Landscape Message: June 17, 2016

June 17, 2016

Issue:

UMass Extension's Landscape Message is an educational newsletter intended to inform and guide Green Industry professionals in the management of our collective landscape. Scouts compile and record environmental and phenological data for locations throughout Massachusetts to aid in the monitoring of plant and pest development, the planning of management strategies, and the creation of site-specific records for future reference. Detailed reports from Extension specialists on growing conditions, pest activity, and cultural practices for the management of woody ornamentals, trees, and turf are regular features. UMass Extension has updated the following issue to provide timely management information and the latest regional news and environmental data.

The Landscape Message will be updated weekly April through June. The next message will be available on June 24. 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 9 through June 15. Soil temperatures and phenological indicators were observed on or about June 15. 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 (1-Week Gain)	Time/Date of Readings
Region/Location	1-Week Gain	2016 Total	Sun	Shade	Precipitation (1-Week Gain)	Time/Date of Readings
Cape Cod	94	508	75	62	0.11	4:35 PM 6/15
Southeast	76	515	74	66	0.12	4:30 PM 6/15
North Shore	83	487	61	58	0.02	9:30 AM 6/15
East	86.5	581	72	66	0.05	5:00 PM 6/15
Metro West	78	532	62	58	0.04	5:45 AM 6/15
Central	69	608	70	60	0.14	4:45 PM 6/15
Pioneer Valley	77	599	66	62	0.37	9:00 AM 6/15
Berkshires	56	509	67	63	0.55	11:00 AM 6/15
AVERAGE	77	542	68	62	0.18	-
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.
Hydrangea arborescens (Smooth Hydrangea)	*	Begin	*	*	*	*	*	*
Tilia cordata (Littleleaf Linden)	Begin	*	Begin/Full	*	Begin/Full	*	Begin/Full	*
Rhus typhina (Staghorn Sumac)	*	*	Begin	*	*	*	Begin	*
Ligustrum spp. (Privet)	*	Begin	Begin	Full	Full	*	Begin/Full	Begin
Sambucus canadensis (American Elderberry)	*	*	Begin	Begin/Full	*	Begin	Begin	*
Catalpa speciosa (Northern Catalpa)	*	Begin	Full	*	Begin/ Full	*	Begin	Begin
Syringa reticulata (Japanese Tree Lilac)	Begin	Full	*	Full	Full	Full	Full	*
Philadelphus spp.(Mockorange)	Begin/Full	Full	Full/End	Full/End	Full/End	End	Full	Full
Cornus sericea (Red Osier Dogwood)	*	*	*	*	End	End	*	Full
Cotinus coggygria (Common Smokebush)	Begin/ Full	End	Full	Full	Full	Full	Full	Full/End
Kalmia latifolia (Mountain-laurel)	Full	Full	Full	Full	Full	Full	Full/End	*
Hydrangea anomala petiolaris (Climbing Hydrangea)	Full	Full	Begin	End	Full	Full/End	Full/End	Full
Robinia pseudoacacia (Black Locust)	Full/End	End	End	*	End	End	End	*
Kolkwitzia amabilis (Beautybush)	Full	Full	Full/End	End	Full/End	Full	Full/End	Full
* = no activity to report/information not available

Regional Notes

Cape Cod Region (Barnstable)

General Conditions: The weather has been a mixed bag for this reporting period. The reporting week started off on the cool side, with daytime temperatures in the low 60s and nighttime temperatures in the low 50s. The forecast included thunderstorms for Saturday the 11^th but they didn’t materialize for most of the Cape. A few cells passed over Cape Cod Bay, and the lower Cape, especially Provincetown, actually received some much needed rain. The rain gauge in Marstons Mills recorded only 0.11”. Soils are starting to be seriously dry. The weather returned to more moderate temperatures and sunshine on Monday, the 13^th and the extended forecast is for beautiful and dry weather. Baptisia cultivars are in full bloom, along with Astrantia and Siberian Iris. Early peonies have passed but later cultivars are still in bloom. Styrax japonica is in full bloom.

Pests/Problems: Plants in areas without irrigation are showing signs of wilting during the sunny, warm part of the day. Newly planted landscape plants will need to be monitored for water stress. Water well upon planting and continue to water as there is no rain in the immediate forecast.

