UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
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UMass Extension Landscape Message #8 2013
May 10, 2013
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-June. The next message will be available on
May 17. 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
Regional Notes
Cape Cod
Southeast
East
Metro West
Central
Pioneer Valley
Berkshire
Environmental Data
Phenology
Scouting Information by Region
Woody Ornamentals
Regional Notes
Landscape Turf
Cape Cod Region (Barnstable):
Reader Feedback
General Conditions: Dry is the word to describe the Cape this reporting period. Add to that brisk breezes
and it is no surprise that newly planted material is in need of water. Much needed rain fell overnight May 8–9,
but overall The Cape is running a deficit. The chilly temperatures of last week have turned into nice, mild
temperatures, averaging in the low to mid-60s F during the day and the upper 40s F to low 50s F for
overnight. It is still too early to plant tender annuals and tomatoes but hardy perennials and nursery stock can
all go in at this time as long as they are watered in well. Early daffodils and tulips are almost done while late
daffodils and mid-season tulips are coming into bloom. Epimedium and primrose are blooming and brightening
the May garden. Mayflower viburnum is perfuming the landscape. Pests/Problems: Winter moth caterpillars
are webbing together foliage of apple and roses and other tender foliage. Small feeding damage is visible but
the population at least in the Marstons Mills area, appears to be down from previous years. Spinosad sprays
can be applied to expanding foliage. Lily leaf beetle adults are out and feeding and mating. Hand pick and
destroy the adult beetles and monitor the bottom of the foliage for eggs, which can be rubbed out. Slugs and
snails are active and rabbits are grazing. Woodchucks are also out and eating tender vegetation.
Southeast Region (Hanson):
General Conditions: Over the past two weeks, Hanson has received no rain, although rain is predicted
beginning today (May 8 th ) and supposedly into the weekend. Let’s hope so. Soils are powdery and
supplemental watering for newly planted trees, shrubs, lawns, etc, is still recommended. This has been a
beautiful spring with extended color and rain at this time would hopefully help to continue extending the spring
color. The bright yellow-green flowers of our native Sassafras albidum continue to bloom. Late blooming
magnolias like the beautiful ‘Coral Lake’ and ‘Elizabeth’, along with Kwanzan cherry, Crabapples, Cornus florida
(Flowering dogwood), Cercis canadensis (Eastern Redbud), Cercis chinensis (Chinese redbud), Viburnum
carlesii (Mayflower Viburnum), Viburnum x burkwoodii ‘Mohawk’, Rhododendron schlippenbachii (Royal Azalea),
http://extension.umass.edu/landscape/message/lm-8-2013[5/13/2013 12:21:06 PM]
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Urban & Community Forestry
Archived Messages
UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
Rhododendron carolinianum, Prunus serotina (Black Cherry), Exochorda (Pearlbush), Spiraea prunifolia
(Bridalwreath Spirea), Spiraea thunbergii ‘Ogon’, Pieris japonica, Pieris floribunda (Mountain Pieris), Fothergilla
major (large Fothergilla), Fothergilla gardenii (dwarf Fothergilla), Flowering Almond, Kerria, Daphne tangutica,
Rhododendron ‘Olga Mezitt’, Epimedium sp., Mazus repens, Trillium sp., Tulips, late blooming Narcissus,
