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 July 1. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.
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Scouting Information by Region
Environmental Data
The following growing-degree-day (GDD) and precipitation data was collected for an approximately one week period, June 16 through June 22. Soil temperatures and phenological indicators were observed on or about June 22. Total accumulated growing degree days (GDD) represent the heating units above a 50° F baseline temperature collected via our instruments for the 2016 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 |
Precipitation |
Time/Date of Readings |
||
|
1-Week Gain |
2016 Total |
Sun |
Shade |
|||
|
Cape Cod |
117 |
625 |
76 |
64 |
0.46 |
3:20 PM 6/22 |
|
Southeast |
111 |
626 |
71 |
66 |
0.48 |
3:55 PM 6/22 |
|
North Shore |
132 |
619 |
63 |
59 |
0.19 |
9:00 AM 6/22 |
|
East |
140.5 |
721.5 |
69 |
65 |
0.03 |
4:00 PM 6/22 |
|
Metro West |
134 |
666 |
66 |
62 |
0.12 |
5:45 AM 6/21 |
|
Central |
129 |
737 |
72 |
62 |
0.18 |
12:45 PM 6/21 |
|
Pioneer Valley |
136 |
735 |
72 |
65 |
0.12 |
3:00 PM 6/22 |
|
Berkshires |
121 |
630 |
70 |
63 |
0.47 |
11:00 AM 6/22 |
|
AVERAGE |
128 |
670 |
70 |
63 |
0.26 |
- |
|
n/a = information not available |
||||||
Phenology
Phenological indicators are a visual tool for correlating plant development with pest development. The following are indicator plants and the stages of bloom observed for this period:
| 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. |
| Itea virginica (Virginia Sweetspire)
|
Begin
|
Full
|
Full
|
Full
|
*
|
Full
|
Full
|
Begin
|
| Hydrangea macrophylla (Bigleaf Hydrangea)
|
Begin
|
*
|
*
|
*
|
*
|
*
|
*
|
*
|
| Hydrangea arborescens (Smooth Hydrangea)
|
*
|
Begin
|
*
|
Begin
|
*
|
*
|
Begin
|
*
|
| Tilia cordata (Littleleaf Linden)
|
Begin
|
*
|
Begin/Full
|
Full
|
Begin /Full
|
*
|
Full
|
*
|
| Rhus typhina (Staghorn Sumac)
|
*
|
*
|
Begin/Full
|
Begin/Full
|
Begin/Full
|
Begin/Full
|
Full
|
Begin
|
| Ligustrum spp. (Privet)
|
*
|
Full
|
Full
|
Full/End
|
Full
|
Full
|
Full
|
Full
|
| Sambucus canadensis (American Elderberry)
|
Begin
|
Begin/Full
|
Full
|
Full
|
Full
|
Full
|
Full
|
Begin/Full
|
| Catalpa speciosa (Northern Catalpa)
|
Begin
|
Full
|
Full
|
Full
|
Full
|
Full
|
Full/End
|
Full
|
| Syringa reticulata (Japanese Tree Lilac)
|
Begin
|
Full
|
Begin/Full
|
Full/End
|
Full
|
Full
|
Full
|
Full
|
| Philadelphus spp.(Mockorange)
|
Begin/Full
|
Full
|
Full/End
|
End
|
Full/End
|
End
|
End
|
Full/End
|
| Cornus sericea (Red Osier Dogwood)
|
*
|
End
|
Full
|
*
|
End
|
Full/End
|
End
|
Full/End
|
| Cotinus coggygria (Common Smokebush)
|
Full
|
End
|
Full
|
End
|
End
|
Full
|
Full
|
End
|
| * = no activity to report/information not available | ||||||||
Regional Notes
Cape Cod Region (Barnstable)
General Conditions: The weather for this reporting period has been lovely: clear, sunny, mild, and dry. In fact, it has been too dry for a while now. Unirrigated landscape plants are wilting in the mid-day sun. A line of thunderstorms brought some relief early Tuesday (June 21) morning but the rain gauge in Marstons Mills only recorded 0.46” while the weather station in Barnstable recorded 0.35”, not really enough to help plants that are newly planted or unirrigated. Many shrubs are flowering, including Rugosa rose, Mock orange, early Bigleaf hydrangeas that survived the winter, and Mountain laurel. Stella D’Oro daylilies are beginning to bloom and Peachleaf Bellflower (Campanula persicifolia) is in full bloom, along with Astrantia. Unirrigated lawns are turning brown.
Pests/Problems: Lack of adequate rainfall is certainly becoming an issue. Some towns are initiating summer water bans and some new plantings have been observed to be struggling with lack of irrigation, which is so important for good establishment of landscape plants, especially annuals with small root balls that dry out quickly.
Gypsy moth caterpillars are getting quite large. Most observed are either 5th or 6th instar, although some 3rds and 4ths can be found. There are pockets of complete defoliation in Dennis along Rt. 134. Large caterpillars were observed stripping spruce needles as the adjacent oaks were defoliated. Brewster, Harwich, Yarmouth, Centerville, Marstons Mills and Mashpee also have areas of total defoliation. I suspect Sandwich and Falmouth will also have areas of defoliation, although I haven’t personally observed it. Caterpillars were also seen feeding on white pine needles. The caterpillars will begin to pupate within the next week or two.
