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Landscape Message: July 15, 2016

July 15, 2016
Issue: 
16

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 bi-weekly July through September. The next message will be available on July 29. To receive immediate notification when the next Landscape Message update is posted, be sure to join our e-mail list.

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


Scouting Information by Region

Environmental Data

The following growing-degree-day (GDD) and precipitation data was collected for an approximately two week period, June 30 through July 13. Soil temperatures and phenological indicators were observed on or about July 13. 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
(°F at 4" depth)

Precipitation
(2-Week Gain)

Time/Date of Readings

2-Week Gain

2016 Total

Sun

Shade

Cape Cod

306

1054

72

68

2.48

6:30 AM 7/14

Southeast

255

1,003

80

70

0.92

3:00 PM 7/13

North Shore

264

1003

67

63

0.82

9:00 AM 7/13

East

290

1153

75

70

0.72

4:30 PM 7/13

Metro West

281

1082

68

64

0.36

5:45 AM 7/13

Central

268

1149

69

68

0.63

12:50 PM 7/13

Pioneer Valley

294

1177

77

70

0.94

1:00 PM 7/13

Berkshires

255

1002

74

68

1.96

11:00 AM 7/13

AVERAGE

277

1078

73

68

1.10

-

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.
Hibiscus syriacus (Rose-of-Sharon) * * * * * * Begin *
Buddleia davidii (Butterfly Bush) * * * Begin Full * Begin *
Campsis radicans (Trumpet Vine) * Full Begin Begin/Full Full * Full Begin
Oxydendrum arboreum (Sourwood) Begin Begin/Full Begin Begin/Full Full Begin Full *
Koelreuteria paniculata (Goldenrain Tree) * * Full Begin/Full * * Begin *
Hydrangea paniculata (Panicle Hydrangea) Begin/Full Begin * Full/End Full Begin Begin Begin
Itea virginica (Virginia Sweetspire) End End End End * * * Full/End
Hydrangea macrophylla (Bigleaf Hydrangea) Begin/Full Full Begin End Full * Full *
Hydrangea arborescens (Smooth Hydrangea) Full Full Full End Full Full/End Full Begin/Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: This two week reporting period has seen fluctuating weather. The month started off quite warm with thunderstorms on the 1st, which gave the Cape much needed rain. In Marstons Mills, 1.29” was recorded in the rain gauge. On July 5th, the Cape experienced a day-long rain event that left 0.91” in the Mills, while Harwich received 1.45”, Yarmouth received 1.2” and Hyannis received 0.88”, The weather turned cool, foggy, and damp from the 8th to the 11th, giving another 0.25”. In spite of this precipitation, the Cape is still classified as Abnormally Dry while the rest of the state is classified as under Drought conditions. Soils at a depth of about 6” are quite dry in Marstons Mills. Many perennials are in bloom in the landscape, with daylilies, Black-eyed Susans, and Coreopsis all in bloom. Oak leaf and Panicle hydrangeas are all in bloom. Many lace-cap type hydrangeas appear to have escaped the worst of the past winter while Mop head hydrangeas are not as wonderful except along the shore and in other protected locations. Unirrigated lawns are brown.

Pests/Problems: Male gypsy moth are flying! In areas that saw heavy defoliation, there are literally hundreds of brown moths searching for the females, which do not fly. Female moths will be found on tree trunks, fences, houses, or where ever they pupated. As of this writing, I haven’t observed a female and they may not have emerged from pupation quite yet but certainly will shortly. Females are quite large and are white. When egg laying begins, you will see peanut butter colored egg masses wherever the female was when she pupated. If the number of flying moths are an indication of next year’s caterpillar population, we’d better hope for a wet spring to activate the Entomophaga fungus.

Japanese and Oriental beetles are active and can be found on various roses, annuals, perennials, and fruits such as grape and raspberry. Asiatic garden beetle is active but feeds at night, so is often not seen damaging plants. Various leaf hoppers, plant hoppers, aphids, and mites are all active. Sharp shooter leaf hoppers can be found on Rhododendron. Four lined plant bug is active on annuals and perennials. Hibiscus sawfly larvae are just about done feeding on perennial Hibiscus. Mosquitoes are still biting, especially in areas near lakes, ponds, and bogs. Green head flies are also biting, especially on North side beaches. Rabbits, voles, and chipmunks are browsing on perennials, annuals, and vegetables. In the vegetable garden, Squash vine borer moths are flying and laying eggs on summer squash, pumpkins, and other winter squash except for butternut, which is not affected. Cucumber beetles are heavy on cucumbers and squash.

There is little in the way of common disease problems except on such plants as susceptible roses that are irrigated. Black spot can be seen on those plants. Powdery mildew is beginning to show up on Evening Primrose, Phlox, and Beebalm now that more humid weather is upon us.