Polygonatum sp. (Solomon's Seal), Euphorbia polychroma, Brunnera macrophylla, Asarum canadense,
Stylophorum diphyllum (Wood Poppy), Tiarella sp., Phlox subulata, Phlox divaricata, Galium odoratum (Sweet
Woodruff), Arisaema sp. (Jack-in-the-pulpit), Corydalis lutea, Corydalis scouleri, Primula sp., Euphorbia
polychroma, Pulmonaria sp., Ajuga, dwarf bearded Iris, Saruma henryi, Lamiastrum galeobdolon, Lamium sp.,
Lunaria annua (honesty or money plant), Tiarella cordifolia (Foam Flower), Mertensia virginica (Virginia
bluebells), Violets and Vinca minor are in full bloom. Lilac, Convallaria majalis (Lily-of-the-valley) and Phlox
stolonifera are beginning to bloom. Glaucidium palmatum, Helleborus x hybridus and H. foetidus are ending
bloom. Hosta has leafed out and is providing nice foliage color (and also dinner for deers!). Hummingbirds
returned May 8th! Pests/Problems: Winter moth caterpillars are in second and third instar and according to
anecdotal reports and field observations, numbers appear down, however, continue to monitor host plants:
American and European beech, maples (Norway, sugar, paperbark, red and Japanese, etc.), roses, oaks, birch,
crabapples, apples, etc) and manage if needed. There aren’t too many to be seen, but Eastern tent caterpillar
webs are expanding and they can be easily removed and destroyed at dusk when the caterpillars retreat back
to their tents. Ants are active in lawns and around patios, etc. Wasps and hornets have started to appear, as
well as mosquitoes. Lily leaf beetle adults are active and eggs were found on lily foliage. Willow leaf beetle,
carpenter bees, honey bees, boxwood psyllid, snowball aphids, mason bees, Hemlock woolly adelgid, black
flies, deer and dog ticks continue to be active. May is traditionally the month when deer tick nymphs become
active. The deer tick nymph stage is the stage often responsible for transmitting Lyme disease as the ticks are
very tiny, hard to detect, and are active for several months. To minimize being bitten and possibly contacting
Lyme disease or other tick-borne diseases: consider using a repellent, conduct tick checks frequently, shower
or bathe after yard work and place clothes in the dryer to desiccate and kill any ticks. Beneficial insects are
also active. Barberry, one of the many Massachusetts invasive plants, is in full bloom and other invasive
plants like autumn olive, burning bush and oriental bittersweet will soon be blooming. To reduce seed
production, prune or remove the plants now. Garlic mustard, ground ivy, buttercups, veronica, violets,
chickweed, wild mustard, and dandelions are in full bloom. The new, shiny reddish-green growth of poison ivy
has emerged and is easily visible. Deer are browsing hosta and other favorite plants and rabbits are also
browsing. Wild turkeys continue to roam neighborhoods and are often found in the vicinity of bird feeders.
East Region (Boston):
General Conditions: We have not received any precipitation so far in the month of May. We have received
12.01 inches of precipitation (rain and snow equivalence), of which almost 7 inches fell in February, so far this
year compared to the historical average of 15.67 inches at this point in the year. Precipitation is predicted over
the next few days. We have had a variety of daytime highs ranging from 52 º F to 77º F and lows of 37º F to
45º F. We are at 96.5 GDDs having gained 20.5 GDDs over the past 7 days, 8 GDDs coming on May 2 nd and