Second generation Lily leaf beetle adults are active and nymphs are feeding on true lily foliage. Rose slug sawfly has ended but Hibiscus sawfly larvae are turning perennial Hibiscus leaves to lace. Aphids, spittlebugs, leafhoppers, plant hoppers, earwigs, and spider mites are active. Asiatic garden beetles are up and feeding at night. June beetles are flying into screens at night.
A leaf spot has been observed on ‘Arnold Promise’ witch hazel.
Southeast Region (Hanson)
General Conditions: Nice summer weather this past week, with a brief thunderstorm on the 21st and a very brief shower on the 22nd, giving Hanson 0.48 inches of rain. Soils remain very dry and it is important to remind clients of the need to water their plants, especially trees defoliated by caterpillars. Some of those trees were defoliated last year too and drought stress will only compound their challenge to survive. The following plants are in full bloom: Northern catalpa, Stewartia pseudocamellia (Japanese Stewartia), Stewartia rostrata, Liriodendron tulipifera (Tuliptree), Styrax japonicus, Sinocalycanthus chinensis, Cornus kousa, Hypericum androsaemum ‘Mrs. Gladis Brabazon’,Weston hybrid azaleas, Hydrangea anomala petiolaris, Itea virginica, Spiraea sp., Calycanthus floridus (Common Sweetshrub), Indigofera sp., landscape roses, Kalmia latifolia, Lonicera sempervirens, Rosa rugosa, Clematis sp., Clematis, Salvia sp., Geranium sp., Anemone canadensis, Aruncus dioicus, Persicaria polymorpha, Doronicum sp., Lamium, Foxgloves, Allium, Nepeta sp., Baptisia australis and Baptisia hybrids, Dianthus sp., Tradescantia, Stella d’Oro and other early daylilies, Corydalis lutea, and Valeriana officinalis. Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) continue to provide the landscape with their colorful “smoke” and Kousa dogwoods continue to look fabulous. Unfortunately, similar to the 2015 season, the overwintering stems of most Hydrangea macrophylla were winter-killed this past February. This will make two years in a row that many gardeners will not be enjoying the beautiful flowers of Hydrangea macrophylla unless they planted more cold-hardy Hydrangea macrophylla hybrids like ‘Blue Billow’ or ‘Lady-in-Red’ or, one of the repeat blooming hydrangeas like, ‘Endless Summer’, which bloom on new wood.
Pests/Problems: Gypsy moth caterpillars are large and mostly in 5th & 6th instar (only the females go to a 6th instar, (however, curiously, there have been a few, minor observations of 3rd and 4th instars too). Many of the large late instar caterpillars are beginning to pupate and a few have pupated. However, many more gypsy moth caterpillars remain feeding heavily in many areas and in those areas, the trees are bare, and the caterpillar frass continues to fall covering everything below. Driving along Route 3 in the Plymouth area, especially the stretch near exit 5, the oak trees are stripped of leaves and the caterpillars are also feeding heavily on Pinus rigida (pitch pine). Gypsy moth caterpillars are also feeding on maples, white pine, spruce, apple, willow, crabapple, etc. Some landscape clients were complaining that they had had “their trees sprayed in May for the caterpillars” and were wondering what was going on. “Didn’t the spray work?” It took some careful explaining to make them realize that the there were two caterpillar problems: winter moth caterpillars, which finished feeding in late May, and gypsy moth caterpillars which began feeding in mid-May and continued into late June; two different caterpillars which may necessitate two separate spray applications.
Hibiscus sawfly larvae are active. Look for “holes” on the foliage of perennial hibiscus and examine the back of the foliage for the small, slug-like light, green sawfly larvae. If this insect is not managed early, the sawfly feeding will strip the foliage down to the veins. Bacillus thuringiensis (Bt) does not work on sawfly larvae.
Dogwood sawfly larvae remain active feeding on certain dogwood species like Cornus controversa and Cornus racemosa.
Monitor cherry for White Prunicola Scale crawlers and treat if needed.
Monitor for Andromeda lacebug feeding on Pieris japonica, and also monitor rhododendrons for rhododendron lacebug and evergreen azaleas for azalea lacebug. Lacebugs are active for most of the season and can cause serious damage to plants unless managed early.
The following insects remain active: Asiatic garden beetles, White pine sawyer beetle (Asian longhorned beetle look-alike), sunflower moth caterpillars (Homoeosoma electellum), Hemlock woolly adelgid, woolly beech aphid, cottony camellia scale on Meserve hollies and Taxus, Taxus mealybug, earwigs, planthoppers, mosquitoes, aphids, stink bugs,four-lined plant bugs, leafhoppers, lily leaf beetle, slugs, snails, wasps, pine spittlebugs, azalea whitefly, deer flies, horse flies, dog ticks and deer tick nymphs. Mosquitoes are abundant this year. Remind clients to empty containers of standing water or to treat with Bacillus thuringiensis israelensis (Bti). Beneficial insects, like hoverflies, lady bug beetles and six-spotted green tiger beetles, are also active. (See Tawny Simisky’s Insect section of the Landscape Message).
Sod webworm moths remain active on turf.
The following weeds are in full bloom: Japanese honeysuckle (Lonicera japonica - Massachusetts invasive plant), oxeye daisy, bouncing Bet, red and white clover and numerous grasses. Multiflora rose is ending bloom.
