Source: http://ag.umass.edu/landscape/landscape-message-jun-1-2018
Timestamp: 2019-04-20 16:31:32+00:00

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The following data was collected on or about May 30, 2018. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2018 calendar year. This information is intended for use as a guide for monitoring the developmental stages of pests in your location and planning management strategies accordingly.
General Conditions: The average temperature over the period was 62°F with a high of 86°F on May 26 and a low of 50°F on May 27. Approximately a quarter of an inch of precipitation fell during the period with most occurring on May 27. Clouds, mist and high humidity occurred for about 72 hours starting on the 27th, resulting in ideal conditions for foliar diseases. Topsoil and subsoil moisture conditions still remain adequate; however, disturbed soils (tilled) and new plantings will require supplemental watering.
Pests/Problems: Winter moth caterpillars continue to feed on the foliage of susceptible hosts; damage to oaks, maples, apples, blueberry and others is starting to become more visible. Gypsy moth can be found on the outer Cape. Other pests or damage observed this week include: viburnum leaf beetle (Pyrhalta viburni), on viburnum, rose slug sawfly on rose, boxwood psyllid (Psylla buxi) on boxwood, boxwood leafminer (Monarthropalpus flavus) adults have emerged on boxwood, hydrangea leaftier on smooth hydrangea, slugs on bearded iris, sycamore anthracnose on sycamore, brown rot on Kwanzan cherry, fungal cankers on rose, leaf and flower gall on azalea and spot anthracnose on dogwood. The following weeds are in bloom: autumn olive (Elaeagnus umbellata), bush honeysuckles (Lonicera spp), garlic mustard (Alliaria petiolata), mouse-ear chickweed (Cerastium vulgatum), yellow rocket (Barbarea vulgaris), henbit (Lamium spp.), Veronica spp., buttercup (Ranunculus spp.), red sorrel (Rumex acetosella), narrowleaf plantain (Plantago lanceolata) and black medic (Medicago lupulina). Rabbits are abundant. Black-legged ticks (deer tick) nymphs are active so keep yourself protected with permethrin treated shoes and clothing.
General Conditions: We experienced more variable and changeable New England spring weather this past week. It was 89 degrees on May 25 and 91 degrees on May 26. Then the temperature dropped to 50 degrees on May 27 and 51 degrees on May 28. With those earlier warm days and just a trace of rain, soils are drying out, but plants look good; it is a colorful spring. Hanson received only 0.30 inches of rain and could use more. Remind clients to water their plants, especially those newly planted or that were defoliated or damaged by last year’s caterpillar feeding.
The following plants are in full bloom: Aesculus x carnea (red horsechestnut), Cornus kousa, Cornus controversa, Cornus alternifolia, Laburnum watereri (goldenchain tree), Prunus serotina (black cherry), late blooming magnolias, Aesculus hippocastanum (horse chestnut), Rutgers hybrid dogwoods (Stellar series), numerous Rhododendrons, Robinia hispida, Kerria, Lonicera ‘John Clayton’, Aristolochia durior (Dutchman's pipe), numerous viburnums (including Viburnum opulus, V. plicatum var. tomentosum (doublefile viburnum), V. sargentii), beautybush, Abelia mosanensis, Chionanthus virginicus, Cytisus scoparius (Scotch broom), late lilacs like Syringa meyeri, Syringa x prestoniae ‘James Macfarlane’ and Syringa ‘Miss Kim’, Clematis, Calycanthus floridus (Carolina allspice), Weigela florida, Wisteria floribunda (Japanese wisteria), Allium, Baptisia australis and Baptisia hybrids, Tradescantia , Anemone canadensis, Amsonia spp., Thalictrum aquilegifolium, Geranium spp., Buglossoides purpurocaerulea, Doronicum spp., Tiarella cordifolia (foam flower), Lamiastrum galeobdolon, Lamium, Dicentra spectabilis (bleeding heart), Saruma henryi, Cypripedium spp.,(lady’s slipper), Polygonum bistorta ‘Superbum’, Corydalis lutea, Siberian Iris, bearded iris, Phlox subulata, Phlox divaricata, Phlox stolonifera, Hyacinthoides hispanica, Trillium spp., Galium odoratum (sweet woodruff), Polygonatum spp. (Solomon's seal), Stylophorum diphyllum (wood poppy), Arisaema dracontium, Arisaema ringens, (Jack-in-the-pulpit), Ajuga, bearded Iris, Mertensia virginica (Virginia bluebells), Aquilegia spp. (columbine), Vinca minor, Doronicum spp., and Dicentra spectabilis. The following plants are ending bloom: Enkianthus campanulatus and Convallaria majalis (lily-of-the-valley).
Oak pollen was flying around fast and furiously this past week and many were complaining of allergies - next up, white pine pollen. It appears to be a banner year for all kinds of tree seeds to be germinating: maples (Norway, sugar, red), Kousa dogwood, etc. See the Weed Section of the Landscape Message for management suggestions. Continue to remove seedlings of Massachusetts invasive plants like Norway maple, barberry, autumn olive and burning bush before they become established. Also prune and/or shear barberry, autumn olive and burning bush to remove flowers and newly set seeds to prevent further seed dispersal. White pines continue to look stressed with many brown needles as well as those with branches or whole trees that are declining or dead. For more up to date information, please see the Disease Section of the Landscape Message.
Pests/Problems: Winter moth caterpillars have started pupation and will soon be ending their feeding for this season. This is difficult to observe, as there have been so few winter moth caterpillars to monitor this season. Without the feeding damage from winter moth caterpillars, it has been wonderful to see birch, maples, oaks, flowering crabs, etc. with an abundance of intact foliage.