Gypsy moth caterpillars continue to feed and get larger. Most appear to be in the 5^th instar, although some smaller ones have been observed. Holly leaf miner adults are active. Small puncture holes on the new foliage of American holly, Ilex opaca, are a result of feeding. Egg deposition into the foliage will commence soon. Pieris lacebug nymphs can be observed on the underside of leaves of Japanese Pieris, commonly called Japanese andromeda. Azalea sawfly larvae are still feeding on foliage of deciduous azaleas but will be finished soon, as will the rose slug sawfly larvae. Slugs and snails are active, along with cutworms, carpenter bees, wasps, bumblebees and honeybees. Mosquitoes are active in areas located near bogs and ponds or wherever there is standing water. Deer tick nymphs are active and dog tick adults are active.

Black spot of rose is beginning to appear on susceptible roses. Apple scab and cedar-apple rust lesions can be seen on susceptible crabapples.

Southeast Region (Hanson)

General Conditions: Warm, windy, sunny days, and some cool nights, has been the norm for the past week. Hanson received 0.12 inches of rain. Soils are very dry and plants in unirrigated landscapes are starting to wilt and flowers are prematurely going-by, due to the warm, dry weather. If Dicentra spectabilis goes without water for too long, it often dies back and goes dormant for the remainder of the season. Remind clients to water their plants, especially trees defoliated by caterpillars. The following plants are in full bloom: Liriodendron tulipifera (Tuliptree), Magnolia virginiana (Sweetbay magnolia), Styrax japonicus, Sinocalycanthus chinensis, Cornus kousa, Weston hybrid azaleas, Hydrangea anomala petiolaris, Itea virginica, Spiraea sp., Rhododendron sp., Calycanthus floridus (Common Sweetshrub), Indigofera sp., Beautybush, Weigela florida, landscape roses, Lonicera sempervirens, Rosa rugosa, Clematis sp., Viburnum dilatatum (Linden Viburnum), Viburnum dentatum (Arrowwood Viburnum),Clematis, Alchemilla mollis, Salvia sp., Geranium sp., Thalictrum aquilegifolium, Anemone canadensis, Persicaria polymorpha, Doronicum sp., Lamium, Foxgloves, Allium, Nepeta sp., Baptisia australis and Baptisia hybrids, Dianthus sp., Tradescantia, Lupines, Corydalis lutea, and Valeriana officinalis. Chionanthus virginicus, Physocarpus opulifolius (Eastern Ninebark) and Amsonia sp. are ending bloom. Cotinus obovatus (American Smoketree) and Cotinus coggygria (European Smokebush) are now past bloom and are producing plume-like hairs (that form on the sterile flowers) which provide the landscape with their colorful “smoke”. It is a banner year for Kousa dogwoods!

Pests/Problems: The “big story in town” this week is about Gypsy moth caterpillars, which are in 4^th and mostly 5^th instars. These late instar caterpillars are feeding heavily and the resulting frass or “insect poop” can be heard falling in those areas where caterpillar populations are high. In some areas the caterpillars have done a good job defoliating oak and apple trees that were spared by winter moth caterpillars. There are reports of heavy feeding in areas of Carver, Plymouth, Kingston, Middleboro, etc. There are also reports of a very few “sick” and dying caterpillars but not enough to make a difference. We really need rain for soil moisture for plants and also to activate the fungus, Entomophaga maimaiga. (See Tawny Simisky’s report in the Insect Section of the Landscape message).

Asiatic garden beetles have started to emerge. These small copper-colored beetles feed at night on a wide range of plant material and are often attracted to lights. Caterpillars of the sunflower moth, (Homoeosoma electellum), were found in flowers and flower buds of Bidens ferulifolia. Sunflower moths lay eggs on the developing flower buds of plants in the Compositae (Asteraceae) family. The eggs hatch into small, brownish-dark grey caterpillars which destroy the buds and flowers, making them appear ‘rain-damaged’ and messy. Besides Bidens, monitor other composite plants like Echinacea, Helianthus,Rudbeckia, Heliopsis and marigolds. Earwigs are now active, as are slugs and snails, all of which are often found feeding on plant material at night. Feeding by the roseslug sawfly larvae has ended.

Continue to monitor dogwoods for dogwood sawfly which is active and manage if needed.