North Shore Region (Beverly)
General Conditions: The early part of this reporting period was relatively cool with day temperatures ranging between the low to mid 70s and night temperatures in the mid 50s. During the latter part of the reporting period, the temperatures went up to the mid 80s during the day. We gained 122 growing degree days at Long Hill. It was dry with the exception of Monday night when a quick thunderstorm passed through. We recorded 0.19 inches of rainfall from this storm. 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), Slender Deutzia (Deutzia gracilis), Sweet azalea (Rhododendron arborescens), Virginia sweetspire (Itea virginica), Magician Deutzia (Deutzia magicien), Oakleaf Hydrangea (Hydrangea quercifolia), Beautybush (Kolkwitzia amabilis), and Mountain Laurel (Kalmia latifolia). Herbaceous plants in bloom include: Peonies (Paeonia sp.), Redleaf rose (Rosa glauca), Virginia rose (Rosa virginiana), Baptisia (Baptisia australis), Nepeta (Nepeta sp.), Geranium (Pelargonium spp.), Aruncus (Aruncus dioicus), Corydalis (Corydalis lutea), Allium (Allium sp.) and Ox-eye daisy (Leucanthemum vulgare).
Pests/Problems: Woodchucks are causing some problems in the landscape. If you have problems with woodchucks in your garden, consider non-lethal control measures such as setting up a fence around the garden with a mesh size less than 2X2 inches. Phyllosticta leaf blotch was observed on Witchhazel (Hamamelis intermedia) last week and continues to defoliate the leaves. Leaf tip necrosis was observed on a Japanese stewartia, probably caused by anthracnose. If you notice this 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. 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: Temperatures have been comfortable over the last week, highs ranged from 76° F to 85° F (averaging 82° F) and lows ranged from 55° F to 63° F (averaging 58° F). We received minimal precipitation during the early morning of 21st amounting to only 0.03 inches. We gained 140.5 GDDs bringing us up to 721.5 GDDs for the year. We welcomed the summer solstice on the 20th with a full moon and 15 hours and 18 minutes of daylight. Thunder and lightning occurred on two occasions over the last week, during the overnight of the 17th/18th and during the early morning of the 21st. Plants in bloom include: Andrachne colchica (Caucasian spurge), Aruncus dioicus (goat's beard), Baptisia australis (blue wild indigo), Calycanthus chinensis (Chinese sweetshrub), Cornus kousa (Kousa dogwood), cultivars of Heuchera spp. (coral bells), cultivars of Hosta sp. (hosta), Hydrangea quercifolia (oakleaf hydrangea), Ilex pedunculosa (longstalk holly), cultivars of Lamium maculatum (spotted dead-nettle), Ligustrum vulgare (European privet, common privet), Lilium sp. (true lilies), Magnolia macrophylla (bigleaf magnolia), M. sieboldii (Oyama magnolia), M. virginiana (sweetbay magnolia), Pterostyrax hispidus (epaulette tree) Stewartia pseudocamellia (Japanese stewartia), Tilia platyphylla (bigleaf linden) and the sweat smelling ericaceous Zenobia pulverulenta (honeycup). Pollinators are extremely active, especially on many rose cultivars. The newly formed green fruit on many species of Pterocarya (wingnut) is very showy at this time of year. Asclepias syriaca (common milkweed) is just beginning to flower.
Pests/Problems: Soils are very dry due to the lack of precipitation; we have only received 0.08 inches of rain over the last two weeks. The extent of winter damage to the collections continues to be evident as we wait for plants to leaf out; dieback has been noted on many plants including: Abelia chinensis (Chinese abelia), Albizia julibrissin (silk tree), Amorpha fruticosa (indigobush), Buddleia alternifolia (fountain butterflybush), B. davidii (orange-eye butterflybush), many species of Callicarpa sp. (beautyberry), Clerodendrum trichotomum (Harlequin glorybower), Davidia involucrata (dove tree), many species of Hydrangea sp. (hydrangea), and some Lindera sp. (spicebush). Weeds in bloom include: Cynanchum louiseae (black swallowwort), Erigeron sp. (fleabane), Prunella vulgaris (common selfheal), Solanum dulcamara (bittersweet nightshade), and Tradescantia virginiana (Virginia spiderwort). Weeds in seed include: Alliaria petiolata (garlic mustard), Capsella bursa-pastoris (shepherd's-purse), and Stylophorum diphyllum [formerly Chelidonium majus] (celandine poppy). Ambrosia artemisiifolia (ragweed) has germinated. Powdery mildew has been spotted on dandelion (Taraxacum sp.). Arctium minus (lesser burdock) continues to grow throughout the landscape, exceeding heights of 5 feet. High populations of treehopper nymphs (Enchenopa sp.) can be found on almost every growing tip of Ptelea trifoliata (common hoptree).