Southeast Region (Hanson)

General Conditions: Cooler weather over the first week of July, gave way to hot, humid weather and very little rain. Hanson received 0.92 inches of rain over the past two weeks and soils are very dry. Plants in unirrigated soils are becoming drought-stressed and most of MA is under a drought watch except Cape Cod and the westernmost part of the state. Continue to remind clients to water trees and shrubs planted this season and trees defoliated by caterpillars. Drought stressed trees are prone to increased problems, especially defoliated, drought-stressed oaks that might become a target for the two-lined chestnut borer. The following plans are in full bloom: Oxydendrum arboreum (Sourwood Tree), Stewartia pseudocamellia (Japanese Stewartia), Stewartia ‘Scarlet Sentinel’, Catalpa bignonioides (Southern Catalpa), Catalpa ovata (Chinese catalpa) Rhododendron maximum, Campsis radicans, Weston hybrid azaleas, Amorpha canescens (Leadplant), Indigofera sp., Clematis, Roses, Spiraea sp., Hydrangea arborescens (Smooth Hydrangea), Hydrangea quercifolia (Oakleaf hydrangea), Hydrangea macrophylla, Hydrangea paniculata ‘Praecox’ and other early cultivars, Rubus odoratus, Campanula sp., Persicaria polymorpha, Astrantia major, Achillea, Alchemilla mollis, Lamium, Asiatic lilies, Heliopsis sp., Platycodon grandiflorus, Asclepias tuberosa, Asclepias syriaca (common milkweed), Actaea (formerly Cimicifuga) racemosa, Shasta daisies, Deinanthe caerulea, Perovskia atriplicifolia, Yucca filamentosa, Astilbe, Liatris spicata, Hollyhocks, Corydalis lutea, daylilies, Hosta, Coreopsis sp., Kniphofia sp., Lysimachia clethroides, Filipendula venusta, Lysimachia ciliata, Monarda didyma (Beebalm) and Spigelia marilandica (Indian Pink). Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) continue to enhance the landscape with their colorful “smoke”. Staghorn sumac fruit is red. There are a few Kousa dogwoods remaining in bloom.

Pests/Problems: Gypsy moth caterpillars began pupating in late June – early July and a few stray caterpillars were observed actively feeding on July 8th. Male gypsy moths began to emerge around July 4th and continue to emerge now, by the thousands! The landscape is littered with them flying around! Females began to emerge after the males and egg-laying has begun. Without sufficient moisture, the insect-attacking fungus, Entomophaga maimaiga, while killing some late stage caterpillars, was not present enough to do significant damage to this season’s gypsy moth caterpillar population. There are now thousands and thousands of eggs being laid, and unless next spring brings rain to activate the fungus, there is the potential for an epic amount of gypsy moth caterpillars next year. (See Tawny Simisky’s Insect section of the Landscape Message). Defoliated trees are slowly leafing out and, as noted above, need water to alleviate drought stress and to help ‘push out’ new growth. A curious observation in Hanson, MA: staff from Dr. Elkinton’s UMass lab, observed the rare black-billed cuckoo in a forested area. This bird is known to eat “hairy caterpillars” and the thinking is, that this was a very good year for “hairy caterpillars”, hence the rare sighting: http://www.audubon.org/field-guide/bird/black-billed-cuckoo.

Japanese beetles were observed around July 11th, a bit later than usual and were found feeding on roses, and other usual hosts, along with Oriental beetles and Asiatic garden beetles.

Asian longhorned beetle look-alikes, like the White-spotted Pine Sawyer and Graphisurus fasciatus (Longhorned Beetle) are active. However, start scouting and monitor host trees for Asian longhorned beetles which may begin to emerge in July: https://ag.umass.edu/fact-sheets/asian-longhorned-beetle.

The caterpillar-like larvae of various sawflies can cause significant damage to plants, if not managed. Monitor white pine, Mugo pines etc. for the Introduced Pine Sawfly (black head, black body with white and yellow spots).

Monitor new foliage of Rhododendron maximum and R. catawbiense, as well as the foliage of roses and raspberries for the Sharpshooter leafhopper or red-banded leafhopper. Continue to monitor for Hibiscus sawfly larvae which are almost done. Four-lined plant bug damage is very noticeable now as brown circular lesions, coalescing together, sometimes mistaken for a disease. Monitor Azaleas for Azalea bark scale, eggs and crawlers.

The following insects remain active: Spider mites, lily leaf beetle, Cottony Camellia/Taxus scale; sunflower moth caterpillars (Homoeosoma electellum); Taxus mealybug; earwigs; azalea, rhododendron and Andromeda (Pieris) lacebugs; aphids; slugs; snails;leafhoppers; wasps; hornets; mosquitoes; deer flies; horse flies, deer tick nymphs and dog ticks.