Continue to monitor for Andromeda lacebug on Japanese andromeda (Pieris japonica) and managed as needed. This can be a serious pest of Pieris, especially when planted in sunny locations. Euonymus caterpillars have started to pupate. The following insects remain active: White pine sawyer beetle (Asian longhorned beetle lookalike), Hemlock woolly adelgid, woolly beech aphid, cottony camellia scale on Meserve hollies and Taxus, Taxus mealybug, mosquitoes, aphids, stink bugs, four-lined plant bugs, leafhoppers, lily leaf beetle, wasps, pine spittlebugs, azalea whitefly, hornets, deer flies, horse flies, dog ticks and deer tick nymphs. Sod webworm moths remain active on turf. With all the dry weather here in southeast, MA, not too much has shown up plant disease-wise: a few leaf spots on dogwood; some tip dieback on Kwanzan cherry, most likely caused by brown rot (Monilinia sp.) and leaf spot showing up on a Hydrangea quercifolia ‘Little Honey’, which is probably receiving too much sun and stressing the plant. Continue to remove Azalea leaf galls (Exobasidium vaccinii) from deciduous azaleas and place them in the trash. White pine pollen is done for the year, having left behind a ‘blanket’ of yellow ‘dust’ covering the landscape. A good rain is also needed to wash that away! It is a banner year for chipmunks and rabbits, with many people commenting about the damage they do.

North Shore Region (Beverly)

General Conditions: The weather during this reporting period was fairly cool for this time of the year. We had very nice days with mainly sunny or partially sunny skies. Day temperatures were in the low to mid 70s and the night temperatures were mainly in the low 50s. We gained 83 growing degree days at Long Hill during this reporting period, it was also quite dry. At Long Hill we recorded only 0.02 inches of rainfall during this period. Woody plants seen in bloom include: Chinese dogwood (Cornus kousa), Arrowwood viburnum (Viburnum dentatum), Chinese Neillia (Neillia sinensis), Magician Deutzia (Deutzia magicien), Fringe tree (Chionanthus virginicus), Mock orange (Philadelphus spp.), Beautybush (Kolkwitzia amabilis), Betty Layman azalea (Rhododendron ‘Betty Layman’), Mountain Laurel (Kalmia latifolia), Weigela (Weigela florida), Mapleleaf viburnum (Viburnum acerifolium), Tulip tree (Liriodendron tulipifera), Korean dogwood (Cornus coreana), Stewartia (Stewartia rostrata), Chinese stewartia (Stewartia serrata), American holly (Ilex opaca), Japanese snowbell (Styrax japonica), and Bigleaf Magnolia (Magnolia macrophylla). Non-woody plants seen in bloom include: Bush Cinquefoil (Potentilla fruticosa), Foam flower (Tiarella cordifolia), Fetterbush (Leucothoe fontanesiana), Scotch rose (Rosa spinosissima), Peony (Paeonia sp.), Cranesbill (Geranium sp.), Bleeding heart (Dicentra spectabilis), Redleaf rose (Rosa glauca), Rodger's flower (Rodgersia aesculifolia), Goat’s beard (Aruncus dioicus), Japanese primrose (Primula japonica), Water lily (Nymphaea odorata), Columbine (Aquilegia spp.), Sweet woodruff (Galium odoratum), and annuals such as petunia and million bells.

Pests/Problems: Phyllosticta leaf blotch was observed on Witchhazel (Hamamelis intermedia). Woolly beech aphid (Phyllaphis fagi) continued to be observed on European beech (Fagus sylvatica). Cedar quince rust (Gymnosporangium clavipes) continued to be observed on twigs of Eastern red cedar trees (Juniperus virginiana). Unpruned galls of azalea leaf and flower gall (Exobasidium vaccinii) are now white with spores. Prune them off and discard as soon as possible. Multiflora rose (is in full bloom on roadsides and borders of properties. Some other weeds in bloom include Spiderwort (Tradescantia sp.) and Bindweed (Convolvulus arvensis). Ticks and mosquitoes are still active.

