered as needed during extended dry periods and regularly fertilized. Given it’s otherwise good health, the disease should not result in lasting damage.

Canopy dieback of swamp white oak (Quercus bicolor) due to anthracnose, stem cankering and a gall wasp infestation. Tree is 12-years-old and has been present at the site for only two years. Symptoms were apparent in previous years but managing arborist is new to the site. Several trees were planted at the edge of a new parking lot and drainage appears poor; standing water and saturated soils were observed. Two anthracnose fungi were detected (Apiognomonia errabunda and Colletotrichum gloeosporioides s.l.). Stem cankering was the result of Botryosphaeria, a common pathogen on stressed oaks in the region. The gall wasp in question was most likely the oak petiole gall wasp (Andricus quercuspetiolicola). While it was the most conspicuous of the biotic stresses revealed, it is likely the least worrisome, given the level of injury from anthracnose and stem cankering. Lawn irrigation provides additional moisture to the site.

Excessive needle drop and dieback of Norway spruce (Picea abies) due to the following insect pests and fungal diseases: (i) spruce spider mite (Oligonychus ununguis); (ii) eastern spruce gall adelgid (Adelges abietis); (iii) spruce bud scale (Physokermes piceae); (iv) stigmina needle cast (Stigmina lautii); and (v) stem cankering from Setomelanomma holmii. Several trees, seven years of age, planted at the site four years ago. One tree has died and others are showing symptoms (needle yellowing/browning and premature shedding). Trees were established in an open field and do not receive supplemental water at this time.

Decline and dieback of eastern hemlock (Tsuga canadensis) due to suspected drought stress, excessive shearing, elongate hemlock scale (Fiorinia externa) and shoot tip cankering by Phomopsis. Large hedge of eastern hemlock, approximately 25-years-old, aggressively sheared annually to create a dense privacy screen. Scattered, but significant, sections of the hedge are dying or dead. Older needles are fully formed and appear healthy and where new growth is taking place, needles are full-sized. The annual shearing has not only removed the most productive tissues responsible for providing photosynthate for growth and maintenance, but it has created thousands of wounds. Phomopsis was able to readily exploit these points of entrance to establish. Drought stress from 2015 and 2016 is also a likely contributor along with the scale infestation, although the latter was not severe on the submitted sample.

Maple anthracnose, caused by Aureobasidium apocryptum, on Autumn Blaze maple (Acer x freemanii 'Autumn Blaze').

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 crabapple in Amherst viewed on 6/18/17 loaded with gypsy moth and forest tent caterpillars. Eastern tent caterpillars were present in the tree also, but have pupated. (Simisky, 2017) Gypsy moths continue to feed in Amherst on 6/18/17. (Simisky, 2017) A completely defoliated tree in Amherst observed on 6/18/17. Gypsy moth is very active in the immediate area. (Simisky, 2017) Defoliation from gypsy moth at a location in Amherst as viewed on 6/18/17. (Simisky, 2017) Gypsy Moth: Lymantria dispar caterpillars are in various sizes or developmental stages (instars) depending upon the location in Massachusetts. However, observations indicate that in many locations, these larvae are mostly in the 5th instar stage, with some 6th instars present; however some pupating individuals have been spotted in Amherst and Hopkinton. (Reports of pupation come from the Elkinton Lab at UMass.) Male gypsy moth caterpillars go through 5 instars and female gypsy moth caterpillars have 6 instars. Therefore, those seen pupating at this time are most likely males. Male caterpillars will pupate just prior to the female caterpillars; pupation, like the transformation between the previous stages, does not happen all at once for all individuals. Caterpillars that have not yet begun this process will continue to feed, until when most pupate by the end of June. Adult moths emerge in the beginning of July. With pupation, this season’s gypsy moth caused defoliation will cease.