Gypsy moth caterpillars remain small in some areas, as 2nd and 3rd instars, and are larger in other areas, showing 3rd and 4th instar stages. Damage to plants, especially oaks, is beginning to show, with more gypsy moth caterpillars being seen on oaks at this time. Continue to monitor deciduous plant material: birch, roses, oaks, beech, maples, Fothergilla, crabapples, blueberry, etc. and manage if needed. See the Insect Section of the Landscape Message.
Viburnum leaf beetle larvae are active (photo below). This is a relatively new (2004) alien insect pest in Massachusetts. The photo was taken in Kingston, MA. Viburnum leaf beetle attacks only Viburnum plants. Both the adult beetle and the larval stage are destructive to Viburnums. The most susceptible viburnums are: Viburnum dentatum; V. opulus; V. nudum; V. rafinesquianum; V. propinquum and many others are known to be susceptible.
See the Insect Section of this Landscape Message.
Monitor Iris sibirica (Siberian iris), Iris pseudacorus and bearded Iris. Look for tattered flowers (photo 2 below); this is the damage caused by a small white maggot (photo 3) of the Orthacheta Bud Fly, sometimes referred to as the Iris bud fly. The maggots feed on the pollen in flower buds and the emerging flowers appear tattered. The maggots also feed down into the base of the flower, then into the stem. Once done, they drop down to pupate. Not much can be done to prevent this damage now, but removing and destroying the newly damaged flowers and stems may help to manage it for next year.
The following insects are also active: carpenter ants, imported willow leaf beetle, boxwood psyllid, spruce spider mite, hemlock woolly adelgid, elongate hemlock (Fiorina scale) scale, Eastern tent caterpillar, aphids, woolly beech aphid on beech, slugs, snails, ants, deer flies, wasps, hornets, carpenter bees and dog ticks. A silver-colored sawfly, Monostegia abdominalis (photo 4), was observed feeding on Lysimachia ciliata ‘Purpurea’. In past years, this sawfly has been observed in high number, feeding on a variety of Lysimachia. Lily leaf beetle and larvae are active on true lilies. Monitor the undersides of the foliage and look for the dark-colored, slimy, feces-covered larvae. Hand-pick and destroy the adults, larvae and eggs when possible, or manage with a labeled insecticide. Monitor the tips of Euonymus branches. Look for leaf tips webbed together, a sign of Euonymus caterpillars (cream colored with black spots) which web the leaf tips together and feed. Roseslug sawfly remains active on roses and untreated foliage looks like “burned” or tan lace. Azalea sawfly appears finished feeding for the season. Deer tick nymphs remain active and will be active for a few months. The deer tick nymph stage is often thought to be the stage most responsible for transmitting Lyme disease. Repellents and frequent tick checks are recommended for everyone working or playing outdoors, especially in grassy areas or areas with leaf litter. See the Insect section of the Landscape Message. Mosquitoes are numerous this year, even during sunny, windy days! Remind clients to empty containers of water to help prevent breeding and consider using Bti (Bacillus thuringiensis israelensis) in birdbaths, plant saucers, etc. Beneficial insects, like hoverflies, are active. Swallowtail butterflies have been observed.
Foliar diseases have begun to show up, such as apple scab on apples and crabapples, resulting in the ground littered with yellow, blighted leaves. Monilinia (brown rot) is showing up on Kwanzan cherry. The fungal disease, Phyllosticta hamamelidis (witchhazel blight) is showing up on thefoliage of ‘Arnold Promise’ witchhazel. Look for irregular shaped brown splotches.
Lonicera japonica (invasive), buttercups, clover, ground ivy, garlic mustard, hawkweed, veronica and chickweed are in full bloom. Squirrels have been nipping the tips of red maple branches, littering the lawn. They may have been feeding on the developing seeds (samaras) which are numerous this year. Deer, wild turkeys, voles and chipmunks continue to be nuisances and raccoons have arrived on the scene.
General Conditions: The weather during this reporting period was variable with some nice sunny days and some cloudy days. Three days during this period felt like summer days with day temperatures in mid 80s. The other days were seasonable with day temperatures in mid 60s. Night temperatures were mostly in the low to mid 50s during this period. We gained 115 growing degree days at Long Hill during this reporting period for a year-to-date total of 444 growing degree days. Many plants were in bloom during this period and for most plants the flower display has been more spectacular this year. Many azaleas and rhododendrons were in full bloom. Other woody plants seen in full bloom include: common horsechestnut (Aesculus hippocastanum), constellation Rutgers flowering dogwood (Cornus rutgersensis), handkerchief tree (Davidia involucrata var. vilmoriniana), common lilac (Syringa vulgaris), doublefile viburnum (Viburnum plicatum var. tomentosum), slender Deutzia (Deutzia gracilis), Wisteria (Wisteria floribunda), Wright viburnum (Viburnum wrightii), little leaf lilac (Syringa microphylla), sapphireberry (Symplocos paniculata), American cranberrybush viburnum (Viburnum trilobum), Siberian pea tree (Caragana arborescens), white tree Wisteria (Wisteria floribunda), Chinese neillia (Neillia sinensis), sweet shrub (Calycanthus floridus) and tree peony (Paeonia suffruticosa) . 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: Viburnum leaf beetles are enlarging and causing serious damage on susceptible viburnum varieties. There is minimal damage by winter moth larvae observed in the area. 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. Poison ivy is growing vigorously in the woods. Learn to identify poison ivy by young, shiny, reddish leaves of three before you go out into the woods.