East Region (Boston)

General Conditions: Temperatures have been cooler than normal, high temperatures averaged 72° F, ranging from 67° F to 78° F; lows have been very consistent, ranging from 50° F to 56° F, averaging 52° F for the week. Precipitation has been minimal with only 0.05 inches falling during a one-hour rain event on the afternoon of the 11^th. Conditions have been windy this week resulting in a number of downed branches and damage to newly planted trees. Many plants are in bloom and include: Clematis spp. (clematis), Lonicera sempervirens (coral honeysuckle), Ilex glabra (inkberry), Philadelphus coronarius (sweet mock orange), Physocarpus opulifolius (common ninebark), Potentilla fruticosa (shrubby cinquefoil), many roses and their hybrids including Rosa rugosa (beach rose), R. ‘Dorothy Perkins’, R. ‘Carefree Beauty’, R. ‘Julia Childs’, R. ‘Seafoam’, and R. ‘Zephirine Drouhin’, Spiraea japonica (Japanese meadowsweet), and Tripterygium wilfordii (thunder god vine). Herbaceous material in flower: Allium giganteum (giant onion), A. schoenoprasum (chives), Amsonia hubrichtii (Arkansas blue star), Clematis recta 'Purpurea' (ground virginsbower), Coreopsis sp. (tickseed), Delphinium spp. (larkspur), Digitalis purpurea (common foxglove), many cultivars of Heuchera spp. (coral bells), Lupinus spp. (lupine), Nepeta spp. (ornamental catmint), Oenothera spp. (evening primrose), Papaver orientale (Oriental poppy), Salvia spp. (Salvia), and Veronica spp. (speedwell).

Pests/Problems: The perennial weeds horsenettle (Solanum carolinense) and yellow nutsedge (Cyperus esculentus) have emerged. Curly dock (Rumex crispus), goutweed (Aegopodium podagraria), and poison hemlock (Conium maculatum) are in flower. American pokeweed (Phytolacca americana) seedlings are germinating. Aphids remain abundant throughout the landscape; ladybird beetles can be found in all stages actively feeding on aphid populations. Leafminer damage is visible on hawthorn (Craetagus sp.) and crabapple (Malus sp.).

Metro West (Acton)

General Conditions: This past week’s temperatures have cooled down some with morning temperatures recorded as low as 44° F on the 11^th and the 12^th. Typical high temps for the week were recorded in the mid 70’s. While winds were relentless all week, precipitation was pretty much non-existent. Woody plants seen in bloom this past week are Catalpa speciosa (Northern Catalpa), Chionanthus retusus (Chinese Fringe Tree), C. virginicus (Fringe Tree), Cotinus coggygria (Common Smokebush), Kalmia latifolia (Mountain Laurel), Kolkwitzia amabilis (Beautybush), Ligustrum spp. (Privet), Philadelphus coronarius (Sweet Mock Orange), Physocarpus opulifolius (Common Ninebark), P. opulifolius 'Summer Wine'(Summer Wine Ninebark), Potentilla fruiticosa (Potentilla), Rosa rugosa (Rugosa Rose), R. 'Knockout' (The Knockout family of Roses), Rosa spp. (Rose), and Spirea japonica 'Alpina' (Daphne Spirea). Woody vines in bloom are: Clematis spp. (Clematis) and Lonicera sempirvirens (Trumpet Honeysuckle). Contributing even more color and interest to the landscape are some flowering herbaceous plants including: Achillea millefolium (Yarrow), Alchemilla mollis (Lady's Mantle), Allium giganteum (Giant Onion), A. schoenoprasum (Chives), Amsonia hubrichtii (Arkansas Blue Star), Aruncus aethusifolius (Dwarf Goat’s Beard), A. dioicus (Goat’s Beard), Campanula persicifolia (Peach-leafed Bell Flower), Campanula takesimana ‘Elizabeth’ (Bellflower), Centaurea montana (Cornflower), Chrysogonum virginianum (Green and Gold), Clematis recta 'Purpurea' (Clematis), Coreopsis sp. (Tickseed), Dianthus deltoides (Maiden Pink), Digitalis purpurea (Foxglove), Filipendula sp. (Meadow Sweet), Geranium cantabrigiense 'Biokovo' and 'Cambridge' (Hardy Cranesbill), G. macrorrhizum (Bigroot Geranium), G. sanguineum (Cranesbill Geranium), Hemerocallis 'Stella D'Oro' (Daylily) and H. spp. (early blooming Daylily), Heuchera spp. (Coral Bells), Hosta spp. (Plantain Lily), Leucanthemum sp. (Shasta Daisy), Lupinus 'Russell Woodfield Hybrids' (Lupine), Nepeta spp. (Ornamental Catmint), Oenothera macrocarpa (Ozark Sundrops), Paeonia spp. (Peony), Papaver orientale (Poppy), Penstemon digitalis 'Husker Red' (Beardtongue), 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: Pine Sawyer Beetles have recently emerged and are very often confused with the Asian Longhorned Beetle but can be distinguished by its single white dot found at the base of its wing cover. Rosa multiflora continues to bloom and is very easy to detect because of its prolific white flowers and can be seen growing in and amongst other trees and shrubs. Also observed in the landscape this past week were Gypsy moth caterpillars and wooly beech aphid.