At this time and until the end of June, the defoliation they cause will be most noticeable due to the fact that larger caterpillars can simply eat more. Reports made on 6/6/17 indicate that tree canopy thinning and complete defoliation in certain locations was observed along I-90, approximately 4 miles east of Palmer, MA. On 6/15/17, a “55-65 MPH Survey” (driving along the MA Pike, I-90, on the way to a previously scheduled training) was conducted from the Westfield Exit (#3) to Exit 14 toward 95 south. Gypsy moth defoliation was highly visible beginning in Wilbraham while headed east through Palmer. On either side of the MA Pike, partial or complete defoliation (mostly oaks) could be seen. At mile marker 66.5 (just before) when headed downhill in the eastbound direction over the Quaboag River, there is a certain vantage point where you are at a higher elevation than the surrounding hillsides on either side of the highway. From that point of view, the defoliation was incredible. Large swaths on either side of the surrounding hills were covered in bare trees. When continuing east down I-90, the defoliation on either side of the highway continues through Sturbridge and roughly to the Charlton Plaza. From that point on, the defoliation was significantly less, at least on the trees visible from the highway. This trend continued roughly through Worcester, with any defoliation remaining in patches and certainly not to the extent of what was seen west of there. It seemed to not pick up again until roughly mile marker 98 and then was sporadic and relatively light (again, when thinking about the previously described areas) until you reach Hopkinton and Exit 11A to 495. Defoliation in that area seemed again analogous to what was seen from Wilbraham to the Charlton plaza. By mile marker 108.7, defoliation dropped to sporadic, light patches again. This limited, quick survey ended at Exit 14 and no samples of caterpillars were taken at that time due to safety concerns and time limits. However, it will be interesting to see what the 2017 aerial survey maps from the MA Department of Conservation and Recreation look like for defoliation this year. Reports from the Elkinton Lab were made on 6/21/17 that again confirmed the extent of the defoliation seen from Palmer to Sturbridge along the MA Pike. Dr. Elkinton also reported seeing pupation beginning in Hopkinton and Amherst at that time, as mentioned above. Finally, the Elkinton lab also reports defoliation along the Holyoke Range as of 6/21/17, in areas where defoliation of this extent was not seen last year.

Reports of the sound of frass (excrement) dropping from the canopy where these caterpillars are feeding continue. (The sound of frass dropping could be heard in Belchertown on 6/9/17 and Hanson on 6/15/17. Reports of this activity were made again for Belchertown and Wilbraham on 6/21/17.) Caterpillars will be reaching 2+ inches in length and have been reported to be mostly in the 5th instar in Amherst as of 6/21/17. These caterpillars are dark in color, hairy, and the “warts” have developed to include the characteristic blue and red coloration, along with a head capsule that is yellow and mottled with black markings. In the 5th instar, the head capsule becomes very wide when compared to the width of the rest of the caterpillar, giving them a comical, almost bobble head-like appearance. In areas where gypsy moth caterpillars are abundant, citizens are dealing with caterpillars crawling all over the sides of homes, sheds, lawn furniture, and dropping from these locations and nearby trees. Caterpillars may be found on driveways and decks, along with shredded sections of leaves due to their feeding, which are easily visible against that background. In Amherst on 6/12/17, caterpillars were found in a cluster, hidden behind a sign that was leaned up against a Norway maple. The sign was moved from the shaded area beneath the tree to a location in full sun, in order to inspect the cluster of caterpillars on the tree. In moments, the sun heated the sign and 50+ caterpillars came crawling down from where they were hidden along the edges of said sign. On 6/21/17, reports came from Wilbraham about the massive amount of frass building up on lawn furniture, including tables. See the Regional Reports above for more information about gypsy moth activity.