General Conditions: We had another week of fluctuating temperatures. A high of 89°F on May 26 was followed by a high of 63°F on May 27 and 62°F on May 28, rebounding to 86°F on May 29. Overall, high temperatures ranged from 62°F to 89°F, averaging 77°F; low temperatures ranged from 50°F to 63°F, averaging 54°F. Precipitation was minimal, accounting for 0.26 inches. Overall, rainfall during May has been below average, with 2.31 inches of recorded precipitation. Supplemental watering may be necessary, especially on newer plantings. We gained 109 GDDs over the last week. The landscape changes daily, some plants are beginning to form fruit as others are just coming into bloom. Herbaceous plants in bloom include: Allium giganteum (giant onion), Allium schoenoprasum (chives), Amsonia hubrichtii (bluestar), Aquilegia canadensis (columbine), Aristolochia macrophylla (Dutchman’s pipe), Carex spp. (sedge), Centaurea montana (perennial cornflower), Clematis spp. (clematis), Geranium macrorrhizum 'Bevan's Variety' (bigroot geranium), Hemerocallis fulva (orange daylily), Iris germanica (bearded iris) cultivars, I. sibirica (Siberian iris), Lupine perennis (wild lupine), Maianthemum canadense (Canada mayflower), M. racemosum (false solomon’s seal), Nepeta spp. (catmint), Ornithogalum umbellatum (garden star-of-Bethlehem), Paeonia suffruticosa (tree peony), Phlox paniculata (garden phlox), Polygonatum biflorum (smooth Solomon's seal) and Ranunculus bulbosus (St. Anthony's turnip).
Woody plants in bloom include: Abelia mosanensis (fragrant abelia), Aesculus pavia (red buckeye), A. turbinata (Japanese horsechestnut), Calycanthus floridus (eastern sweetshrub), Chionanthus retusus (Chinese fringetree), C. virginicus (white fringetree), Cotinus coggygria (European smoketree), C. obovatus (American smoke tree), C. 'Grace' (smokebush), Cotoneaster horizontalis ‘Robustus’ (rockspray), Fraxinus ornus (flowering ash), Kolkwitzia amabilis [Linnaea amabilis] (beautybush), Leucothoe axillaris (coast leucothoe), L. fontanesiana (drooping leucothoe), Liriodendron tulipifera (tulip tree), Lonicera etrusca (Etruscan honeysuckle), L. sempervirens (honeysuckle), Pawlonia tomentosa (princess tree), Philadelphus spp. (mock orange), Physocarpus bracteatus (twinpod ninebark), Potentilla fruticosa (shrubby cinquefoil), Prunus serotina (black cherry), Rhododendron calendulaceum (flame azalea), R. fortunei (Fortune's rhododendron), Rh. (rhododendron) cultivars ‘Duke of York’, ‘Echse I’, ‘Henry’s Red’, ‘Katherine Dalton’, ‘Madame de Bruin’, ‘Mist Maiden’, ‘Mrs. P. D. Williams’, ‘Old Port’ and ‘Souvenir d’Anthony Waterer’, Rh. (azalea) cultivars ‘Lady Rosebery’ and ‘Toucan’, Rosa 'Bucbi' Carefree Beauty (rose), Sophora davidii (Father David's sophora), Spiraea chinensis (Chinese spirea), S. canescens (hoary spirea), S. cantoniensis (Reeve's spirea), Syringa komarowii subsp. reflexa (nodding lilac), S. meyeri 'Palibin' (lilac), S. patula ‘Miss Kim’ (lilac), Viburnum opulus (European cranberrybush), V. plicatum (Japanese snowball), V. plicatum 'Mary Milton' (Mary Milton doublefile viburnum), V. plicatum var. tomentosum (doublefile viburnum), V. rufidulum (rusty blackhaw viburnum), Weigela coraeensis (Japanese weigela), W. hortensis (weigela) and Wisteria floribunda 'Violacea Plena' (double Japanese wisteria). New growth on healthy Tsuga canadensis (eastern hemlock) is visible throughout the landscape. Bracts of Cornus kousa (Kousa dogwood) are very showy at this time. Turtles are very active, moving between ponds and laying eggs.
Pests/Problems: As plants continue to leaf out, deadwood on trees and shrubs is becoming more visible. The cold winter weather was tough on new and young plantings, killing some to the ground and others entirely. Many weeds are in bloom at this time. Woody Euonymus alatus (burning bush) and Frangula alnus (buckthorn) continue to flower. Herbaceous weeds in bloom include: Chelidonium majus (greater celandine), Leucanthemum vulgare (oxeye daisy), Plantago lanceolata (narrowleaf plantain), Ranunculus repens (creeping buttercup), Rumex acetosella (red sorrel), Silene vulgaris (bladder campion) and Tradescantia virginiana (Virginia spiderwort). The first flowers of Cynanchum louiseae (black swallowwort) are beginning to open. Flowers on Alliaria petiolata (garlic mustard) in shaded locations are fading, while those in sunny locations are in seed. Ficaria verna (lesser celandine) is turning yellow, going dormant for the year. Recently germinated weeds include Humulus japonicus (Japanese hops), Phytolacca americana (pokeweed), Portulaca oleracea (purslane) and Polygonum spp. (smartweed). Trifolium pratense (pink clover) and T. repens (white clover) are flowering in turf. Wool Sower Gall (Callirhytis seminator) are visible on oak. Azalea Leaf and Flower Gall (caused by the fungus Exobasidium vaccinii) is beginning to form. Winter moth (Operophtera brumata) continues to feed predominantly on oak species. Viburnum leaf beetles (Pyrrhalta viburni) continue to feed on susceptible plants. Now in their 2nd and 3rd instar, feeding is more apparent.