Central Region (Boylston)

General Conditions: The weather for this past week has been relatively cool, dry, and punctuated by a couple of days with very gusty winds. We are irrigating turf, beds and borders and all recent transplants. Among the many things in bloom are Peonies, Salvia ‘Blue Hill’, Penstemon ‘Prairie Dusk’, Penstemon pinifolius, Rhododendron ‘Chionoides’, Viburnum dilatatum cultivars, Dianthus ‘Firewitch’, Geranium ‘Rozanne’, Persicaria polymorpha, Astilbe cvs., Sinocalycanthus raulstonii ‘Hartlage Wine’, Knautia macedonica, Baptisia australis, Styrax japonicus, Magnolia sieboldii, Zenobia pulverulenta, Magnolia virginiana, Callirhoe involucrata, and Cornus kousa cultivars.

Pests/Problems: A great deal of damage (particularly to oaks) from gypsy moth caterpillars can be seen throughout the region. Adult Lily-leaf beetles are active, White Spotted Sawyer Beetles, often mistaken for Asian Longhorned Beetles, are out and about. The damage from Viburnum Beetle and Imported Willow Leaf Beetle larvae is evident on our native viburnums, and on many willows. Rust is showing up on Hollyhocks.

Pioneer Valley Region (Amherst)

General Conditions: Below-average temperatures and high winds were abundant this past reporting period in the Pioneer Valley. Much of this past week was spent in the upper 60s to mid-70s and low temperatures mostly hovered in the mid-40s. However, with the gusty winds it felt much cooler at times. Ambient air temperatures dipped into the upper 30s in Franklin County and the hill towns during the early hours of Friday 6/10. At Barnes Airport in Westfield, sustained winds of 30 mph and gusts up to 41 mph were recorded on Sunday 6/12. Wind speeds decreased on 6/13 and 6/14 but were still prominent throughout the valley. The long-term forecast calls for a return to more seasonable temperatures, with highs in the 80s and maybe even 90s by early next week. We had a single rain event during this reporting period, a northwest to southeast tracking system that moved through the western Massachusetts on Saturday 6/11. Accumulations were varied in the valley with up to 0.5″ recorded in Easthampton and Springfield. However, Ashfield, Greenfield and Belchertown saw significantly less. The most significant accumulations appeared to fall in western Hampden County and southern Berkshire County. The cool nights have reduced soil temperatures slightly, back towards the middle 60s in full sun and lower 60s in the shade. Turfgrass seems to have responded well to the cooler temperatures, losing some of the brown that was developing in full sun areas. More rain would be welcome but we’ve received just enough since the beginning of June to stave off any symptoms of drought stress. Overall, we’re still in the “sweet spot” of the season where most plants are green, lush and mostly free of disease, insect and environmental stress issues.

Pests/Problems: The UMass Cold Spring Orchard reports spotty occurrence of fire blight in the region. The mostly dry, cool weather has not been conducive to disease development and there have been no positive samples submitted to the diagnostic lab this season. Horsechestnut leaf blotch, caused by the fungal pathogen Guignardia, is just starting to develop. Trees on the UMass campus are exhibiting pale green, angular-shaped, water-soaked blotches between primary veins. The blotches will expand over the course of the season and become brown-colored and the leaf tissue is killed. Horsechestnuts look great early in the season and gradually appear tattered and worn as the summer progresses. The wood-decaying pathogen Kretzschmaria has been actively growing over the past several weeks. This fungus is primarily found on sugar maple and beech and is most conspicuous on large, landscape European beech. Old fruiting bodies appear black and crustose and can be found on patches of dead bark, mostly near the soil line. Current season’s fruiting bodies are grey in color with white margins and appear flattened against the bark. Infections by Kretzschmaria can lead to bleeding cankers, a symptom most often associated with infections by Phytophthora. This is one of many reasons why symptoms alone should not be used to make a positive identification. Scattered white pines continue to shed needles produce in 2015 and 2014, leaving only the current season’s growth at the shoot tips. The strong winds and rain this month have flushed most of the dead needles away, leaving branches and entire trees looking very thin. Foliar anthracnose is becoming more problematic in recent weeks on sugar, red and Japanese maple.