Metro West (Acton)
General Conditions: Summer is officially here and so are the summer temperatures. High temps for each day in this recording period were in the 80’s with the highest of 89° recorded on the 20th. One again, precipitation was pretty much non-existent. The average monthly precipitation for June is 3.93” and recorded so far for the entire month has been 1.48”. Woody plants seen in bloom this past week are Buddleia spp. (Butterfly Bush), Catalpa speciosa (Northern Catalpa), Cotinus coggygria (Common Smokebush), Kalmia latifolia (Mountain Laurel), Kolkwitzia amabilis (Beautybush), Ligustrum spp. (Privet), Philadelphus coronarius (Sweet Mock Orange), Potentilla fruiticosa (Potentilla), Rhus typhina (Staghorn Sumac), Rosa rugosa (Rugosa Rose), R. 'Knockout' (The Knockout family of Roses), Rosa spp. (Rose), Sambucus canadensis (American Elderberry), Spirea japonica 'Alpina' (Daphne Spirea), Syringa reticulata (Japanese Tree Lilac), and Tilia cordata (Littleleaf Linden). Woody vines in bloom are: Clematis spp. (Clematis) and Lonicera spp.(Honeysuckle). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Achillea millefolium (Yarrow), Alchemilla mollis (Lady's Mantle), Aruncus aethusifolius (Dwarf Goat’s Beard), A. dioicus (Goat’s Beard), Astilbe spp. (False spirea), Campanula persicifolia (Peach-leafed Bell Flower), Campanula takesimana ‘Elizabeth’ (Bellflower), Centaurea montana (Cornflower), Chrysogonum virginianum 'Allen Bush' (Green and Gold), Clematis recta 'Purpurea' (Clematis), Coreopsis sp. (Tickseed), Dianthus deltoides (Maiden Pink), Digitalis purpurea (Foxglove), Filipendula sp. (Meadow Sweet), Geranium sanguineum (Cranesbill Geranium), G. ‘Johnson’s Blue’ (Cranesbill), Hemerocallis 'Stella D'Oro' (Daylily) and H. spp. (Daylily), Heuchera spp. (Coral Bells), Hosta spp. (Plantain Lily), Leucanthemum sp. (Shasta Daisy), Lilium spp. (Lily), Lychnis coronaria (Rose Campion), Nepeta spp. (Ornamental Catmint), Oenothera macrocarpa (Ozark Sundrops), Paeonia spp. (Peony), Penstemon digitalis 'Husker Red' (Beardtongue), Perovskia atriplicifolia (Russian Sage), Platycodon grandiflorus (Balloon Flower), Salvia nemerosa (Salvia), Saponaria ocymoides (Rock Soapwort), Thymus praecox (Thyme), Tradescantia sp. (Spiderwort), and V. umbrosa 'Georgia Blue' (Speedwell).
Pests/Problems: The lack of any rain is a concern for our trees and shrubs in the landscape especially compounded with any other stresses such as winter or gypsy moth caterpillars, hemlock woolly adelgid, snow and ice removal applications, or anthracnose on our plants.Pine Sawyer Beetles have recently emerged and are often very confused with the Asian Longhorned Beetle but can be distinguished by its single white dot found at the base of its wing cover. Asian Longhorned Beetles have yet to emerge but will soon! Ticks and mosquitoes are active and feeding. Gypsy moth caterpillars are active and feeding.
Central Region (Boylston)
General Conditions: Dry, Dry, Dry! Non-Irrigated turf is slipping into a dull brown dormancy. Plants in bloom in the gardens include Zenobia pulverulenta.
Pests/Problems: Gypsy moth caterpillars are chewing their way through oak leaves and nibbling at other woody plant leaves as well. Larvae of Lily Leaf Beetles are feeding on assorted monocots. Imported willow beetles are active on Willows. Spider Mite and leafhopper populations are growing, three-lined potato beetles and golden tortoise beetles have been spotted. Chipmunks are prolific!
Pioneer Valley Region (Amherst)
General Conditions: Beautiful, but dry, summer weather dominated this past reporting period in the Pioneer Valley. We reached the summer solstice on June 20 and the long days are surely worth celebrating. High temperatures were consistently in the middle to upper 80s with minimal humidity while nighttime temperatures cooled into the middle to lower 50s. Overall, the past week was ideal for outdoor activities. However, the lack of rainfall has now become a major concern. June is on pace for below average precipitation and after a below-average May, drought stress of woody and non-woody ornamentals will become a problem if we don’t receive rain in the next few weeks. According to the Northeast Regional Climate Center, the Pioneer Valley has received only 50-75% of normal precipitation from March through May of 2016. At present, plants are not wilting or showing symptoms of drought stress but temperatures will only continue to climb as we enter July. June began on a positive note, with a soaking rain followed by up to a 0.5″ in some locations a week later. However, since that first week of the month, accumulations from passing showers have been paltry at best. Turfgrasses have browned dramatically over the past week. The lack of rain has suppressed mosquitoes and we have passed the peak of black fly season, so biting insect populations are minimal right now in most locations.
Pests/Problems: The most recent update from the U.S. Drought Monitor (http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA) shows that almost the entire Pioneer Valley is suffering from drought conditions. Eastern Hampden County has even entered the D2 stage, categorized as “severe drought”. Continue to regularly irrigate young and recently transplanted trees and shrubs, especially those in full sun and subjected to persistent winds. Transplanted trees and shrubs should be watered once weekly during the growing season while those established for one or more years may only need bi-monthly or once monthly watering during extended dry periods like the one we’re currently in. The dry weather has helped to suppress many fungal pathogens that can wreak havoc on the landscape during wet years. Foliar blights caused by anthracnose fungi are not as abundant. Sycamores that struggled to leaf out are now filling out. Other leaf spot and blotch pathogens are slowly taking hold.