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 87°F on the 25th and the lowest temperature recorded was 48°F on the 21st. As we approach the end of this month, it appears that this area will not reach the monthly average precipitation for May of 4.04”. As of the 29th, total rainfall recorded for the month was 3.02”. Despite the rain shortage, the landscape is lush! The landscape is green and filled with color and in some stage of bloom at this time are the following woody plants: Aesculus hippocastanum (horsechestnut), Aronia arbutifolia (black chokecherry), Cladrastis lutea (yellowwood), Cornus florida (dogwood), C. x rutgersensis 'Ruth Ellen' (Rutgers hybrid dogwood), Cornus sericea (redosier dogwood), Crataegus spp. (hawthorn), Gymnocladus dioicus (Kentucky coffeetree), Kerria japonica (Japanese Kerria), Leucothoe axillaris (coast Leucothoe), Prunus serotina (black cherry), Rhododendron spp. (Rhododendron and Azalea), Rosa rugosa (rose), Spirea spp. (bridal wreath), Syringa spp. (mid-late blooming lilac), Viburnum plicatum var. tomentosum (doublefile Viburnum), and V. sargentii (Sargent Viburnum). Woody vines in bloom are: Aristolochia macrophylla (Dutchman’s pipe), Clematis spp. (Clematis), Lonicera sempirvirens (trumpet honeysuckle), and Wisteria spp. (Wisteria). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Ajuga reptans (bugleweed), Allium spp. (ornamental flowering onion) including A. schoenoprasum (chives), Aquilegia vulgaris (columbine), A. canadensis (columbine), Amsonia hubrichtii (Arkansas blue star), Chrysogonum virginianum (green and gold), Convallaria majalis (lily of the valley), Dianthus deltoids (maiden pinks), Dicentra eximia (fringed bleeding heart), D. spectabilis (old fashioned bleeding heart), D. spectabilis ‘Alba’ (white flowering old fashioned bleeding heart), Dictamnus albus (gas plant), Gallium odoratum (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), Lamium maculatum (dead nettle), Nepeta spp. (ornamental catmint), Papaver orientale (poppy), Phlox divaricata (Canadian Phlox), P. stolonifera (creeping Phlox), Polemonium reptans (Jacob’s ladder), Polygonatum commutatum (great Solomon seal), P. odoratum 'Variegatum' (variegated Solomon’s seal), Potentilla tridentata (cinquefoil), Primula spp. (primrose), Salvia nemerosa (salvia), Stylophorum diphyllum (wood poppy), Tiarella cordifolia (foam flower), Veronica umbrosa ‘Georgia Blue’ (speedwell), Vinca minor (periwinkle), Viola spp. (violet) and Zizia aptera (heart-leaved Alexander).
Pests/Problems: Observed in the landscape this past week were the following: Winter moth caterpillar feeding on the foliage of Malus (apple, crabapple) and Ulmus (elm) and Gypsy moth caterpillars feeding on the foliage of Corylus (filbert) and Quercus (oak). Many of our most invasive weeds have flowered and are beginning to set seed. Those include: Alliaria petiolata (garlic mustard), Berberis thunbergii (barberry), Elaeagnus umbellata (Autumn-olive), Euonymous alatus (burning bush) and Rhamnus cathartica (common buckthorn). Lonicera maackii (Amur honeysuckle) an invasive, woody shrub continues to bloom. Other weeds seen in bloom are Glechoma hederacea (ground ivy) and Lamium purpureum (purple dead nettle). 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.
Bulbs in bloom: Hyacinthoides hispanica (Spanish bluebells) and ornamental flowering onion (Allium species).
Pests/Problems: Spittlebug, leaf gall (finger gall?) on cherry (Prunus spp.) and elderberry boring beetle. Gypsy moth present and still very active on oaks, witch hazels, crab apples, apples and birches in particular.
General Conditions: Another week of variable spring weather in the Connecticut River Valley. Conditions have been mostly sunny with high temperatures primarily in the 80s and lows in the 50s and 60s. Saturday, 5/26 was downright hot as we continue to acclimate to the increasing height and intensity of the sun. We had another cool and rainy weekend day, this time it was Sunday, 5/27 when temperatures steadily dropped through the morning and afternoon hours into the lower 50s. The contrast between the two days was staggering; at 4:30 PM on 5/26 it was 90° F while at the same time on 5/27 it was 55° F. We’ve gained nearly an hour of daylight over the course of May as we churn towards the summer solstice. Rainfall accumulation was minimal over the past week, averaging less than 0.25” at most weather stations, and overall, below-average precipitation was recorded for the month of May. From 1981 through 2010, Amherst has averaged over 4” of rainfall in May. This year, totals in the valley have ranged from 1.40” (Greenfield), 2.00” (Springfield) and 2.75” (Northampton). Franklin County has fared worse than Hampshire and Hampden Counties, a reversal of what is normally encountered. As a result, the U.S. Drought Monitor shows abnormally dry conditions (D0 category) developing in extreme northern Franklin County along the Vermont border. Healthy trees and shrubs are thriving, with robust growth continuing to develop. For stressed trees and shrubs, canopy dieback is clearly visible at this time. Lawn grasses continue to grow at a strong rate, but in exposed areas with better drained soils, browning has developed as a result of the recent heat. Surface soils are drying in many locations but subsurface moisture remains adequate. In addition to the mating calls of tree frogs, crickets can now be heard during the evening hours, a sure sign of summer.