Berkshire Region (Great Barrington)

General Conditions: The past week has been much colder than normal, more like April rather than mid-June. Night time temperatures through the week ranged from the low to high 40s. Likewise, day time temperatures were below normal, mostly in the low 60s. That pattern broke on June 15, though the morning reading at this site was 48° F at 6:00 AM. By early afternoon, temperatures reached into the low 80s. This warming trend is expected to continue. Continuous high winds were also an issue through the past week, making it feel much colder than the actual temperature. Though I did not see any fallen trees resulting from the winds, there were plenty of twigs and branches strewn about. Late Saturday, June 11, brought the only significant rain for the week. Non-cultivated soils are moderately moist. Cultivated soils and coarse soils tend to be dry. Rainfall for the year is about 3.5 inches below normal. The dominant flower in unmanaged landscapes at present is Multiflora rose (Rosa multiflora). Though showy and fragrant, it is a well-known invasive species which displaces many native shrubs and herbaceous plants. While on the subject of flowering plants, black locust (Robinia pseudoacacia) and yellowwood (Cladrastis) are the latest species of several plants on this season’s phenology list to be devoid of flowers or to have sparse flowering. None of the black locust observed on scouting treks in south Berkshire County have produced any flowers. Black locust was also very slow to leaf out this year. The -20° F temperature of February and single digit temperatures in April have taken their toll on many plants species.

Pests/Problems: One pest which has prompted lots of attention lately is the hydrangea leaf-tier (Olethreutes ferriferana). The adult leaf-tier is a small brown moth that lays eggs on the branches of hydrangea in fall or spring. The eggs hatch into small light green caterpillars which sew together two terminal leaves with silk-like threads to create and envelope. The caterpillars feed on the leaves and enclosed flower buds for about 10 days before pupating. Usually the damage is minimal and control, other than squashing the caterpillar by pinching the leaves, is not warranted. Leaf galls, especially those related to eryiophyid mites, are also attracting much attention. The galls vary in form, depending upon host and mites species, from spindle, bladder, and globular shapes to felt-like patches on leaves. Most often, these galls cause no economic damage to the host plant. Ongoing pests/problems include: aphids, leaf rollers, spruce spider mite, woolly beech aphid, spittlebug, boxwood leaf miner (adult stage), cutworms, slugs, snails, mosquitoes, deer ticks (nymph stage), wasps, voles, and chipmunks. Eggs of oak leaf lace bug that were observed last week on leaves of bur oak have not yet hatched. Perhaps the chilly temperatures have delayed egg hatching. Spots of cedar apple rust and apple scab continue to enlarge. Powdery mildew continues to spread on foliage of Physocarpus opulifolius ‘Coppertina’. Weir’s cushion rust (Chrysomyxa weirii) – also called spruce needle rust - seen earlier this spring on old needles of spruce is now infecting needles of new growth. This particular rust has no alternate host.

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

A special report from the UMass Extension Plant Diagnostic Lab on management recommendations for Eastern white pine with symptoms of canopy decline:

Management recommendations for Eastern white pine with symptoms of canopy decline

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:

Gypsy Moth: Caterpillars are actively feeding on the leaves of hosts including oak (mostly), maple, birch, poplar, willow, etc. 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. In certain areas, where elevated gypsy moth caterpillar populations have fed heavily on oak, there have been reports of this caterpillar feeding on pine this week (ex. Hanson). 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, and Winchendon are reporting continued and elevated caterpillar activity. Caterpillars have been observed to be in the 4^th and some in the 5^th instar. The heaviest feeding from this insect will occur over the next week or so, with caterpillars growing ever larger until pupation begins in late June and early July. Adult emergence will occur primarily in July when 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.
Andromeda Lacebug: Stephanitis takeyaiis active on Japanese Andromeda. 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.
Arborvitae Leafminer: Argyresthia thuiella is pupating now and small, silvery-tan moths will be active soon. 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.
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 will be active soon. 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.) Treat with a pyrethroid insecticide, if necessary, to prevent re-infestation.
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.
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.
Euonymus Caterpillar: Yponomeuta cagnagella is pupating. Now that this insect has reached this stage, it is too late for chemical management.
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.
Roseslugs: Two species of sawfly can be found on the leaves of roses. These small, caterpillar-like larvae will skeletonize the upper leaf surface and leave a “window-pane” like pattern behind. When present in large numbers, these insects are capable of defoliating their entire host. Management options include an insecticidal soap spray or a product containing spinosad.
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 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 can be active when temperatures are above freezing 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: Cornus kousa