The dry weather seemingly has helped slow down plant disease. Powdery mildew is starting to show up on Cornus florida and various Lonicera and there is some black spot on roses.

North Shore Region (Beverly)

General Conditions: This reporting period saw the end of June and the first two weeks of July. June was unusually dry with less than 2.5 inches of rain recorded at Long Hill during the month. Temperatures during this reporting period were in the high 70s and 80s during the day and rising to 91 degrees on July 6. Night temperatures were in the high 50s to low and mid 60s. Long Hill gained 264 growing degree days (GDD) during this two week reporting period, and received approximately 0.82 inches of rainfall. Woody plants seen in bloom include: Virginia sweetspire (Itea virginica), Summer blooming azaleas, Sweet azalea (Rhododendron arborescens), Indigofera (Indigofera amblyantha), Oakleaf hydrangea (Hydrangea quercifolia), Big leaf hydrangea (Hydrangea macrophylla), Tree false spirea (Sorbaria arborea), European Linden (Tilia europaea), Tall stewartia (Stewartia monadelpha), Big leaf dogwood (Cornus macrophylla), Chinese chaste tree (Vitex chinensis), Golden rain tree (Koelreuteria paniculata) andJapanese hydrangea vine (Schizophragma hydrangeoides). Herbaceous plants seen in bloom include: Summer flowering roses (Rosa sp.), Clematis vines (Clematis paniculata), Spiderwort (Tradescantia sp.), Bush cinquefoil (Potentilla fruticosa), Persicaria (Persicaria polymorpha), Water lily (Nymphaea odorata), Hardy cranesbill (Geranium sp.), and Ox-eye daisy (Leucanthemum vulgare), Bee balm (Monarda didyma), Hosta (Hosta sp.), Rudbeckia (Rudbeckia fulgida) Daylilies (Hemerocallis sp.), Hostas and Astilbes (Astilbe sp.), Coneflower (Echinacea purpurea), Milkweed (Asclepias syriaca) and Yarrow (Achillea millefolium) . Adding even more color in the landscape are an assortment of annuals.

Pests/Problems: Marginal leaf scorch was observed on Japanese stewartia. Cedar-Hawthorn rust (Gymnosporangium globosum) was observed on fruits of single seed hawthorn (Crataegus monogyna). Also observed was powdery mildew on lilac and Aronia shrubs (Aronia melanocarpa). If you have infected shrubs, apply a registered fungicide. Japanese beetles were also observed causing damage on Aronia shrubs. Despite the drought some weeds are thriving in the landscape. Poison ivy is also thriving so take caution when walking or working in the woods. Remember also that ticks and mosquitoes are still very active. Take measures to protect yourself while working outdoors, especially at dawn or at dusk.

East Region (Boston)

General Conditions: We started out the month of July with normal season temperatures with highs in the mid-80s. The first week of this reporting cycle saw two rain events, a fast moving thunderstorm on the evening of the 1st and a shower on the morning of the 5th amounting to a combined 0.57 inches. Temperatures climbed to 93° F on the 6th before a cool front moved in; conditions were cloudy and cool from the afternoon of the 7th to the morning of the 11th as temperatures remained in the mid-60s during this time – a nice refresher from the heat. Over the last two weeks, high temperatures ranged from 64° F to 93° F, and low temperatures ranged from 58° F to 68° F. We gained 290 GDDs to bring us up to 1153 for the year and received only 0.72 inches of rain over the last two weeks. Over the last month, less than an inch (0.89”) of precipitation has fallen. Plants in bloom include: Aesculus parviflora (bottlebrush buckeye), Albizia julibrissin (silk tree), Aristolochia contorta (birthwort), cultivars of Caryopteris x clandonensis (bluebeard), Clematis hexapetala (clematis), Lonicera sempervirens (trumpet honeysuckle), Platycodon grandiflorus (balloon flower), Pontederia cordata (pickerelweed), Rhododendron prunifolium (plumleaf azalea), Stewartia pseudocamellia (Japanese stewartia), and Vitex negundo var. heterophylla (cut-leaved chaste tree). The harmless but overly large male cicada killers (Sphecius speciosus) have emerged and can be seen fighting for territory as they wait for the females to emerge.

Pests/Problems: Despite several rain events over the last couple of weeks, July has been below average in precipitation and moderate drought conditions persist. Many deciduous plants are showing signs of stress; concern over the lack of precipitation following a tough winter and high winter moth and gypsy moth feeding in the spring. Following the rainfall on the morning of July 5th, there was a noticeable emergence of Gypsy moth (Lymantria dispar) adults. Cedar apple rust appears to be thriving on Rosaceous plants, has been observed on hawthorn (Crataegus sp.), mountain-ash (Sorbus sp.), rose (Rosa sp.), and shadbush (Amelanchier sp.). Weeds in bloom that are just beginning to seed include: aven (Geum sp.), enchanter's nightshade (Circaea lutetiana), European black nightshade (Solanum nigrum), and common groundsel (Senecio vulgaris). Purple loosestrife (Lythrum salicaria) is flowering in moist meadow areas as is broadleaf cattail (Typha latifolia). Two-marked treehopper (Enchenopa binotata) adults are abundant on common hoptree (Ptelea trifoliata). Lacebugs remain active, every life stage can be found on susceptible plants.