11 GDDs coming on May 7 th . Despite the dry soil conditions, the landscape is lush and colorful.
Rhododendrons, crabapple, flowering dogwood and lilacs are adding much color. Continuing to put on quite the
show are: Chamaedaphne calyculata ‘Verdant’ (leatherleaf), Exochorda x macrantha ‘The Bride’ (pearlbush),
Fothergilla sp. (fothergilla), and Rhododendron vaseyi (pinkshell azalea). Herbaceous plants in flower include:
Arisaema sp. (Jack-in-the-pulpit), Hyacinthoides hispanica (Spanish bluebell), Phlox subulata (moss phlox),
Trillium erectum (red trillium), and Uvularia grandiflora (large bellwort). The vine flower show has begun with
Akebia quinata (fiveleaf akebia), Clematis alpina ‘Blue Dancer’ (alpine clematis), Clematis alpina ‘Helsingborg’
(alpine clematis) and Wisteria sinensis (Chinese wisteria) leading the way. Newly flowering this week are:
Elaeagnus multiflora (cherry elaeagnus), Enkianthus campanulatus (redvein enkianthus), Halesia tetraptera
(Carolina silverbell), Halesia tetraptera var. monticola (mountain silverbell), Paeonia rockii (Rock's peony),
Poncirus trifoliata (trifoliate orange), Rhododendron kaempheri (torch azalea), Vaccinium sp. (blueberry), and
Weigela subsessilis (weigela). The rare and often sought after Davidia involucrata (dove tree) has started to
bloom; it is well worth the trip to see this unique tree in flower. Pests/Problems: Dry soil conditions are a
concern for recently transplanted trees and shrubs. Turf growing in well drained areas is showing signs of
drought stress. Lack of precipitation does not seem to be affecting invasive weeds. Japanese knotweed ranges
in height from one to four feet. Garlic mustard (Alliaria petiolata) is thriving and in full bloom and preparing to
set seed. Greater celandine (Chelidonium majus) continues to grow and is just coming into bloom. Pokeweed
(Phytolacca americana) has emerged and is starting to become visible throughout the landscape. In terms of
insects, winter moth caterpillars continue to feed and grow. Hydrangea leaf tier (Olethreutes ferriferana) has
hatched and the caterpillars have formed their visible safe haven around the upper leaves and flowers at the
tips of the stems of Hydrangea arborescens (smooth hydrangea) and its cultivars. Pollen in the air is mostly
from oak, maple and birch as these trees continue to flower.
Metro West (Acton):
General Conditions: There was no gain in precipitation but there was a gain of 12.5 GDD this past week.
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UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
Woody plants seen in bloom this past week are Amelanchier spp. (Shadbush, Serviceberry), Cercis
canadensis (Redbud), Chaenomeles speciosa (Common Flowering Quince), Cornus
florida (Dogwood), Daphne x burkwoodii ‘Carol Mackie’ (Daphne), Forsythia spp. (Forsythia), Fothergilla
gardenii (Dwarf Fothergilla), F. major (Large Fothergilla), Halesia tetraptera (Mountain Silverbell), Magnolia
‘Butterflies’ (Magnolia Butterflies), M. ‘Yellow Lantern (Yellow Lantern Magnolia), Malus spp. (Apple,
Crabapple), Pieris japonica (Japanese Pieris), Prunus spp. (Cherry), Prunus serotina (Black Cherry), P.
japonica (Flowering Almond), Pyrus spp. (Pear), Rhododendron mucronulatum (Korean Rhododendron), R. 'P.
J. M.' , Spiraea thunbergii (Thunberg Spirea), Syringa vulgaris (Common Lilac), Vaccinium angustifolium
(Lowbush Blueberry), V. corymbosum (Highbush Blueberry), Viburnum x burkwoodii (Burkwood Viburnum)
and V. x burkwoodii ‘Mohawk’ (Mohawk Burkwood Viburnum). Buds on plenty more woody plants are swelling
and ready to burst but meanwhile contributing even more color and interest to the landscape are some
flowering herbaceous plants and spring ephemerals including: Ajuga reptans (Bugleweed), Arisaema
triphyllum (Jack-in-the-Pulpit), Aurinia saxatilis (Basket of Gold), Bergenia cordifolia (Pig Squeak), Caltha
palustris (Marsh Marigold), Claytonia virginica (Virginia Spring Beauty), Dicentra canadensis (Squirrel Corn), D.
cucullaria (Dutchman’s Breeches), D. spectabilis (Old Fashioned Bleeding Heart), D. spectabilis ‘Alba’ (White
Flowering Old Fashioned Bleeding Heart), Epimedium x versicolor ’Roseum’ (Pink Flowering Barrenwort),
E. x versicolor ‘Niveum’ (White Flowering Barrenwort), E. x versicolor ‘Sulphureum’ (Yellow Flowering
Barrenwort), Erythronium rostratum (Yellow Troutlily), Helleborous niger (Christmas Rose), Hyacinthus spp.