Pests/Problems: Gypsy moth caterpillars and, to a lesser extent, forest tent caterpillars are continuing to feed on a wide array of forest and landscape trees in eastern portions of the valley. White pine needle shedding continues and the ground beneath some large, declining trees on the UMass campus is covered with brown needles at this time. White pine pollen is also abundant and coating any nearby surface. Apple scab leaf spots and blotches can now be readily observed on apple and crabapple. Premature shedding is already starting for some infected leaves. Typically, these are undersized leaves in deep shade that become yellow prior to casting. Woolly elm aphids can be found on landscape elms. Infested leaves become twisted and curled with thickened, reddish-green leaf tissue. Uncurling the foliage reveals large masses of feeding aphids. Aphids were also observed feeding on rose and honeysuckle flower buds. Last season’s conks produced by Ganoderma sessile (previously G. lucidum) can still be found at the base of infected trees. The conks are dark red to maroon on the surface with a dark brown (and often moldy) pore layer. They are often growing from the main trunk or buttress roots close to the soil line. Blue atlas cedars that were injured during the cold snap in late December through early January are recovering nicely in most settings. Mosquito populations continue to be very high right now. It’s nearly impossible to be out at dusk without swarming hordes descending, even in exposed areas.
General Conditions: Except for Sunday, May 27, it was a very warm and dry week. For the period, the high temperature occurred on May 29 when the thermometer registered 90°F at this monitoring site. Overall, May has been a dry month, especially the past three weeks. Fortunately, soil moisture was quite high going into this month and remained moist through the month with the occasional rain. However, the recent stretch of dry weather has left the soil surface (upper inch) crusted. Beneath the crust the soil is moderately moist. Nevertheless, the crust of bare soils should be broken via cultivation to allow better penetration of rain when it does occur. Overall, the landscape is lush and trees and shrubs are now fully leafed. This would be a good time to assess the general health of woody plants by examining those specimens which are poorly foliated. Lawns on sunny hillsides are struggling a bit due to the lack of rainfall and may need irrigation. Newly seeded and sodded lawns must be monitored for watering needs. Pines have started to release pollen, a very irritating problem for outdoor workers and UMass Landscape Message scouts with pollen related allergies.
Pests/Problems: Black-legged ticks remain a major issue in Berkshire County. A simple walk across a lawn will often result in a tick or two or more latching onto the transgressor. Spraying clothing with a permethrin formulation designed to repel ticks is advisable for those working or otherwise spending time outdoors. Workers should familiarize themselves with all the recommended precautions against tick attachments. Despite the lack of rainfall during the past several weeks, there are enough breeding grounds that mosquito populations are very high. Keep in mind that, as with ticks, mosquitoes are vectors for many serious diseases, e.g. West Nile. Wasps and carpenter bees are abundant. Among the plant pests observed this week are: viburnum leaf beetle (larvae), forest tent and eastern tent caterpillars, boxwood leafminers (pupae and adult flies), boxwood psyliids, woolly beech aphid and imported willow leaf beetle (larvae). Plant diseases found this week were: apple scab, fire blight (on cherry) and black spot on roses.
If you’re interested in learning more about why eastern white pine are declining in the region, follow the links below to select articles from an upcoming special issue on eastern white pine in the journal Forest Ecology and Management. Topics include how climate change and disease, especially needle blight pathogens, are impacting eastern white pine, emerging health issues for white pine and how they’re interacting to produce novel symptoms and the long-term effects of white pine needle damage on growth.
3. Impacts of White Pine Needle Damage on seasonal litterfall dynamics and wood growth of eastern white pine (Pinus strobus) in northern New England.
Herbicide injury on Norway spruce (Picea abies). Trees are approximately 10-years-old and have been present at the site for five years. A granular weed treatment with dicamba was applied to the lawn around the trees, which did not have a mulch ring. Shoots at the base of the trees subsequently grew in a corkscrew pattern, wilted and died. The treatments took place during two consecutive years but have since ceased. The damage is mostly localized and the trees appear to be growing out of the injury. Mulch rings were recently installed around the base.
Phomopsis stem cankering and Rhizosphaera needle cast on a weeping Carolina hemlock (Tsuga caroliniana). Tree is 30-years-old and has been present at the site for 20 years. It resides in full sun without irrigation at the edge of a salt water pool. For the past two years, one area of the canopy has been losing needles and experiencing twig dieback while the rest of the canopy is apparently thriving. Phomopsis is regularly encountered on samples from stressed and declining hemlock. In addition, while Rhizosphaera is not particularly damaging on hemlock, it can be regularly found on this host.
Winter injury and an infestation of the spruce bud scale on dwarf Alberta spruce (Picea glauca 'Conica'). A row of at least seven large trees that were planted in a narrow bed between a house and a driveway with full sun, compacted soils and no irrigation. Upper portions of the canopy experienced some significant dieback as a result of winter injury, which is quite common for this host. Browning and shedding needles and localized stem dieback has left several bare patches in the canopy. The spruce bud scale is a non-native pest that attaches itself to the base of shoots where it extracts fluids. The scale is most often found infesting this host, but can also be found on other spruce species (e.g. Norway spruce).
Needle browning and dieback of creeping juniper (Juniperus sp.) caused by Lophodermium, Phomopsis and Botryosphaeria. Mass of several junipers, approximately 10-years-old growing in full sun with drip irrigation. Within this hillside planting, half of the plants have died, with browning needles and stem dieback.