Cornus kousa is a small to medium sized tree growing 20-30’ tall and wide. The bracts are the showy part of the infloresence, similar to Cornus florida. The 4 creamy white bracts emerge in June after leaf emergence, in contrast to Florida dogwood which blooms 2-3 weeks earlier and before leaf emergence. The fruit is a red drupe on a 2-2.5” long pendulous stalk. The globular fruits somewhat resemble a raspberry and can be quite showy. Another ornamental feature is the mottled gray-tan-brown bark that becomes more exfoliating with age. Leaves are dark green in the summer changing to red or reddish purple in the fall. Best in a well-drained, acidic to neutral soil in full sun to part shade. Cornus kousa has better disease resistance and cold hardiness than C. florida. If plants are situated in full sun leaf scorch can be a problem if soil is dry. Cultivars offer various flower sizes as well as pink bracts.

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

Massachusetts Pollinator Week

In Honor of MA Pollinator Week – From MDAR’s Farm and Market Report: Governor Baker will declare the week of June 20^thMA Pollinator Week. Government officials will visit and learn more about the state apiary. The declaration recognizes the impacts of pollinators on agriculture and encourages the public’s support of pollinators. The kick-off is on Monday June 20 at 10 am, and the event is open to the public. Contact: Julia.Grimaldi@state.ma.us.

Tips for Protecting Pollinators While Celebrating MA Pollinator Week!

There are two types of pollination, self-pollination in which a plant is able to pollinate itself without outside help, and cross-pollination which is pollination aided by animals, wind, and water. The majority of pollination is cross-pollination with animal assisted pollination accounting for around 75% of the total. Pollination is necessary for fruit development, seed production, and can result in better quality of some fruits (such as tomato). According to the United States Department of Agriculture (USDA), pollinators are responsible for 1 out of every 3 bites of food you eat.

Rapid and dramatic decline of European honeybee populations have been reported by bee-keepers over the last several years. Researchers are trying to determine the likely causes of this phenomenon, referred to as honeybee decline or colony collapse disorder. Current theories on the decline of honeybees include a combination of factors such as parasites, disease, low genetic diversity, poor nutrition, loss of habitat, management stress, and pesticide use.

Along with managed European honeybee populations, many native insects act as pollinators in Massachusetts. These include various species of ants, bees, wasps, beetles, butterflies, moths, flies, and true bugs (Order: Hemiptera). While managing pest insects on landscape, nursery, and urban plantings, applicators have a responsibility to do so while causing the least possible harm to pollinators and other non-target and beneficial insects.

Best Management Practices for Pollinators when Using Chemical Management:

Do not treat crops or plants in bloom
Use the least toxic pesticide. In addition to neonicotinoid pesticides, many other pesticides may also be harmful to bees, including pesticides used for organic production. Different formulations of pesticides also vary significantly in their toxicity to bees. Dusts are much more hazardous than sprays, and wettable powders usually provide a significantly longer hazard than emulsifiable concentrates because the dry particles cling better to the body hair of foraging bees.
Adjust pesticide applications in relation to weather conditions. Honey bees can become active and forage at temperatures as low as 55° F. If temperatures following treatment are unusually low, residues on the crop may remain toxic to bees up to twenty times as long as following normal temperatures. Conversely, if abnormally high temperatures occur during late evening or early morning, bees may forage actively on the treated crops during these times.
Apply pesticides when bees are not actively foraging or visiting plants. Many insecticides can be applied in late evening, night, or early morning with relative safety to bees. This timing is typically from 6:00 PM to 7:00 AM in Massachusetts.
Become familiar with state regulations concerning the protection of pollinators. In Massachusetts there are additional requirements for notifying apiaries if a bee toxic pesticide is being applied to blooming fruit trees or blooming field crops (alfalfa, clover, and trefoil). The specific requirements are listed in 333 CMR 13.07(2) of the Massachusetts Pesticide Regulations.
Know where bee colonies are in your area. Bees forage up to several miles searching out concentrations of flowers, plants shedding pollen and/or producing nectar. Contact beekeepers if you intend to make a pesticide application that may kill bees. Cooperation between beekeepers and pesticide applicators is essential to reduce bee kills from pesticides. Contact your area or county beekeeper association to learn if beekeepers are maintaining hives in your area.
Do not place unmarked honeybee colonies adjacent to fields or orchards, which are likely to be treated. Beekeepers should put their name, address, and phone number or approved identification number on hives.