(Hyacinth), Iberis sepervirens (Evergreen Candytuft), Iris germanica (Bearded Iris), Linaria annua (Money
Plant), Mertensia virginica (Virginia Bluebells), Muscari sp. (Grape Hyacinth), Myosotis sylvatica (Forget-menot), Narcissus spp. (Daffodil), Nepeta spp. (Ornamental Catmint), Omphalodes cappadocica (Navelwort),
Pachysandra terminalis (Japanese Pachysandra), Phlox subulata (Moss Phlox), Polygonatum spp. (Solomon's
Seal), Primula spp. (Primrose), Stylophorum diphyllum (Wood Poppy), Tiarella cordifolia (Foam
Flower), Trillium erectum (Red Flowering Trillium), T. grandiflorum (White Trillium), T. luteum (Yellow
Wakerobin), T. sessile (Toadshade Trillum), Tulipa spp. (Tulip), Uvularia sessilifolia (Bellflower), Vinca
minor (Periwinkle), Viola spp. (Violet), Waldsteinia ternata (Barren Strawberry) and Zizia aptera (Heart-Leaved
Alexander). Pests/Problems: There was no rain fall recorded this past week so lack of any rainfall continues
to be a major concern. Snowball Aphid is evident on Viburnums and caterpillars are actively feeding on the
foliage of Malus (Crabapple) and Prunus (Cherry). Ticks, mosquitoes and black flies are feeding and active.
Alliaria petiolata (Garlic Mustard) is in full bloom as is Berberis thunbergii ( Barberry). Both of these plants are
highly invasive. Other weeds seen in bloom now are Glechoma hederacea (Ground Ivy), Lamium
purpureum (Purple Dead Nettle) and Taraxacum officinale (Dandelion). Emerging everywhere, in abandoned
lots, along the road side and along streams and wet areas are other nasty weeds: Arctium minus (Lesser
Burdock), Impatiens capensis (Touch-me-not) and Polygonum cuspidatum (Japanese Knotweed). Be aware
of Toxicodendron radicans (Poison Ivy). It is beginning to leaf out so it is fairly easy to detect its shiny red
leaves of three.
Central Region (Boylston):
General Conditions: The weather has been lovely but dry over the past week. Rain is in sight – trace
amounts fell today and more is on the way. Turf and shallow rooted perennials in well-drained soils are
showing signs of stress. On a positive note, the cool evening and warm days have allowed a long and
overlapping bulb season. Many of the early blooming Narcissus cultivars are finishing while the mid- and late
season cultivars are still in full bloom. The very early ephemerals (Corydalis solida, Adonis amurensis) are
finishing but Hellebores, Dicentra spectabile, Dicentra eximia, Mertensia virginica, Sauruma henryi, Primila
seiboldii, Trillium grandiflorum, Trillium erectum, Phlox subulata, Muscaria armeniacum, and Glaucidium
palmatum are all in full bloom and will soon be accompanied by Phlox stolonifera, Lady’s Slipper (Cypripedium
sp.) Peony japonica, Actaea rubra and many more. Numerous flowering trees and shrubs (Viburnum carlesii,
V. carlcephalum, Fothergilla gardenia, Vaccinium angustifolium, Pieris floribunda, P. japonica, and Syringa
vulgaris) are also coming in to bloom. Pests/Problems: Same problems of deer damage, and ticks persist.
Add black flies and a few mosquitoes.
Pioneer Valley Region (Amherst):
General Conditions: After another week of sunny, mild weather with no measurable precipitation, drought
conditions have officially set in across much of the state. According to the U.S. Drought Monitor, nearly 70%
of Massachusetts (and all of the valley) is experiencing “abnormally dry” conditions, the lowest of the five
levels of possible drought conditions (http://www.nrcc.cornell.edu/page_drought.htm l ; as of 04/30/13).