Metro West (Acton)

General Conditions: One wouldn’t know if it were August or early spring by looking out into the landscape. The hot and dry temperatures and brown lawns indicate that it is August but the lack of foliage due to moth feeding on some trees indicates early spring. Once again, precipitation was pretty much non-existent during this recording period. The average monthly precipitation for July is 3.43” and recorded for the month so far has been a mere 0.36”. Woody plants seen in bloom this past week are: Aesculus parviflora (Bottlebrush Buckeye), Albizia julibrissin (pink silk tree), Buddleia spp. (Butterfly Bush), Castanea mollissima (Chinese chestnut), Hydrangea arborescens (Smooth Hydrangea), H. paniculata (Panicle Hydrangea), H. quercifolia (Oakleaf Hydrangea), Oxydendron arboreum (Sourwood), Potentilla fruiticosa (Potentilla), Rosa rugosa (Rugosa Rose), R. 'Knockout' (The Knockout family of Roses), Rosa spp. (Rose), Spirea japonica 'Alpina' (Daphne Spirea), Stewartia psuedocamellia (Japanese Stewartia), and Tilia cordata (Littleleaf Linden). Woody vines in bloom are Campsis radicans (Trumpet vine) and Clematis spp. (Clematis). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Achillea millefolium (Yarrow), Alcea rosea (Hollyhocks), Asclepias syriaca (Common Milkweed), A. tuberosa (Butterfly Weed), Astilbe spp. (False spirea), Campanula takesimana ‘Elizabeth’ (Bellflower), Cichorium intybus (Chicory), Actaea matsumurae 'White Pearl' (Bugbane), Coreopsis verticillata (Threadleaf Coreopsis), Daucus carota (Queen Anne's Lace), Echinacea purpurea (Coneflower), Filipendula sp. (Meadow Sweet), Gaillardia aristata (Indian Blanket Flower), Geranium ‘Johnson’s Blue’ (Cranesbill), Hemerocallis 'Stella D'Oro' (Daylily), H. fulva (Orange Daylily), H. spp. (Daylily), Heuchera spp. (Coral Bells), Hosta spp. (Plantain Lily), Lavendula angustifolia (Lavender), Leucanthemum sp. (Shasta Daisy), Liatris spicata (Spike Gayfeather), Lilium spp. (Lily), Lysimachia clethroides (Gooseneck Loosestrife), Monarda didyma (Bee-Balm), Oenothera macrocarpa (Ozark Sundrops), Perovskia atriplicifolia (Russian Sage), Phlox paniculata (Garden Phlox), Rudbeckia fulgida var. sullivantii 'Goldsturm' (Black-eyed Susan), Tradescantia sp. (Spiderwort), Verbena hastata (American Blue Vervain), and Yucca filamentosa (Yucca).

Pests/Problems: The lack of any rain continues to be a concern for our trees and shrubs in the landscape especially compounded with any other stresses such as winter, tent or gypsy moth caterpillars, hemlock woolly adelgid, snow and ice removal applications, or anthracnose on our plants. A drought watch for this area and for most of the central and northeastern regions in the State has been declared by the Massachusetts Office of Energy and Environmental Affairs. Recently planted trees and shrubs as well as mature trees will need supplemental watering. Signs of stress are apparent in the landscape including premature leaf drop and wilting.One of our most aggressive weeds, Cynachum nigrum (Black Swallowwort) is flowering and will be setting seed soon. Look hard for it growing in and amongst shrubs. It can be difficult to detect. Another weed just coming into bloom now is Lythrum salicaria (Purple Loosestrife) and it can be seen growing in moist areas. Most importantly, begin to scout for the Asian Longhorned beetle! Monitor the 12 host genera: Acer (Maple), Betula (Birch), Ulmus (Elm), Salix (Willow), Aesculus (Horsechestnut), Fraxinus (Ash), Platanus (Plane Tree), Populus (Poplar), Sorbus (Mountain Ash), Albizia (Mimosa), Cercidiphyllum (Katsura) and Keolreuteria (Golden Raintree) for this invasive pest. Look for oviposition sites, frass and exit holes.