Berkshire Region (Great Barrington)
General Conditions: After a week of chilly and windy, a large reversal occurred this past week as temperatures soared into the 80s, including three days of near 90° F. Besides the heat, a lack of rainfall – except for the early morning of June 21 when 0.47 inches of rain fell, as measured at the Great Barrington monitoring site – has left soils very dry. Mid-Berkshire County had even less rain from the June 21 thunderstorm as 0.08 inches was reported. Some lawns are showing the effects of low soil moisture but the general landscape appears lush and vibrant with Cornus kousa putting on a great show.
Pests/Problems: The dry conditions may have influenced the level of pest pressure as it does not seem as great as in past years. Among the pests reported earlier and still active are; woolly beech aphid, imported willow leaf beetle (adult stage), lily leaf beetle (adult), hydrangea leaf tier (pupating), rose slug, aphids (moderate infestation on Liriodendron tulipifera), leaf hoppers, and cutworms. Lady beetle larvae were found on some of the aphid infested plants. Black vine weevil was captured in burlap traps. For those not familiar with this trap, it consists of a three-foot long piece of burlap folded according style and wrapped around the base of rhododendron stems. The adult weevil, which feeds on edges of rhododendron leaves at night, hides in the folds of burlap during daylight hours. Euonymus scale crawlers are still present though many have settled. White spotted pine sawyer beetle was observed this past week. It is similar in appearance to the Asian longhorned beetle but is a native beetle found in dead or diseased pines. It should be noted that the Asian longhorned beetle has not yet been found in Berkshire County. Disease problems observed this week included black spot on roses, apple scab and cedar apple rust on crabapples, powdery mildew on Physocarpus (ninebark), and Weir’s cushion rust (Chrysomyxa weirii) on new needles of white spruce. Deer browsing in home landscapes has picked up, with hostas being a favored dining target. This may be due to a preference for the more succulent vegetation in managed landscapes as opposed to the now mature vegetation in natural landscapes. For the first time this year, there is noticeable browning of some lawns. This is most likely the result of a combination of low mowing and the dry conditions this spring. Setting mowing height at 3 inches or higher, along with irrigation, is the best way to prevent or reduce the occurrence of browning. A couple of young trees at one monitoring site were on the doorstep of death. Examination of the specimens, which were planted about a year ago, revealed a very tight mass of roots. The saplings had been container grown and were clearly root bound, with many girdling roots. The root mass was so tight that it is likely that water could not penetrate into the root ball. When root bound container-grown plants are encountered, slice through the root system with a sharp knife from top to bottom in four to eight locations around the root ball and gently pull the roots away from the tree trunk. Girdling roots should be cut or straightened at planting time.
Regional Scouting Credits
- CAPE COD REGION - Roberta Clark, UMass Extension Horticulturist for Barnstable County - Retired, 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 - 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 pathogens of interest seen in the UMass Extension Plant Diagnostic Lab:
Stem cankering of Kwanzan cherry (Prunus serrulata ‘Kwanzan’) by Botryosphaeria and Phomopsis. Tree is 20-years-old and has been present at the site for nearly as long. On scattered stems in the canopy, leaves wilted and became brown in recent weeks. The tree leafed out and flowered normally prior to the canopy dieback. Canopy dieback of flowering cherry has been widespread in the region this season. In some cases, winter injury is the suspected cause. In roughly half of those cases, stem cankering fungi have also been detected.
Cryptocline needle blight, caused by Cryptocline taxicola, and an infestation of the fletcher scale (Parthenolecanium fletcheri) on English yew (Taxus baccata ‘Adpressa’). Shrub is 15-years-old and has been present at the site for 12 years. Over this past winter, needles became yellow to brown and were prematurely shed. Cryptocline can be damaging when the fungus is well distributed in the canopy, causing a shoot and needle blight. The fletcher scale infestation, which is common on yews, was minor in extent.
Needle blight of eastern white pine (P. strobus) caused by Septorioides strobi. Tree is roughly 35-years-old and grows in full sun in a sandy loam soil. In mid-May the tree exhibited symptoms similar to that of many white pines in the region: yellowing/browning and premature shedding of older needles. The tree resides in a large mulched bed and has not been subjected to de-icing salts.
Stem and branch cankering of sugar maple (Acer saccharum) caused by Steganosporium ovatum. Tree is approximately 80-years-old and has been present at the site its entire life. In spring of 2016, dieback was observed at ends of upper canopy limbs. Some branches that were killed were 4” in diameter and were scattered throughout the upper and lower canopy. The symptoms were not observed in previous years. Little is known about Steganosporium, aside from the occurrence on sugar maples. It’s believed to be a secondary cankering pathogen attacking trees stressed by insects (e.g. sugar maple borer) and disease (e.g. Armillaria). The submitted stems and branches were coated with black-colored spore masses that had ruptured through the bark.
Brown needle spot, caused by Lecanosticta acicola (formerly Mycosphaerella dearnessii), and infestation of the pine bark adelgid (Pineus strobi) on white pine (P. strobus). The tree is one of several in a forest setting, roughly 20-years-old, in loamy clay soils. The trees are not shaded by overstory trees. Extensive needle browning and shedding took place this spring but symptoms were observed for the past few years.
Bifusella needle cast, caused by Bifusella linearis, on white pine (P. strobus). Tree is 20-years-old and has been present at the site for over 10 years. The canopy appeared chlorotic last fall and this spring all of the older needles browned and were prematurely shed. The current season’s candles are healthy and have continued to develop. Tree is growing in full sun near the ocean but is far enough away where salt spray is not a concern.