Surface soil is very dry, yet at depths of five inches or more the soil remains somewhat moist, based on
anecdotal observations. However, rain is forecasted in the valley for the next several days, but that will likely
not be enough to ameliorate the current dry conditions after nearly a month of only minimal precipitation. But,
things could be worse, as at this time last year approximately one third of the state was experiencing “severe”
drought conditions based on the U.S. Drought Monitor. Pests/Problems: Black fly and mosquito populations
remain relatively low due to the lack of rain. Yet, despite the dry weather many pathogens are now emerging
from landscape trees and shrubs. It appears that the recent dry conditions have suppressed most anthracnose
fungi, especially on sugar maple which are almost fully leafed out at this point. Oaks are beginning to leaf out
http://extension.umass.edu/landscape/message/lm-8-2013[5/13/2013 12:21:06 PM]
UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
and will be susceptible to infection with the wet conditions expected over the next several days.
Berkshire Region (Great Barrington):
General Conditions: Late April and early May have been spectacular in terms of personal comfort and
beauty in the landscape. Yet, it has been very dry and soil moisture levels remain low. As of May 8, total
year-to-date rainfall for Berkshire County remains at less than 8 inches. While rain events are predicted for
the next 5 days (May 8–May 12), these are expected to be mostly in the form of widely scattered showers.
Therefore, total rainfall may not be very much. Weeds seem not to have taken notice of the dry conditions.
Home lawns are adorned with a profusion of brightly colored flora, otherwise known as dandelions. Garlic
mustard (Alliaria petiolata) is now in bloom and plants should be pulled up, cut to ground level, or killed with
an herbicide such as glyphosate before they set seed. A single plant of garlic mustard can produce thousands
of seeds. The plant is an aggressive competitor of many native woodland wildflowers. Pests/Problems:
Active plant infesting insects now include: willow leaf beetle adults, spruce spider mite, Eastern tent caterpillar
(larvae are ½ inch long), and snowball aphids . Boxwood leaf miners are now in the pupae stage. The
orange-colored pupae can be seen by separating the upper and lower leaf surfaces of miner infested boxwood
leaves. Adult flies of Boxwood Leaf Miner should be emerging at around 300 GDD. One method of control is to
prune and destroy boxwood foliage before adults emerge. Other insects observed include carpenter bees,
yellow jackets, paper wasps, and mosquitoes. Adult deer ticks remain abundant. News media attention to the
emergence of a large population of periodical cicadas has many residents concerned and green industry
professionals in Berkshire County are getting many questions. Despite to alarming press reports, the cicadas
are not expected to be a problem in this area. More information on the periodical cicada is available at:
http://extension.umass.edu/landscape/fact-sheets/periodical-cicada
Environmental Data
The following growing-degree-day (GDD) and precipitation data was collected for an approximately one week
period, May 2 through May 8. Soil temperature and phenological indicators were observed on or about May
8. Total accumulated GDDs represent the heating units above a 50° F baseline temperature collected via our
instruments for the 2013 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.
2013 GROWING DEGREE DAYS
Soil Temp (°F at 4"
depth)
Precipitation (1-Week
Gain)
130
60°
0.90"
38
132
66°
0.00"
East
20.5
96.5
63°
0.00"
Metro West
12.5
63
62°
0.00"
Central
(Boylston)
37
105
52°
trace
Central
(Leicester)
25
93
65°
0.24"
Pioneer Valley
50
120
65°
0.00"
Berkshires
58
123
59°
0.00"
AVERAGE
36
108
62°
0.14"
Region/Location
1-Week
Gain
Total accumulation for
2013
Cape Cod
45
Southeast
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, b/full, full, f/end, end)
PLANT NAME
(Botanic/Common)
CAPE
SOUTH
EAST
EAST
http://extension.umass.edu/landscape/message/lm-8-2013[5/13/2013 12:21:06 PM]
METRO
W.
CENT.
P.V.
BERK.
UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
Syringa vulgaris (Common Lilac)
*
begin
begin
begin
begin
*
begin
Rhododendron spp. (Early
Azaleas)
begin
full
begin
*
full/end
begin/full
begin
Cornus florida (Flowering
Dogwood)
begin
full
begin/full
begin
full
begin/full
begin
Malus spp. (Crabapple)
begin
full
begin/full begin/full begin/full begin/full begin/full
Cercis canadensis (Redbud)
begin
full
full
Amelanchier spp. (Shadbush,
Serviceberry)
full
full
full/end
full/end
end
full
full
Pyrus calleryana (Callery Pear)
full
end
full
full
full
*
full
Chaenomeles speciosa
(Common Floweringquince)
full
full/end
full
full
full
full
full
Prunus serrulata (Japanese
Flowering Cherry)
full/end
full/end
end
end
full
full/end
full
Rhododendron 'P. J. M.'
full/end
full/end
end
full
full
full
full
Magnolia soulangiana (Saucer
Magnolia)
end
end
end
end
full/end
full/end
full
Forsythia x intermedia (Border
Forsythia)
full/end
full/end
end
end
full/end
full/end
full
begin/full begin/full begin/full
full
* = no activity to report/information not available
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.
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 (Boylston)- Joann Vieira, Superintendent of Horticulture, reporting from the Tower
Hill Botanic Garden, Boylston.
CENTRAL REGION (Leicester) - Mary Owen, Extension Educator UMass Extension, reporting from
Leicester.
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
Insects
The drought continues with nurseries and landscapes being in need of water. The potential for scattered
showers in some parts of the state on 5/8 and 5/9 may provide limited but temporary relief.
Winter Moth - Population numbers appear to be on the low side for much of the coastal areas in MA. Damage
thus far is minimal. Larger population numbers are higher in the Harpswell, ME population. Early scouting
there suggests an average number of 8 caterpillars per bud as reported by the Elkinton lab here at UMass.
Numbers may be higher on Cape Cod than they are in Southeastern MA this year. Fine silken webbing can be
now found on many maple species, which is typical for winter moth once the caterpillars have become settled
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UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
on a host plant. Oaks, birch, crabapple, apple, blueberry and roses are also among the common host plants for
this insect here in MA. The caterpillars are still rather small in physical size and close inspection is required
when monitoring. Any insecticide that contains Spinosad works well. Bacillus thuringiensis Kurstaki (B.t.K.)
also works well but must be ingested by the young caterpillar in order to be effective. Leaves that are not yet
fully expanded but treated with a spray of B.t.K. will quickly continue to produce more leaf tissue daily that is
not covered by the spray and therefore allowing caterpillars to potentially consume more foliage before
ingesting the bacterium. Many pyrethroid insecticides are also labeled for this pest but tend to be harsher on
foraging pollinators, such as bees, and other beneficial insects and predatory mites. Monitor host plants now
and treat where necessary. The Elkinton lab has begun their annual releases of the parasitic fly Cyzenis
albicans in MA, Maine, and Rhode Island already for this year.
Fall Cankerworm eggs have hatched. Currently, there are no known outbreak areas of this pest within the
state but small pockets of this pest may exist. This pest shares many of the same host plants with winter moth
(oaks, maples, crabapples, etc.) but the differences between these two inchworm species can be readily
distinguished by the numbers of pairs of prolegs (fleshy abdominal legs) that each of these species posses;
winter moth caterpillars having just two pairs while fall cankerworm is said to have ‘2 ½ pairs’ with the first
pair being about half as large as the other two pairs. Once active in large numbers, this pest can be managed
easily with any insecticide that contains Spinosad as the active ingredient. Many pyrethroids are also available.
Eastern Tent Caterpillar is active, primarily on apple, crabapple and cherry trees. Cotoneaster is an
occasional host. Numbers are typically low across the state this year. This native insect makes its silken web
in the crotches of branches and ventures out on warmer and sunnier days to surround and feed on expanding
foliage, Treatments are the same as for winter moth, if necessary.