Central Region (Boylston)

General Conditions: Very dry conditions have been punctuated with cooler, overcast days with sparse rainfall. Unirrigated turf is brown and roadside weeds, and unirrigated plants are showing signs of drought stress. In bloom in the landscape now are Stewartia pseudocamellia, Hydrangea quercfolia, Hydrangea paniculata ‘White Moth’, Yucca filamentosa, Hydrangea serrata ‘Bluebird’, Persicaria polymorpha, Geranium ‘Rozanne’, Nepeta ‘Walker’s Low’ and ‘Junior Walker’, Perovskia atriplicifolia, Calluna vulgaris cultivars, Hemerocallis are going full-tilt, Knautia macedonica, many Astilbe cultivars, Hosta, Lavender, Achillea millefolium cultivars, Echinacea, and many annuals, tender perennials and vegetables are coming into their own.

Pests/Problems: Persistent lack of rainfall remains our largest problem. Fire Blight strikes in apples, crabapples and related plants, including Spiraea, continue to show. Japanese Beetles are emerging and showing up on plants throughout the landscape. Asiatic Beetles are also active. We continue to see Dogwood Sawfly larvae, Imported Willow Beetles, many, many male Gypsy Moths in flight, egg masses of gypsy moths, leaf miner on swiss chard, and birch sawfly. Powdery mildew is showing on Phlox paniculata, Monarda cultivars and Peonies.

Pioneer Valley Region (Amherst)

General Conditions: The drought that has characterized the 2016 growing season continued over this past reporting period in the Pioneer Valley despite several scattered rain showers. The month of June ended with precipitation totals far below average throughout the region. Total accumulations were roughly one-third to one-half of normal averages in Greenfield (2.22″; 52% normal), Amherst (1.48″; 36% normal) and Westfield (2.41″; 53% normal). As a result of the drought, municipal water use restrictions have been enacted in select towns in Franklin, Hampshire and Hampden counties (http://www.mass.gov/eea/agencies/massdep/water/watersheds/municipal-water-use-restrictions.html). As the drought continues, more towns are likely to enact similar bans over the next several weeks. As of 7/12, nine towns in the tri-county area have either mandatory (Orange, Shelburne, Northampton, Ware, Westfield and Southwick) or voluntary (Hatfield, Belchertown and Southampton) restrictions. The restrictions vary by town, so details should be obtained from local offices. Regardless, watering via sprinklers or sprayers during the heat of the day should be eliminated, as a significant volume of the water can evaporate if the system is not calibrated correctly (frequently observed). Precipitation was recorded on nine days in the valley over this two-week reporting period. The problem, however, was that these storms were highly scattered and mostly resulted in minor accumulations, ranging from 0.05 – 0.40″. For some, any rain was welcome and something to celebrate. That’s the point we’re at in the region, feeling good about an overcast day with mild temperatures and 0.2″ of rain. Yet, for bone dry lawns and planting beds, these accumulations have done little to nothing to alleviate the mounting drought stress. According to the U.S. Drought Monitor (http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?MA), eastern portions of the valley are now categorized in the D2 (severe drought) stage. High temperatures varied widely since the beginning of July, ranging from a peak of 91° on 7/6 to a minimum of 65° on 7/9 in Northampton. Low temperatures have mostly settled back into the 50s to low 60s each night, making for pleasant sleeping weather. Dew points have crept up to uncomfortable levels at times, but for the most part it has not been a humid summer.

Pests/Problems: Lawn grasses and weeds in exposed settings are brown and crisp and many desired groundcover plants are also wilted and dead, even in somewhat shaded settings (e.g. vinca). Trees and shrubs weakened by construction damage, insect infestation and disease are showing drought stress symptoms. The dry conditions have made Dutch elm disease visible on American elms, especially trees in difficult urban settings or suffering from root compaction and/or severing. However, the majority of trees and shrubs in the landscape still appear robust despite the lack of meaningful rain. Some have even continued to flush new growth, such as members of the red oak group. Irrigated trees and shrubs appear vibrant, as the lack of rain has significantly reduced disease pressure from anthracnose fungi and stem cankering pathogens. Root and butt rot fungi that produce annual fruiting bodies are beginning to emerge. These large, overlapping shelf-like structures are usually produced at the base of infected trees or grow from lateral roots close to the main trunk. Chicken of the wood (Laetiporus cincinnatus and L. sulphureus) and Berkeley’s polypore (Bondarzewia berkeleyi) have both been observed in recent days. These fungal pathogens attack several deciduous hardwoods but are most commonly observed parasitizing oak (Quercus spp.). With the start of July marks the beginning of scarab beetle season. Oriental and Japanese beetles have emerged since our last reporting period. Populations of these perennial pests don’t appear to be as high as in previous years, based on anecdotal observations in Hampshire County. The green June bug (Cotinus nitida), a large and metallic green beetle more common in the southeast, has been observed. Females can lay up to 75 eggs, which develop into very large white grubs (up to 1.5″ long). Feeding by the grubs can seriously degrade turfgrass and garden vegetable roots. Despite the dry weather, Phyllosticta leaf blotch of witchhazel continues to cause damage. Large shrubs in shaded settings have been observed with few remaining leaves from the disease.