According to prior reports from the Elkinton Lab, successful infection of gypsy moth caterpillars with the insect-killing fungus Entomophaga maimaiga, has begun, and continues. Dr. Joseph Elkinton and his lab group, along with other local cooperators, and Dr. Ann Hajek and her lab group from Cornell University, are conducting a study that he is referring to as the “Cloud of Death Experiment”! What Dr. Elkinton means by this is that the research will aim to 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 (or virus) is responsible. The Elkinton Lab has sites in Amherst, Belchertown, Brewster, Eastham, Hanson, and West Bridgewater to conduct these observations. To date, they have reported fungal activity at some of these sites, now with approximately 30% mortality due to Entomophaga maimaiga observed in caterpillars being reared on artificial diets (in the lab) collected from these sites. Anecdotally in the field, however, some reports of gypsy moth caterpillars “disappearing in large numbers” have been made at various locations across the state. This may be, in part, due to the behavior change that occurs when caterpillars reach the 4th instar. If an observer is used to seeing the caterpillars actively feeding on foliage during the day, they may be surprised to find them missing. The 4th instar caterpillars will change their behavior such that they feed at night, while hiding during the day. That being said, in high populations, even 4th instar caterpillars will feed at any time, daytime included.

Reports of caterpillar dieback at a location in Marlborough were also made on 6/15/17. The Elkinton Lab expects the percentage of caterpillars killed by the fungus will increase; but unfortunately, the number of fungal-killed caterpillars in central and western MA (eastern portions of Franklin, Hampshire, and Hampden counties) are not as high as we would like them to be. The Elkinton Lab reports that areas on the Cape and South Shore, such as Plymouth, are experiencing much more caterpillar mortality due to the fungus than areas in the central and western part of the state. He suspects that unless the story changes before July, there may be plenty of gypsy moths to pupate in central and western MA and therefore plenty of adults to mate and females to lay overwintering eggs for 2018 in those locations. Look to the Landscape Message for continued updates about Dr. Elkinton’s research as well as reports concerning the activity of Entomophaga maimaiga in Massachusetts.

Fungal spores were isolated from a caterpillar collected from Belchertown on 6/9/17; however, the majority of the (many) caterpillars observed on that date were healthy and actively feeding (even during the day) at that location. Gooey, droopy, brown liquid-filled gypsy moth caterpillar cadavers were collected from a site in Hanson, MA on 6/15/17. These were viewed beneath a phase-contrast microscope and were confirmed to be filled with the occlusion bodies (protein-coated virions, or infective form, of a virus) of the NPV virus that kills gypsy moth. It was confirmed that these sampled caterpillars from that particular site died from the virus; although, the Elkinton Lab also reports activity from Entomophaga maimaiga at that site as well. There are certainly high densities of gypsy moth at that location, so it makes sense that the NPV virus would be successfully transmitted between densely populated caterpillars.

To treat individual, landscape ornamental and shade trees, 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. Treatment will become unnecessary once pupation really picks up in the population over the next week or so. Pupae and adults of the gypsy moth do not feed (defoliate trees) and therefore no management is necessary.

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. Gypsy moth damage has also been reported on blueberry crops in Massachusetts this year.

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.

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.

  • 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. Adults 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.
  • 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. This was observed again on 6/8/17 and 6/14/17. 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.
  • An old eastern tent caterpillar tent in a crabapple also defoliated by gypsy moth and forest tent caterpillars in Amherst observed on 6/18/17. (Simisky, 2017) Eastern tent caterpillars have pupated in Amherst. Observed 6/18/17. (Simisky, 2017) Eastern Tent Caterpillar: Malacosoma americanum (ETC) impacts cherry, crabapple, apple, ash, birch, willow, maple, oak, poplar, and witch-hazel. Pupation of this insect had occurred at a site visited in Amherst on 6/18/2017. Management of this insect is no longer applicable for the remainder of this season, as pupae and adults do not feed.
  • Elongate Hemlock Scale: Fiorinia externa is found on eastern, Carolina, and Japanese hemlock, as well as yew, spruce, and fir. Crawlers will be present throughout the growing season and the overlap of many developmental stages at any given time can be observed.
  • Emerald Ash Borer (EAB): 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) and most recently, cultivated olive (Olea europaea). (See: https://academic.oup.com/jee/article-lookup/doi/10.1093/jee/tox139.) Adult insects of this species are emerging at this time, as we have surpassed in most areas of the state 450-550 GDD’s (see Environmental Data above). Signs of an EAB infested tree may include D-shaped exit holes in the bark, “blonding” or lighter coloration of the ash bark from woodpecker feeding (chipping away of the bark as they search for larvae beneath), and serpentine galleries visible through splits in/upon peeling the bark, from larval feeding beneath. Positive identification of an EAB-infested tree may not be possible with these signs individually on their own.