Gypsy Moth:(Lymantria dispar) host plants include but are certainly not limited to oak (favored), maple, birch, poplar and many others. Gypsy moth caterpillars continue to feed and grow in size. Caterpillars observed on 5/30/18 in Amherst, MA are approximately ½ - ¾ inch in length. Many are in the 3rd instar. 3rd instar caterpillars are starting to develop some color and have noticeable bumps or warts that will eventually become the red and blue spots recognizable in older gypsy moth caterpillars. In other areas of the state, however, development may be further along than what is being seen in Amherst at this time (see Regional Reports above). Reports from Hanson, MA, for example, indicate that some of the gypsy moth caterpillars may have reached the 4th instar: they are approximately 2 inches in length, with developed rows of red and blue warts and yellow color to the head capsule. Historically, gypsy moth caterpillars that have developed the yellow coloration on their head are not as responsive to Btk (Bacillus thuringiensis Kurstaki) applications.
On 5/23/18 in Amherst, MA gypsy moth caterpillars were observed feeding on bur oak, elm, Norway maple, crabapple, fernleaf beech (Fagus sylvatica ‘Asplenifolia’), European linden, Rosa rugosa and apple. Feeding damage from gypsy moth is becoming more apparent, and dark colored and hairy caterpillars can be seen on leaf undersides as well as leaf surfaces. While gypsy moth is still small (under ¾ inch in length, roughly) and actively feeding, and when weather conditions allow, it is a good time to treat caterpillars with Bacillus thuringiensis Kurstaki, or Btk. This active ingredient is derived from natural soil-dwelling bacteria and is specific to Lepidopteran caterpillars. Btk also offers lower risk to the applicator and the environment. (For more information about Btk, visit: http://npic.orst.edu/factsheets/btgen.html .) As caterpillars become larger and more visible (over ¾ inch in length), and create more damage to host plants, they are less susceptible to Btk.
Anyone working in the yard and garden should be aware that there is the potential to encounter deer ticks. The deer tick or blacklegged tick can transmit Lyme disease, human babesiosis, human anaplasmosis and other diseases. Preventative activities, such as daily tick checks, wearing appropriate clothing, and permethrin treatments for clothing (according to label instructions) can aid in reducing the risk that a tick will become attached to your body. If a tick cannot attach and feed, it will not transmit disease. For more information about personal protective measures, visit: http://www.tickencounter.org/prevention/protect_yourself .
Have you just removed an attached tick from yourself or a loved one with a pair of tweezers? If so, consider sending the tick to the UMass Laboratory of Medical Zoology to be tested for disease causing pathogens. To submit a tick to be tested visit: https://www.tickreport.com/ and click on the red “Test A Tick” button. Results are typically available within 3 business days, or less. By the time you make an appointment with your physician following the tick attachment, you may have the results back from TickReport to bring to your physician to aid in a conversation about risk.
Eastern Tent Caterpillar: Malacosoma americanum tents are large and so are the eastern tent caterpillars. Caterpillars are still seen in their tents, but have also been observed wandering on paved and dirt roads in Chesterfield, MA on 5/29/18 and 5/30/18, with many casualties to passing vehicles and hot pavement. This behavior may be due to the fact that they are beginning to seek out sheltered areas where they can spin a cocoon and pupate. Pupation for the species reportedly lasts around three weeks and adult moths historically emerge between late June and early July.
Emerald Ash Borer: (Agrilus planipennis, EAB) This wood-boring beetle readily attacks ash (Fraxinus spp.) including white, green and black ash, has also been found developing in white fringe tree (Chionanthus virginicus) and most recently has been reported in cultivated olive (Olea europaea). Adult emerald ash borers will be emerging from their hosts (ash) soon, roughly between 450 – 550 GDD’s, base 50°F. This is important to note, as anyone using traps and lures to detect the presence of EAB in their community should have their traps hung at this time. 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.
Euonymus Caterpillar: Yponomeuta cagnagella is of European origin and widespread in distribution throughout Europe. It was first reported in North America in Ontario in 1967. As of 5/23/18 and continuing through 5/30/18, euonymus caterpillars are present, feeding and creating an ample amount of webbing at a location in Amherst, MA. The caterpillars are present by the thousands in an understory, forested area. At this location, they have eaten nearly all euonymus leaves in sight. Caterpillars were very active the morning of 5/23/18, feeding in large groups and dangling from host plant branches on webbing.
The euonymus caterpillars (larvae) feed in groups and envelop the foliage of the host plant in webs as they feed. Hosts include: Euonymus europaeus (tree form), E. kiautschovicus, E. alatus and E. japonicus. Mature caterpillars are just under an inch in length, creamy yellow-gray in color with black spots and a black head capsule. By late June these larvae pupate in white, oval-shaped cocoons which are typically oriented together vertically either on host plants or non-hosts in the area. Cocoons can be found in cracks and crevices, or webbed together leaves. The adult moth emerges in late June in most locations. The adult female secretes a gummy substance over her eggs which will harden, making them even more difficult to see. Eggs hatch by mid-August, at which time the tiny larvae prepare to overwinter beneath their eggshell-like covering. These larvae are inactive until the following year when caterpillars group together to feed on newly emerging leaves, creating a mess of webs as they feed. There is one generation per year. Plants may be partially or entirely defoliated and the plants at this location in Amherst are nearly defoliated. Management of young, actively feeding caterpillars with Bacillus thuringiensis is possible if deemed necessary, however many species of Euonymus are considered invasive themselves.
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 at this time. Where populations are low no management is necessary.