For more information about pollinators in the landscape, visit:

Adapted from Mandy Bayer, UMass Extension Landscape, Nursery, & Urban Forestry Program and Tina Smith, UMass Extension Greenhouse Crops and Floriculture Program

Garden Retailers

Garden Retailers – Time to Feed Your Plants

Garden retailers are reminded that annual flowering plants waiting for sale may need to be fertilized. Rainfall and watering with plain water will leach out nutrients and plants will exhibit deficiency symptoms such as yellow or reddish foliage. If no additional fertilizers are applied, plant quality will quickly deteriorate especially plants that will not be transplanted, such as hanging baskets. Plants in packs, 4-inch and other small containers are also susceptible to nutrient deficiency. The little soil volume in the smaller containers allows the nutrients to quickly leach from the container.

Depending on the plants and container size, options include using a water soluble fertilizer or topdressing with a controlled- release fertilizer according to directions (if it was not applied by the grower prior to shipping). Retailers should communicate with their wholesale suppliers about controlled-release fertilizer or look for fertilizer prills in planters.

Before fertilizing, check hanging baskets and mixed planters for controlled release fertilizer (CRF) prills. Squeeze a few to see if the prills are depleted. If you find mostly empty prills, or if prills were washed out, another application of CRF may be needed. A good option for mixed planters and hanging baskets is to topdress with controlled-release fertilizer according to the label when the plants are sold.

If water soluble fertilizers are used, ideally, plants should be fertilized with every irrigation using a fertilizer injector. For retailers who don't have a fertilizer injector, an inexpensive "Hozon" proportioner can be used. A Hozon is a much better option than lawn and garden injectors which are designed for home gardeners. A Hozon has a ratio of about 1:16; 1 gallon of fertilizer stock will make 16 gallons of fertilizer solution. The goal is to maintain plant quality, not to promote growth. Therefore, the optimum fertilization regime should include a neutral fertilizer (e.g. 17-4-17) at a low rate (between 50 to 100 ppm N) with low phosphorus (P). The purpose is to maintain the pH and electrical conductivity (EC) of the growing media and feed the plants with enough nutrients to prevent nutrient deficiencies. Fertilizing with every watering may not be an option if staff and/or injectors are limited. In that case, a higher fertilization rate (150-200 ppm N) may be used once a week. Maintaining fertility levels in the sales area will extend the life of plants in small containers and the period of time the flowering basket looks good for the consumer.

Report by Tina Smith, UMass Extension Floriculture Program

Additional Resources

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For home gardeners and garden retailers - Check out home lawn and garden resources. UMass Extension also has a Twitter feed that provides timely, daily gardening tips, sunrise and sunset times to home gardeners, see https://twitter.com/UMassGardenClip

Diagnostic Services

A UMass Laboratory Diagnoses Landscape and Turf Problems - The UMass Extension Plant Diagnostic Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other green industry professionals. It provides woody plant and turf disease analysis, woody plant and turf insect identification, turfgrass identification, weed identification, and offers a report of pest management strategies that are research based, economically sound and environmentally appropriate for the situation. Accurate diagnosis for a turf or landscape problem can often eliminate or reduce the need for pesticide use. For sampling procedures, detailed submission instructions and a list of fees, see Plant Diagnostics Laboratory

Soil and Plant Nutrient Testing - The University of Massachusetts Soil and Plant Nutrient Testing Laboratory is located on the campus of The University of Massachusetts at Amherst. Testing services are available to all. The function of the Soil and Plant Nutrient Testing Laboratory is to provide test results and recommendations that lead to the wise and economical use of soils and soil amendments. For complete information, visit the UMass Soil and Plant Nutrient Testing Laboratory web site. Alternatively, call the lab at (413) 545-2311.

Ticks are active at this time! Remember to take appropriate precautions when working and playing outdoors, and conduct daily tick checks. UMass tests ticks for the presence of Lyme disease and other disease pathogens. Learn more

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