Root and crown rot of rhododendron (Rhododendron ‘PJM’) by Phytophothora. Plant is three-years-old and is one of many in a nursery setting. Leaves at shoot tips throughout the canopy began to wilt, curl and turn brown in late May. There was no evidence of a foliar or shoot blight on the submitted specimen. The plant was potted too deep and girdling roots had developed. More importantly, lesions on the main stem were detected at the base, just above and below the soil line.
Needle cast, caused by Ploioderma lethale, of Austrian pine (Pinus nigra). Tree is 20- to 25-years-old and has been present at the site for nearly as long. In spring of this year, nearly the entire canopy became brown with very few green needles remaining. Another Austrian pine on the property appears healthy. Needle tips were straw-colored to brown and had numerous small, black-colored pads of fungal tissue that swell during wet and mild weather to release large volumes of clear-colored spores. The tree resides in a coastal setting in full sun with a loamy clay soil that is moderately well-drained.
Stem cankering, caused by Diplodia cupressi, on Leyland cypress (x Cupressocyparis leylandii). Tree is roughly 15-years-old and exhibited canopy dieback during the winter months. Needles became pale green to brown and wilted on the shoots. This pathogen has only recently been associated with Leyland cypress in the region, but at present, does not appear particularly aggressive in most landscape settings.
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:
First, a note about beneficial insects: as a friendly reminder, it is always good to re-familiarize ourselves with those insects who, by their acts of predation, parasitism, and sometimes excessive killing (some beneficial insects will kill more of their own prey than they can eat!), can be key allies in the management of unwanted insect pests in the landscape. As we reviewed last week in the Landscape Message and this week on the Landscape, Nursery, and Urban Forestry Facebook page, beneficial insects can also be important pollinators. Preserving these insects for the benefits they provide starts with recognition and differentiation from pest insects. For an excellent review of some of these beneficial insects with great photographs, visit: http://cru.cahe.wsu.edu/CEPublications/EM067E/EM067E.pdf. (This great publication from Washington State University Extension highlights many natural enemies/beneficial insects that we also have here in the Northeast.)
- Gypsy Moth: Caterpillars continue to feed on the leaves of hosts, favoring oak, but also feeding on maple, birch, poplar, and willow when in close proximity to oak, along with others. Coniferous hosts become a part of their menu when other resources are stripped bare. Reports of gypsy moth caterpillars feeding on eastern white pine have come in from areas such as, but not limited to, Hanson (see Southeast Region report), Framingham, Brimfield, Plymouth, and areas of the Cape (see Cape Cod Region report). Other conifers reportedly being fed on by gypsy moth this year include spruce.
Caterpillar numbers are elevated in certain areas this year, corresponding to locations with high numbers of egg masses laid last season. Therefore, caterpillar presence is patchy across the landscape and not all locations are experiencing high gypsy moth populations. Reports of gypsy moth caterpillar activity continue to be made in certain locations. Spotted areas in towns including but not limited to Sturbridge, Monson, Uxbridge, Brimfield, Charlton, Northborough, Westborough, Plymouth, Carver, Hanson, Kingston, Wareham, Sharon, Winchendon, Framingham, West Bridgewater, Braintree, Rowley, Georgetown, Ipswich, Newbury, Boxford and Topsfield are reporting continued and elevated caterpillar activity paired with defoliation. Defoliation (mostly oaks) has been observed by motorists driving in certain areas on Rt. 3 (Plymouth area), I-495 (Acton, Littleton, and Worcester areas), and the MA Turnpike (I-90) near Charlton and points west. Caterpillars have been observed to be in the 5th and 6th instars, and are beginning to pupate in some areas. Feeding will continue until all caterpillars have pupated. Adult emergence will occur primarily in July, but could begin as early as next week, at which time mating and egg-laying will take place. At this point, Bacillus thuringiensis Kurstaki will not be effective on large caterpillars. The active ingredient spinosad may be more effective at this time, however larger caterpillars are more difficult to kill. This active ingredient should not be applied to flowering plants as it is toxic to pollinators until it dries.
The continued hope is that the fungus, Entomophaga maimaiga, and the NPV virus will catch up to the increasing populations of gypsy moth in these areas and provide some relief. That remains to be seen for the larger proportion of sites impacted by caterpillar feeding. There are few scattered reports of some caterpillars exhibiting signs of Entomophaga infection and some succumbing to the NPV virus, but unless the pathogens become more common in this year’s crop of caterpillars, it may not have the desired effect we hope for next year. Monitoring the landscape for large numbers of tan-brown egg masses laid on hosts by the adult females in July will help folks predict what to expect of these caterpillars next season and to plan management for the spring.
- Andromeda Lacebug: Stephanitis takeyaiis active on Japanese Andromeda and will continue into September. Inspect plants known to have S. takeyai in the past (or exhibiting yellow stippling on the upper leaf surface) and inspect undersides of leaves for this season’s lacebugs. 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.
- Arborvitae Leafminer: Argyresthia thuiella is pupating now and small, silvery-tan moths will be active soon in most areas. If arborvitae is exhibiting numerous browned needle tips, shake the branches to observe whether or not the tiny moths take flight. If large numbers of moths are present, the plant may be treated with a pyrethroid insecticide, as necessary. The use of yellow sticky cards to monitor for this insect has not been found to be successful.