For a map of the known locations of emerald ash borer in the state, as well as further information about this insect, please visit: https://ag.umass.edu/fact-sheets/emerald-ash-borer. If you believe you have located EAB-infested ash trees, particularly in an area of Massachusetts not identified on the map provided, please report it at the Massachusetts Introduced Pests Outreach Project: http://massnrc.org/pests/pestreports.htm.

  • European Elm Scale: Gossyparia spuria is a type of felt scale and was observed on an elm on 6/7/17 and 6/14/17 in Amherst. First noted in New York in 1884, this non-native scale is now widespread in North America and is found on native and European elms, but also rarely on hackberry and Zelkova. This insect can cause yellowing of foliage, premature leaf drop, and eventually dieback on its host. Honeydew and thus sooty mold are produced. The females observed in Amherst have produced a ring of white fibers around their black, oval bodies. By the end of June, these females will lay eggs that hatch into bright yellow crawlers, which will disperse to the midrib and leaf veins on the underside of elm leaves where they will remain to feed. Crawlers are tiny and magnification is necessary to observe. Natural enemies such as parasitic wasps and predatory insects have been reported as successful in managing this insect.
  • Fletcher Scale: Parthenolecanium fletcheri (soft scale) was observed on taxus (yew) in Amherst on 6/8/17 and 6/14/17. Several effective parasites will impact these scale populations and any management decisions should seek to preserve them. Dead, desiccated female scales appear at this time as covers (test) that one might expect from an armored scale and should not be confused for one. When removed, it is easy to find hundreds of tiny, white colored eggs beneath the female (you will need a hand lens to observe). This scale is commonly found on yew and arborvitae (but has also been reported on juniper and hemlock). It may be confused with the European fruit lecanium (P. corni), which has a much broader host range. Depending upon the host plant, crawlers of the fletcher scale will hatch by the end of June and management may be targeted between 1029-1388 GDD’s, base 50°F. Large populations of this scale may lead to host plant yellowing, premature needle drop, and production of honeydew giving way for sooty mold. Each female produces on average 500-600 eggs. The degree of impact this insect may have depends on the host. Some hosts, such as yew, are reportedly more heavily impacted by this scale as when compared to arborvitae, where visible damage may be seldom. Horticultural oil, insecticidal soap, or neem oil may be used according to label instructions in order to preserve natural enemies.
  • 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 insects can defoliate their host plants, but are not currently in large populations in all areas in the state. At a location in Amherst, FTC’s were observed to have perished due to a fungus (different species of Entomophaga affect these native caterpillars than the one found in gypsy moth). At a location in Belchertown on 6/9/2017, many large FTC’s were observed feeding alongside gypsy moth caterpillars. Pupation of forest tent caterpillars will begin soon, but they were still observed to be feeding in Amherst on 6/18/17.
  • 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 hatched in 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: Lilioceris lilii adult beetles were still causing feeding damage, mating, and eggs were laid on plants in Amherst on 6/14/17. More frass or excrement-covered larvae of this insect were also found feeding in Amherst at this time. These larvae are growing ever-larger and are completely devouring leaves; whereas their smaller counterparts are still skeletonizing. 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. (Although when many plants are involved, mechanical management may not be practical.)