Imported Willow Leaf Beetle: Plagiodera versicolora overwintered adults are present and continue to be active and found on willow foliage. Adult beetles will chew holes and notches in the leaves of willow. Egg laying was observed on 5/16/18, 5/23/18 and 5/30/2018 in Chesterfield, MA and will continue through the end of this month. Females lay yellow eggs in clusters on the undersides of leaves. As of 5/30/2018, eggs have hatched at the location in Chesterfield, MA and multitudes of small imported willow leaf beetle larvae are feeding in groups. Larvae are slug-like and bluish-green in color. They feed in clusters and skeletonize the leaves. Most plants can tolerate the feeding from this insect and foliage will appear brown. Repeated yearly feeding can be an issue, in which case management of the young larvae may be necessary. Take care with treatment in areas near water.
Lace Bugs: Stephanitis spp. lace bugs are active and damage is becoming more apparent. Yellow stippling on leaf surfaces, black colored tar-like spots on leaf undersides and lace bug nymphs (immatures) were seen on leaf undersides on 5/30/2018 in Amherst, MA on Rhododendron spp. foliage. Stephanitis spp. lacebugs such as S. pyriodes can cause severe injury to azalea foliage. S. rhododendri can be common on rhododendron and mountain laurel. S. takeyai has been found developing on Japanese andromeda, leucothoe, styrax and willow. Stephanitis spp. lace bug activity should be monitored through September. Before populations become too large, treat with a summer rate horticultural oil spray as needed. Be sure to target the undersides of the foliage in order to get proper coverage of the insects. Fall or early spring soil treatment with imidacloprid has been effective, but be aware of the implications this may have on pollinators attracted to these flowering plants when making management decisions. Certain azalea and andromeda cultivars may be less preferred by lace bugs.
Lily Leaf Beetle: Lilioceris lilii overwintering adults continue to be active in Amherst, MA on 5/30/18. Susceptible hosts include Lilium spp. (Turk’s cap, tiger, Easter, Asiatic and Oriental lilies) and Fritillaria spp. (Note: daylilies are not hosts.) Typically, in May, mating will occur and each female will begin to lay 250-450 eggs in neat rows on the underside of the foliage. In Amherst, MA, orange lily leaf beetle eggs were observed on the underside of host plant foliage on 5/16/2018 and some of these eggs have hatched by 5/23/2018. Frass-covered larvae were observed feeding on 5/23/2018 and 5/30/2018 in Amherst, MA. Larvae are growing ever larger and eating entire leaves. Younger groups of eggs are hatching with still tiny larvae starting to feed by skeletonizing the leaf in groups. Where adults and larvae are seen, they can be removed from host plants with a gloved hand where practical.
This insect is a member of the Order Hemiptera (true bugs, cicadas, hoppers, aphids and others) and the Family Fulgoridae, also known as planthoppers. This insect is a non-native species first detected in the United States in Berks County, Pennsylvania and confirmed on September 22, 2014. Until November 2017, this invasive insect was only known to Pennsylvania. It has now been reported from Delaware (November 20, 2017), New York (November 29, 2017) and most recently in Virginia (January 10, 2018). The Delaware Department of Agriculture announced the finding of a single female spotted lanternfly in New Castle County in the Wilmington, Delaware area. At this time, officials in Delaware note that it is unclear if this individual was an accidental hitchhiker or evidence of an established population in the state. For more information about the find in Delaware, visit: https://news.delaware.gov/2017/11/20/spotted-lanternfly-confirmed-delaware/ . The New York State Department of Agriculture and Markets reported on November 29, 2017 the finding of a single dead individual spotted lanternfly in the state from earlier in the month. A single dead specimen was confirmed at a facility in Delaware County, New York, which is located south-west of Albany. The NYS Dept. of Agriculture and Markets states that this dead individual may have come in on an interstate shipment. For more information about the find in New York, visit: https://www.agriculture.ny.gov/AD/release.asp?ReleaseID=3637 . Most recently, Virginia Cooperative Extension announced the finding of a spotted lanternfly population in Frederick County, Virginia, on January 10, 2018. It was noted that at the location in Virginia, numerous adult lanternflies and egg masses were discovered in addition to more at another site approximately 400 yards away. For more information about the find in Virginia visit: https://ext.vt.edu/agriculture/commercial-horticulture/spotted-lanternfly.html .
The spotted lanternfly is considered native to China, India and Vietnam. It has been introduced as a non-native insect to South Korea and Japan prior to its detection in the United States. In South Korea it is considered invasive and a pest of grapes and peaches. The spotted lanternfly has been reported from over 70 species of plants, including the following: tree of heaven (Ailanthus altissima) (preferred host), apple (Malus spp.), plum, cherry, peach, apricot (Prunus spp.), grape (Vitis spp.), pine (Pinus spp.), pignut hickory (Carya glabra), sassafras (Sassafras albidum), serviceberry (Amelanchier spp.), slippery elm (Ulmus rubra), tulip poplar (Liriodendron tulipifera), white ash (Fraxinus americana), willow (Salix spp.), American beech (Fagus grandifolia), American linden (Tilia americana), American sycamore (Platanus occidentalis), big-toothed aspen (Populus grandidentata), black birch (Betula lenta), black cherry (Prunus serotina), black gum (Nyssa sylvatica), black walnut (Juglans nigra), dogwood (Cornus spp.), Japanese snowbell (Styrax japonicus), maple (Acer spp.), oak (Quercus spp.) and paper birch (Betula papyrifera).