- Asiatic Garden Beetle: Autocerica castanea adults are active. These rusty-red colored beetles are bullet-shaped and active at night. They are often attracted to porch lights. They feed on a number of ornamental plants, defoliating leaves by giving the edges a ragged appearance and also feeding on blossoms. Butterfly bush, rose, dahlia, aster, and chrysanthemum can be favored hosts. When levels of damage reach a management threshold, pyrethroid- based insecticides may be necessary. Read and follow label instructions and avoid harming non-target organisms.
- Azalea Lacebug: Stephanitis pyrioidesis active on evergreen azaleas. This insect may be more damaging on plants located in warm, sunny locations. Like andromeda lacebug, this insect will remain active into the fall. Plants in hot, dry, sunny sites may be severely impacted by mid- August. Horticultural oil sprays targeting the undersides of the foliage can be very effective for this pest.
- 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 as adults are feeding. Burlap laid around the base of plants during the time adults are active, now through August, can be inspected weekly for adult weevils which can be killed before egg laying.
- Cottony Taxus/Camellia Scale: Pulvinaria floccifera nymphs are actively feeding and now empty white, oblong cottony egg sacs can be seen on host foliage. Holly, camellia, Taxus, rhododendron, certain maples, English ivy, and others can be hosts of this pest. Inspect leaf undersides for this soft scale. Treat with a horticultural oil spray at the summer rate, targeting twigs and foliage where the pest is residing.
- Dogwood Borer: Synanthedon scitula adult moths are active and will be until September. Flowering dogwoods (and others) exhibiting dieback beginning in the crown and working its way downward may be attacked by this pest. Avoid mechanical injury to these host plants at this time, either accidental or by pruning, as the adult female moths are attracted to these wounds where they will lay their eggs. (Wounds provide easy entry for newly hatched larvae.)
- Dogwood Sawfly: Macremphytus spp. caterpillars are actively feeding. Inspect chewed foliage of dogwood, particularly Cornus racemosa (gray dogwood) for caterpillars skeletonizing the leaves. Foliage will be consumed down to the mid-vein. Spinosad based products are successful where needed, however small infestations can be removed by a gloved hand and destroyed. Do not apply spinosad to plants in flower.
- Eastern Tent Caterpillar: Eastern tent caterpillar larvae will be reaching the pupal stage which will last for a few weeks. Adults will emerge by the end of this month and early July to mate and the female will lay her egg mass on the branches of host plants. Egg masses of the eastern tent caterpillar have a rounded edge. Forest Tent Caterpillars are also reaching the pupal stage and adults will appear shortly to mate. Females will lay their egg masses with a square edge on host plant twigs.
- Emerald Ash Borer: 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). Adults will be emerging at this time. 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 .
- 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 of the previous year, and eggs have hatched. Monitor susceptible hosts for small, inch-worm like caterpillars by shaking branches over a light colored surface. Where populations are low, no management is necessary. Treat with Bacillus thuringiensis Kurstaki if needed. Caterpillar feeding will end by early-July.
- Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. Infested trees may be treated with a summer rate horticultural oil spray as weather conditions allow. Be cautious when pruning or removing infested hemlocks as to avoid accidentally transporting eggs and nymphs that are present at this time.
- Lily Leaf Beetle: Larvae are actively feeding. Pyrethroids can be used against adult beetles, whereas spinosad products are most effective against the larvae.
- Mountainash Sawfly: Pristiphora geniculata larvae will be actively feeding on foliage. Examine leaflets of the plant in shady areas for clusters of yellow-green larvae. Remove clusters by hand where possible and treat with a product such as spinosad when present in high numbers. This sawfly is capable of consuming all foliage down to the midvein.
- Rhododendron Borer: Synanthedon rhododendri clearwing moths will be active soon. Female moths can lay eggs at the base of shoots near the ground. Tiny, wood-boring caterpillars will emerge and chew an entrance hole through the bark. Inspect the base of shoots, old pruning sites, and branch crotches for sawdust, which may indicate the presence of this pest. If timed correctly, an application of a pyrethroid on larvae before they enter the shoot may be helpful.
- Rhododendron Lacebug: Stephanitis rhododendri is active on rhododendron but also is a pest on other broadleaf evergreens along with aforementioned Azalea lacebug, S. pyrioides. Horticultural oil sprays targeting the undersides of the foliage can be very effective for these pests that cause leaf-yellowing/stippling/chlorosis as they feed with their piercing-sucking mouthparts.
- Roseslugs: Activity of the roseslug larvae has concluded for this season.
- Taxus Mealybug: Dysmicoccus wistariae are actively feeding. Inspect the inner branches of yew (Taxus) for the white, soft-bodied insects. Honeydew and sooty mold may also be present. When present in large numbers, plants may become stunted and unsightly. If needed, treat the inner branches with a horticultural oil spray at the summer rate.