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: These small, caterpillar-like sawfly 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. One species, Allantus cinctus, may require management again in mid-August; otherwise the window for management will pass typically by mid-June.
  • Sumac flea beetle feeding on Cotinus spp. in Ithaca, NY on 6/20/17. (Simisky, 2017) Sumac flea beetle larvae feeding on Cotinus spp. in Ithaca, NY on 6/20/17. (Simisky, 2017) Sumac flea beetle feeding on Cotinus spp. Larger larvae completely consume the leaf. (Simisky, 2017) Sumac flea beetle feeding on Cotinus spp. The larvae of this Chrysomelid beetle cover themselves with a protective shield of frass (excrement) like lily leaf beetles do. (Simisky, 2017) Sumac Flea Beetle: Blepharida rhois larvae were observed feeding on a Cotinus spp. (smoketree/smokebush) on 6/20/17 while on a visit to Ithaca, NY. After photos were sent to Dan Gilrein, Entomologist with Cornell Cooperative Extension, Jason Dombroskie, Coordinator with the Cornell Insect Diagnostic Lab, and Rick Hoebeke, Entomologist and Collection Manager of the Collection of Arthropods at the University of Georgia, it was agreed upon that the sumac flea beetle was responsible for feeding upon this host. Sumac and smoketree/smokebush belong to the family Anacardiaceae, so it is not surprising to find this insect feeding on something related to Rhus glabra, for example. Jason Dombroskie confirmed that this insect was very active in the area three years ago, so this did not come as a surprise. These Chrysomelid or flea beetle larvae were seen feeding on the undersides of the foliage, both skeletonizing (the smaller larvae) and completely defoliating (the larger larvae). Larvae are purple with black heads and 3 pairs of thoracic legs. Like lily leaf beetles, they retain large amounts of fecal matter (frass) on their backs in the form of a shield to deter predators. Feeding by these beetles can be patchy between plants.
  • Taxus Mealybug: Dysmicoccus wistariae was spotted on taxus in Amherst on 5/31/17, 6/8/17, and 6/14/17. 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: 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. (This was observed for the first time in Amherst on 6/14/17, although the nymphs have been active for quite some time now this season.) Still small 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 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 this season. At this time, larvae have dropped to the soil to pupate and adult beetles will soon be present in most locations where they exist in late-June through roughly October, or when the first frost hits. Adult beetles will create their own feeding damage, but will also mate and females will lay eggs in the stems of the viburnums, typically beginning in late-June to mid-July until October. This beetle feeds exclusively on many different species of viburnum including but not limited to susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum, and V. rafinesquianum. 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 previously reported from Middlesex, Plymouth, and Worcester counties in MA. (One was also observed in Jaffrey, NH while hiking in Monadnock State Park on Saturday, June 3.) Adults will continue to be active through July. 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 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 until July.

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.

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

Hydrangea quercifolia, oakleaf hydrangea Hydrangea quercifolia, oakleaf hydrangea Hydrangea quercifolia, oakleaf hydrangea Hydrangea quercifolia, oakleaf hydrangea Plant of the Week: Hydrangea quercifolia, oakleaf hydrangea

Native to the southeastern United States, Hydrangea quercifolia is a multi-stemmed, mounded shrub reaching 4-8’ tall (although plants can reach 12’). The common name, oakleaf hydrangea, comes from the oak-like leaf shape. Leaves are 3-8” long, 3-7 lobed, and have serrated margins. The coarse foliage is dark green above with a tomentose white to tan underside. Fall color is an attractive blend of red, red-purple, and sometimes orange with leaves holding late into fall. Flowers are upright, pyramidal clusters of white flowers. Similar to other Hydrangea species, panicles contain small fertile flowers along with showy sterile flowers near the base of the clusters. Peak bloom is Early July with and flowers turn pink as the age in late summer. Old stems have exfoliating bark with prominent lenticels that provides winter interest. Plants are best grown in a well-drained, moist soil in full sun to part shade. Mulching helps to retain moisture. When needed, oakleaf hydrangea should be pruned immediately after flowering, although pruning is not often needed. Hydrangea quercifolia can suffer from twig kill and flower bud injury in zone 5, so plants should be protected in winter. Bark, flower buds, and leaves are poisonous. Hydrangea quercifolia can be used in groups, shrub borders, or as a specimen.