Berkshire Region (Great Barrington)

General Conditions: Though the recent trend toward hot weather continues, it appears that some relief for the drought is in the works as heat and humidity combine to create a pattern of stormy weather. The first event in this new pattern occurred on Saturday, July 9th, and Sunday, July 10th as a combined total of 1.96 inches of rain fell at this monitoring site in Great Barrington; less than half that was recorded in Pittsfield. As is the case with summer thunderstorms, rainfall amounts vary considerably from location to location. While the Berkshires were not included in the drought watch and drought advisory declaration by the Massachusetts Drought Management Task Force, parts of the County are quite deficient in rainfall amounts for the year. It remains to be seen how this change in weather will affect the droughty areas of the County. Lawns, landscape, and home gardens have been showing symptoms of the effects of the drought. The natural landscape appears unaffected though water levels in streams and ponds is very low. Water conservation practices should be encouraged. The county has been somewhat cooler than the rest of the state – not an unusual occurrence given the high elevations - but Tilia cordata (Littleleaf Linden) which is no longer on the Phenology list came into bloom over the past two weeks and is now in the full to end category.

Pests/Problems: Japanese beetles have made an appearance during the past week. The level of infestation varies but is rather high in some locales and in some gardens and landscapes. At present, it seems that the highest populations are in vegetable gardens and in berry patches. Asiatic garden beetle adults remain active though rarely seen during daylight hours. However, anyone weeding or otherwise digging in soil is likely to encounter this nocturnal pest.

Despite a major outbreak of gypsy moth in central and eastern parts of the state, few of the caterpillars have been seen in Berkshire County. In fact, this scout has only seen one gypsy moth caterpillar this spring and summer.

Oak leaf lace bug nymphs and adults have made an appearance. These piercing, sucking insects cause chlorosis and stippling on oak foliage, and may reduce plant vigor and cause premature leaf drop, but, for the most part, the damage is cosmetic rather than life-threatening to the tree.

Pests which continue to be active include: spruce spider mite, woolly beech aphid (infestation is dwindling), aphids (causing sooty mold on leaves of certain trees, notably tulip trees), mosquitoes, deer ticks, earwigs, wasps, and hornets. Slug and snail are present but their populations and damage have been low. Deer browsing is still an issue as is browsing by rabbits, squirrels, chipmunks, and voles; the latter population remains at a very high level and the damage they cause in gardens is a common complaint of home gardeners.

Disease pressures are a bit low, probably the result of the prolonged spell of dry weather. Powdery mildew, apple scab, cedar apple rust (fruiting bodies called aecia can be seen on the undersides of apple and crabapple leaves) and abiotic diseases, i.e. sunscald and marginal leaf scorch are among the few diseases observed. Several cankers, with symptoms suggesting Botryosphaeria canker, were found on trunk of redbud (Cercis canadensis) and is resulting in death of several branches.

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:

Dutch elm disease, caused by Ophiostoma novo-ulmi, on American elm (Ulmus americana). Tree is approximately 100-years-old and resides in an open lawn setting in full sun. Recent construction has seriously damaged the tree, injuring roughly 2/3 of the bark around the trunk at the base. Severe vascular staining was observed on submitted stems (~0.5″ in diameter). The tree may have been infected for many years but was successfully resisting the disease, until mechanical damage reduced vigor.

Tubakia leaf blotch, caused by Tubakia dryina, on red oak (Quercus rubra). This is a late season disease that is common on trees in the red and white oak groups, typically developing in July and August in our region. Symptoms can mimic anthracnose, but mostly develop as marginal blotches and spots that coalesce to consume the foliage. Trees suffering from insect defoliation damage may be especially sensitive to attack this season.

Root rot caused by Phytophthora on American cranberrybush (Viburnum trilobum 'Wentworth'). Shrub was in the ground only six weeks when leaves blackened and withered. Planted in shaded setting and watered by hand as needed. Upon arrival in the lab, the shrub was planted too deep and had numerous circling roots from the pot in which it originated. Significant root mortality was also observed from an overall large fine root mass. Phytophthora can be pervasive at woody plant nurseries, as are circling roots and buried root flares in potted plants.

Rhizosphaera needle cast of white fir (Abies concolor). Large, mature tree (approximately 30-years-old) with lower branch needle browning. The affected branches are heavily shaded by the upper canopy and surrounding trees. No known stresses have been inflicted in recent years but the site is in an area where soils are droughty.