- Viburnum Leaf Beetle: Larvae are mostly finished feeding and will be moving to the soil to pupate. Any remaining larvae may be treated with a product containing spinosad if found. Adults will emerge by mid-July and will resume feeding on the plant. Adult beetles may be targeted with a pyrethroid. Planting species of viburnum that are most resistant to the viburnum leaf beetle can help manage this pest. Resistant varieties include V. bodnantense (dawn viburnum), V. carlesii (Koreanspice viburnum), V. davidii (David viburnum), V. sieboldii (Siebold viburnum), and others. Highly susceptible species of viburnum frequently attacked by this beetle can include V. dentatum (arrowwood viburnums), V. opulus (European cranberrybush viburnum), and V. rafinesquianum (Rafinesque viburnum).
- White Prunicola Scale: crawlers are active and can be treated with a horticultural oil spray. This is a common pest on Japanese cherries, particularly in the eastern parts of the state.
- White Spotted Pine Sawyer (WSPS): Adults are emerging and will do so throughout July, depending on local temperatures. This is a native insect in Massachusetts and is usually not a pest. Larvae develop in weakened or recently dead conifers, particularly eastern white pine (Pinus strobus). However, the white spotted pine sawyer looks very similar to the invasive Asian Longhorned Beetle, Anoplophora glabripennis, ALB. ALB adults do not emerge in Massachusetts until July and August. Beginning in July, look for the key difference between WSPS and ALB adults which is a white spot in the top center of the wing covers (the scutellum) on the back of the beetle. White spotted pine sawyer will have this white spot, whereas Asian longhorned beetle will not. Both insects can have other white spots on the rest of their wing covers, however the difference in the color of the scutellum is a key characteristic. 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 captured an Asian longhorned beetle (particularly beginning in July and August) or have seen damage caused by this insect, such as exit holes, 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. 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.
A note about Deer 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. Adults and nymphs are active and 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 Laboratory of Medical Zoology (www.tickdiseases.org) and click on the red Test a Tick button for more information.
Report by Tawny Simisky, Extension Entomologist, UMass Extension Landscape, Nursery, & Urban Forestry Program
Management Practices
Plant of the Week: Itea virginica
Itea virginica is a native deciduous shrub growing 3-5’ tall and wide, growing larger in the wild. Plants are best grown in full sun to part shade in an average, well-drained soil, but are tolerant of heavy shade, wet soils, and a range of soil conditions. The fragrant white flowers are borne on 2-6” long racemes in June. Flowers are formed on the previous season’s growth so plants should not be pruned until after flowering. Leaves are medium green and glabrous in the summer turning yellow, orange, red, or reddish purple in the fall. Fall color can be quite showy. Itea virginica has no serious insect or disease problems but can form suckers from the roots which need to be kept in check. Cultivars can provide more compact forms or specific fall colors. Good choice for wet areas in the landscape.
Report by Mandy Bayer, Extension Assistant Professor, UMass Stockbridge School of Agriculture
Landscape Turf
Insects
Dry weather adding challenges
Many areas in New England are facing moderate drought already, with rainfall totals for the year running 3 to 6 inches below "normal". This may well have an impact on turf insect activity, at least until we see some steady restorative rainfall.
Chinchbugs prefer sunny areas with soils that drain well, along with plenty of thatch. They can feed on any cool season turfgrass, and are often found on creeping bentgrass that is maintained at lawn height. (While bentgrass is not normally a preferred species in lawn settings, there are some native bentgrasses that seem to thrive in lawns. Sadly, I have some in my own lawn.) Bentgrass in a lawn-type maintenance tends to be very thatchy, providing plenty of "safe haven" for the chinchbugs.
Chinchbugs are usually active from early June through mid September, with adults and immatures active at the same time. Chinchbugs go through gradual metamorphosis, which means the immature stages ("nymphs") look just like the adults and feed in the same way - using piercing and sucking mouthparts to extract nutrients from the plants. As soon as you see evidence of chinchbug feeding activity, you can get some relief by applying a pyrethroid to the affected area. Most of the other common turf insecticides either do not have chinchbugs on the label or only claim "suppression", whatever that means.
Adults of white grubs are becoming active in many parts of the region. European chafer adults are flying now in some of the more southern areas of New England, and I expect they will be noticeable in the Mid Coast Maine area soon. European chafer adults are nocturnal but you often see flights emerging around twilight, and sometimes huge numbers of adults are attracted to a wide range of shade trees. While I have not had reports of it yet, oriental beetles are probably flying now. (They fly both in the day and at night.) And Japanese beetle adults will be flying very soon. We usually consider July 4th as the time when we become aware of the beetles, but they should start showing up in Japanese beetle traps within the next few days. They fly readily during the day, especially sunny, warm days, so don't be surprised if you see some on Sunday or Monday!
If the dry weather continues well into the summer, beetles of many of the white grub species may delay egg-laying. The females are able to detect when soil moistures are very low, and instead of laying eggs "on schedule", they will hold on to those eggs until soil moisture conditions improve. If this happens, the normal window for application of a neonicotinoid (mid June to early August) may be too early to achieve good grub control. It is too early to tell whether this will be the case, but stay tuned!
Also keep in mind - if you are planning to use a neonicotinoid as a preventive treatment against white grubs, you normally are counting on some of that active ingredient to be taken into the plant (taking advantage of the systemic nature of the neonicotinoids). But if the plants are in summer dormancy as a result of low - or no - rainfall, they are not able to take up the active ingredient.
Report by Pat Vittum, Professor and Extension Entomologist, UMass Stockbridge School of Agriculture and Associate Director, UMass Center for Agriculture, Food and the Environment.
Additional Resources
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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