The adults and immatures of this species damage host plants by feeding on sap from stems, leaves and the trunks of trees. In the springtime in Pennsylvania (late April - mid-May) nymphs (immatures) are found on smaller plants and vines and new growth of trees and shrubs. Third and fourth instar nymphs migrate to the tree of heaven and are observed feeding on trunks and branches. Trees may be found with sap weeping from the wounds caused by the insect’s feeding. The sugary secretions (excrement) created by this insect may coat the host plant, later leading to the growth of sooty mold. Insects such as wasps, hornets, bees and ants may also be attracted to the sugary waste created by the lanternflies or sap weeping from open wounds in the host plant. Host plants have been described as giving off a fermented odor when this insect is present.
Taxus Mealybug: Dysmicoccus wistariae was spotted on taxus in Amherst on 5/23/18 and again on 5/30/2018. 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.
Viburnum Leaf Beetle: Pyrrhalta viburni is a beetle in the family Chrysomelidae that is native to Europe, but was found in Massachusetts in 2004. Viburnum leaf beetle egg hatch was observed in Boston, MA on 5/4/2018. Viburnum leaf beetle larvae continue to feed and grow in size. (See Regional Reports above.) As the larvae grow larger, damage to plants becomes more significant. By early to mid-June, viburnum leaf beetle larvae will crawl down the host plant, enter the soil surface, and pupate. This typically occurs when the larvae are just under ½ inch in length. After pupation, by early July, adult beetles will emerge from the soil and begin feeding on viburnum foliage again prior to mating and laying eggs. This beetle feeds exclusively on many different species of viburnum, which includes, but is not limited to, susceptible plants such as V. dentatum, V. nudum, V. opulus, V. propinquum and V. rafinesquianum. Larvae, where they are present, may be treated with a product containing spinosad. Some viburnum have been observed to have varying levels of resistance to this insect, including but not limited to V. bodnantense, V. carlesii, V. davidii, V. plicatum, V. rhytidophyllum, V. setigerum, and V. sieboldii. More information about viburnum leaf beetle may be found at http://www.hort.cornell.edu/vlb/ .
Woolly Apple Aphid: Eriosoma lanigerum may be found on apple, crabapple, hawthorn, mountain-ash, pyracantha and elm hosts. The primary (winter) host is elm, on which aphids infest emerging spring leaf growth, causing leaves to curl or close into stunted, rosette-like clusters found at twig tips. Woolly apple aphid was observed on elm on 5/23/2018 in Amherst, MA. On apple and crabapple, this species of aphid colonizes roots, trunks, and branches in the summer and is commonly found near previous wounds or callous tissue. On roots the aphids cause swelled areas which can girdle and kill roots. The aphids, when found in above ground plant parts such as elm leaves, are covered with white wax. Eggs are the overwintering stage on elm, which hatch in the spring in time for the nymphs to infest elm foliage. Following a few generations on elm, the aphids will develop into a winged form which will disperse and seek out apple and crabapple. Multiple generations will occur on these alternate hosts in the summer and by the fall, a winged form will return to elm and mated females will lay eggs near elm buds.
Woolly Elm Aphid: Eriosoma americanum females lay a single egg in the cracks and crevices of elm bark, where the egg overwinters. Eggs hatch on elm in the spring as leaves are unfolding. A young, wingless female hatched from the egg feeds on the underside of leaf tissue. This female aphid matures and gives birth to 200 young, all females, without mating. These aphids feed and the elm leaf curls around them and protects them. Curled leaves, sheltering feeding, honeydew-producing aphids within, were observed on elm in Amherst, MA on 5/16/2018 and again on 5/23/2018. By the end of June, winged migrants mature and find serviceberry hosts. Another set of females is produced. These new females crawl to and begin feeding on the roots of serviceberry. Multiple generations occur on the roots of serviceberry through the summer.
Summer annual broadleaf and grassy weeds are beginning to appear in landscape beds. Directed spot treatment of glyphosate can be used at this time. If a preemergence herbicide was not applied to mulches, consider a tank mix of glyphosate and another preemergence herbicide labelled for landscape beds. Additional mulch can be added in areas where mulch is thin or nonexistent.
Tree seedlings are continuing to germinate and some locations may have seedlings that are 2 to 3 inches tall. These seedlings can be treated with pelargonic acid, Scythe. Another option would be to cut these seedlings with a gas-, electric- or battery-powered hedge shear at the soil or bark mulch surface. The organic/non-chemical products do not translocate and will product effective control of these young tree seedlings. Red maple seedlings are often the most common species of tree seedling. Seedlings in lawn areas will be managed by mowing and no action, mechanical or chemical, is required.
Japanese knotweed, Polygonum cuspidatum, has begun to emerge from rhizomes. Do not attempt to control this weed at this time as herbicide applications are not effective. Repeat cutting or mowing can be used as a non-chemical strategy and if that is the control strategy selected, then cutting and mowing should begin now. Repeat cutting or mowing should be done as regrowth reaches 4 to 6 inches.
Inspect areas of the landscape where new trees or shrubs, especially those that were field grown, have been planted in the last year. Look for perennial weeds that may be growing from the root ball. Canada thistle, mugwort, quackgrass, bindweed and horsenettle are some of the possible culprits. Applications of glyphosate as a directed spray should be done at the first sign of new seasonal growth.
Treat winter annual and perennial weeds in ornamental beds with glyphosate (Roundup Pro or equivalent) and glufosinate (Finale). Applications are easier if done before woody ornamentals leaf-out. The new growth of herbaceous perennial ornamentals can be very susceptible to spray drift, so exercise extreme caution. Non-chemical products containing clove oil, citric acid, acetic acid or orange extract can be used on small winter annuals but not on large winter annuals or perennials. Remember these organic/non-chemical products do not translocate and will not control established perennial weeds but will control young winter annual weeds. Many winter annuals are just beginning to flower and have not set seed and should be controlled now.

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