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

Landscape Turf

Insects

Japanese beetle adults on the wing

According to this week's UMass Extension Vegetable Team newsletter, Japanese beetle adults have been spotted on some crops in Worcester County in Massachusetts. This is a little earlier than I would have expected, but the very warm weather we experienced 10 days ago no doubt sped the process. So many of you can expect to start seeing Japanese beetles and oriental beetles flying soon. Normally it takes about 7 to 10 days from the time a beetle emerges until she is able to lay eggs, so the timing for application of neonicotinoids (imidacloprid, chlothianidin, or thiamethoxam) to target white grubs will be close to "normal" this year. The labels call for applications "when the beetles are laying eggs", which should be from early July through early August for most off you in southern New England.

Soil moisture is certainly much higher than last year at this time, so I would expect beetles to start laying eggs right on time, and not delay like they did last year.

Armyworms???

Just a reminder to all that there have been reports of armyworm activity in parts of New York. The potential is there for some turf areas in New England to be affected if adults are deposited during storms. See the May 31, 2017 Management Update for photos of armyworm caterpillars - the base color is a very dark blue or black, with two light brown stripes along each side of the body.

Annual bluegrass weevils (ABW)

Most of the golf courses in southern New England are approaching the end of the first generation. As you know, we have been monitoring six sites in New England for the Syngenta Weevil Trak Program. We are seeing some interesting trends this year.

Two sites have been particularly interesting to track. One site in Bloomfield CT is about 200 degree days "ahead" of our site in Albany NY. Both sites have had large numbers of larvae in the areas they have left untreated for us. Very unexpectedly, the weevil development in Albany is about a week ahead of the Connecticut site, even though the Albany site is cooler. We are not at all sure why, although the soil temperature in Albany might be a litter warmer. The situation provides further proof that the weevil is a resilient #$&# !

The ABW population appears to be less synchronized in this first generation than usual - at all of our sites. Most years we notice that most of the insects are about the same size so in a given week, they might be 25% second instars, 25% third instars, 25% fourth instars, and 25% fifth instars. (Note to the reader - I HATE "Spell Check", as it is changing "instar" to "install" every time I type it!!!)

This year several of our sites have had every stage present in a sample, from tiny larvae through large larvae and pupae. One sample this week had some second instars and some pupae in the same sample!!!

The take home message for now - Many of our locations in southern New England have reached the point where most of the insects are prepupae (which look like larvae but are done feeding) and pupae. This means the worst of the damage should be over for now. Once the insects reach the pre pupa or pupa stage, there is no benefit to applying an insecticide.

Start monitoring for adult activity about a week from now. Adults often can be seen moving on the surface, particularly on putting greens and collars, on warm, sunny days.

If you came through the spring with little visible damage, you may want to wait and see what kind of adult activity you see in early July. Remember that the population appears to be less synchronized this year. The good news is that the distribution of insect stages will likely be more spread out the rest of the year, which means you are not likely to have a period where a large percentage of the individuals are large larvae. So damage in that case is likely to be less severe, but more prolonged.

The bad news is that the lack of synchronization will make it much more difficult to get good "control" with any insecticide application. If you are targeting adults, a lot of the individuals will not be in the adult stage. If you are targeting small larvae, many of the critters will be in other stages and will not be susceptible.

So as always, be vigilant - and good luck!

Report by Dr. Pat Vittum, Professor Emeritus and Extension Turf Entomologist, UMass Amherst Stockbridge School of Agriculture.


Additional Resources

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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