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:

  • White Spotted Pine Sawyer (WSPS): Adults are still active and will be throughout this month, 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 emerge in Massachusetts in July and August. Beginning in this month, 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 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.
  • Gypsy Moth: Since our last landscape message, gypsy moth adults have begun to emerge in full force in areas where defoliation was particularly bad this season. Adult males (brown with black markings) are seen fluttering around, in search of the females who cannot fly, although they have wings (females are white with black markings). Reports have come in of “clouds of (male) moths” seen flying in areas around the Quabbin Reservoir and others like Uxbridge and the Warren/West Brookfield town line. Thousands of male moths have been seen flying in Hanson (see Southeast Region Report). Towns where multitudes of caterpillars were seen defoliating trees this season are seeing the adults. It is too late to manage gypsy moth this year, as the adults do not feed. However, if many egg masses are laid in your area by the adult females, it may not be a bad idea to start planning which management options you are going to choose for next spring. These options can include hoping for a wet spring, so that Entomophaga maimaiga, the insect killing fungus, will become more active earlier in gypsy moth and reduce the population next year. They can also include using Bacillus thuringiensis Kurstaki on the young caterpillars when they first hatch from their eggs next year around 90 GDD’s, base 50°F. Be advised that while this may lead to the demise of young caterpillars hatching from eggs on the host trees to which it is applied, it is not a guarantee that caterpillars “ballooning in” (using silk strands to catch air currents to disperse) from wooded areas won’t do any damage. Older caterpillars can be managed using spinosad, however treating gypsy moth early, when caterpillars are still small, is best.

    For now, monitor the adult activity and the number of egg masses that are laid. If multitudes of egg masses are present on property you wish to manage, you may consider such applications next season. Traps are for monitoring purposes only and do not effectively reduce adult populations. Areas such as 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, Topsfield, Gloucester, and Wrentham which reported elevated caterpillar activity paired with defoliation this season may see more of the same next year. Environmental factors such as rainfall amounts next spring (which impact Entomophaga spread and infection in these caterpillars) can make predicting caterpillar activity for next season difficult. For more information about gypsy moth this year, please visit: https://ag.umass.edu/news-events/highlights/gypsy-moth-outbreak-in-massachusetts-2016.

A captured male gypsy moth. The feathered antennae are fantastic for locating a female mate. (Photo credit: Tawny Simisky)     Female gypsy moths laying eggs in Amherst (Photo credit: Ken Gooch).

  • 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 adult moths are active. 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. As eggs laid by the adults hatch, larvae can be targeted with a summer rate horticultural oil spray, however timing is critical. Observe suspect plants with a hand lens or microscope for the presence of larvae before making any management decisions.
  • Asiatic Garden Beetle: Autocerica castanea adults remain 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 remain active. 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.)
  • Eastern Tent Caterpillar and Forest Tent Caterpillar: Both of these insects are finished feeding for this season and eggs have been laid. Management until next spring can include removing the rounded-edged egg masses of the eastern tent and squared-edged egg masses of the forest tent caterpillar.

Egg mass of the eastern tent caterpillar. Notice the rounded edges. (Photo credit: Tawny Simisky)

  • 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 are active. 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. The “Smokey Winged Beetle Bandit” wasp or Cerceris fumipennis adults are active. This native, ground-nesting wasp is excellent at finding buprestid beetles, or the jewel beetles, including our own native species as well as the invasive emerald ash borer. The female wasps are already busy collecting these jewel beetles and provisioning their own individual (although aggregated) subterranean nests with paralyzed beetles on which they will lay an egg. Although these wasps are not able to decrease the emerald ash borer population in the state, they can be used as a monitoring tool with a technique known as biosurveillance. These wasps nest in hard-packed, sandy soils in full sunlight, such as those found in baseball diamonds and along dirt roads. These wasps are also incapable of stinging people. They can be distinguished from other ground-nesting wasps that might offer a painful sting by their black body with a single yellow band on the abdomen and yellow spots on the head (3 on the females, 2 on the males) and their blue-black iridescent wings. The openings to their nests are about the thickness of a pencil and often have a buildup of sand in a mound around them, known as a tumulus. Sometimes jewel beetles can be found on the ground, scattered between the groups of nests. If you find these wasps nesting in a ballfield or other such area, there is no need to remove them (no one will get stung).

Female Cerceris wasp leaving her underground nest. Note the single wide yellow band on the abdomen and the blue-black iridescent wings of this non-stinging wasp that is used to monitor for emerald ash borer. (Photo credit: Tawny Simisky)     Native jewel beetles (buprestids) found near Cerceris wasp nests in Granby, MA. Beetles are sometimes dropped by these wasps. (Photo credit: Tawny Simisky)

  • Hemlock Woolly Adelgid: Adelges tsugae is present on eastern and Carolina hemlock. The adelgid has entered its summer dormant period which will last until approximately mid-October. Dormant nymphs can be treated throughout the summer with a horticultural oil spray at the summer rate, however be careful to follow all label instructions to avoid injury to the plant.
  • Introduced Pine Sawfly: Diprion similis is active. Inspect needles of plants such as mugo pine for any remaining rows of eggs embedded within the needles. Remove and destroy such needles when found. Most eggs will be hatched and tiny larvae clustering to feed. When they can be reached, young larvae can be managed with an insecticidal soap. Older larvae may require spinosad. Redheaded Pine Sawfly, Neodiprion lecontei is also active on the same hosts. This yellow-bodied caterpillar-like insect has distinct rows of black spots and a rust-colored head capsule. Feeding in clusters well into the fall, these sawflies are capable of defoliating the host. Young larvae can be treated with an insecticidal soap or a horticultural oil spray at the summer rate.
  • Lily Leaf Beetle: Larvae continue feeding. Pyrethroids can be used against adult beetles, whereas spinosad products are most effective against the larvae.
  • Rhododendron Borer: Synanthedon rhododendri clearwing moths are active. 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.
  • Taxus Mealybug: Dysmicoccus wistariae remain active. 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.
  • Two-Spotted Spider Mite: Tetranychus urticae remains active and is a “warm-season” mite that loves hot and dry weather which may favor the quick reproduction and build-up of this pest. Management should seek to preserve beneficial predatory mites. Monitor susceptible hosts (such as many deciduous species) for increasing numbers of these mites until mid-August. Mites will be found on the undersides of leaves and cause stippling of the foliage.
  • Viburnum Leaf Beetle: Adults will be emerging within the next couple of weeks and will resume feeding on the plant into September. Adult beetles may be targeted with a pyrethroid; however, adult beetles are generally more difficult to manage than the larval stages. 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).

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: Hydrangea arborescens ‘Annabelle’

Hydrangea arborescens is a native deciduous shrub growing 3-5’ tall and wide. Flowers corymbs of the species are 4-6” across and consist of non-showy fertile dull white flowers and a few showy sterile larger flowers. Cultivars such as ‘Annabelle’ and ‘Grandiflora’, offer larger, showy flowers. H. arborescens ‘Annabelle’ has large (8-12”) symmetrical, rounded white flower corymbs. Leaves are 2-6” long, dark green and toothed. Plants can bloom for up to two months. Smooth hydrangea is best grown in well-drained soils in part shade; they can tolerate full sun with consistent moisture. Plants do not deal well with drought. Harsh winters can cause plants to die back to the ground. Plants can also be pruned in late winter as they bloom on new wood, this can also help promote stem vigor and keep plants more tidy. No serious problems, but can be susceptible to bud blight, bacterial wilt, leaf spot, powdery mildew, rust, aphids, mites, scale, and nematodes. Other H. arborescens cultivars can offer pink, double, or lacecap flowers.

Hydrangea arborescens ‘Annabelle’     Hydrangea arborescens ‘Annabelle’     Hydrangea arborescens ‘Annabelle’     

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

Landscape Turf

Insects

More Dry Weather Insect Woes

And the (drought) beat goes on. We received a smattering of rain in the Amherst area earlier this week but not nearly enough to make up for all the evapotranspiration losses from the past several weeks. These dry conditions, as noted in an earlier post, make it hard to distinguish some insect activity from summer dormancy.

Be on the look-out for chinchbugs and billbugs, especially. They normally feed most aggressively in July and August, and the damage resembles drought stress. In fact, after I posted a similar comment a couple weeks ago, I received several e-mails from people, many of whom included photos of damaged areas and pictures of the guilty insects. So sadly, I was right - conditions are perfect for chinchbugs and billbugs to get established and do a lot of damage.

So again - monitor for chinchbug and billbug activity. Heavy chinchbug populations can be reduced with a pyrethroid. (If you are a golf course superintendent, remember that any application of a pyrethroid can contribute toward the development of resistance of annual bluegrass weevils to pyrethroids.) Billbugs are much more challenging to control once they reach the larval stages. Your best bet will be to manage the damage (raise the height of cut if possible, provide irrigation if possible) and make a note to take action next spring.

White grubs

Adults of all the white grub species (Japanese beetles, oriental beetles, European chafers, Asiatic garden beetles, masked chafers) have been flying for at least a couple weeks. Remember that dry conditions such as we are experiencing in unirrigated turf will force many females to delay egg laying until soil moistures increase enough for the eggs to survive. That means that we may not see new grubs hatching until a couple weeks (or more) later than usual.

Much of Massachusetts is currently 5 to 8 inches below "normal" for precipitation for the year, which translates to various levels of drought advisories. Many towns have already enacted watering bans, and the current forecast does not show much relief in sight. Keep in mind that insecticide applications that are made to target grubs really need to be watered in, but that may be really hard to do this summer. And remember that the neonicotinoids have some systemic activity, but the ability of the plant to take up the active ingredient is severely compromised when the plant is dormant.

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