Forest Tent Caterpillar will be hatching very soon. There are no known large areas of outbreak for this pest
at this time in MA but it is not uncommon for small isolated populations to occur and require management.
Treatments are the same as for the other Lepidoptera (moth larvae) described above.
Gypsy Moth caterpillars are active but still small. There are currently no known outbreak areas of this insect
in the state but occasionally small pockets of this insect can erupt and be problematic. Treatments are the
same as with winter moth. Overall, the now naturally occurring entomopathogenic (insect killing) fungus
‘Entomophaga maimaiga’ has been keeping this once serious pest in very low numbers in Massachusetts for
the past 20 years. However, atypically dry springs (such as this year, thus far) can inhibit the activity of this
fungus and allow the gypsy moth to surge in numbers during any given year. Oaks are the primary host for
this pest but many other deciduous host plants may be utilized by this insect.
Lily Leaf Beetle adults are active, mating and (as reported by Deborah Swanson in Plymouth County) have
begun laying eggs on the undersides of Asiatic lily foliage. This bright red beetle is quite obvious at this time.
In small plantings, one can monitor every 1-2 days and hand-remove adult beetles. Sprays for the adult
beetles usually require a chemical such as one of the pyrethroids, if deemed necessary. Eggs are deposited on
the undersides of Asiatic lily foliage in short irregular tan-colored lines. The eggs turn a very deep red prior to
hatching. Monitor for adults and eggs now and remove and destroy by hand if possible Larvae, when active,
are easily treated with a product that contains Spinosad.
Viburnum Leaf Beetle larvae continue to emerge from their over-wintering eggs that have been embedded
within the last 8-10 inches of terminal shoots on the host plants. Larvae are tiny and initially cause damage
to newly emerging foliage by scraping the surface thus creating tiny spots that may give the appearance of a
fungal pathogen. However, closer inspection will reveal the numerous yet tiny yellow larvae with black spots.
Treat larvae early with a product that contains Spinosad as the active ingredient. This pest is capable of
completely defoliating plants within 4-5 weeks of feeding. Adult beetles start to emerge around mid-July and
can defoliate the same host plant for a second time within the growing season. For a list of susceptible and
resistant viburnum species, visit the following web site: http://www.hort.cornell.edu/vlb/suscept.html
Hemlock Woolly Adelgid (HWA) remains very active at this time. The tiny nymphs are settled and feeding.
VT has reported that winter mortality of HWA reached as high as 45% in some parts of the state this past
winter. In MA, the Elkinton lab reports approximately a 30-40% mortality overall for the state. The small
white cottony masses that we associate with the presence of this insect are still very noticeable. Inspect now,
especially the branch undersides, for what appears like tiny white cotton balls lined up at the base of the
needles along the stems, especially out near the terminal ends of branches. Horticultural oils can be used to
kill all life stages of this pest when the correct weather conditions prevail. We are now too far into spring for
dormant oil sprays. Oil sprays at the summer rate should be used with great caution or not at all at this time
while tender new leaf growth is occurring. Systemic imidacloprid can be applied where it is not feasible to
apply oil sprays but there is a lag time between application and translocation to the growing points where this
insect feeds; usually from weeks to months depending on the size of the plant and application method (soil
applied, trunk injected, basal trunk spray, etc). Also, it is still too early for applications of imidacloprid as a
soil or trunk-injection application.
Balsam Twig Aphid is active. The stem mothers (the ‘mothers of all aphids’ are now feeding and producing
large numbers of offspring. It is the young of this aphid that feeds heavily on the newly expanding needles
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causing stunting and curling of the new needles that is often stuck together with copious amounts of sticky
honeydew. Balsam and Frasier fir are the two most common host plants for this pest here in New England. Oil
sprays at the summer rate, when weather permits before bud-break, can be effective. Many pyrethroids are
also labeled for this pest and can be applied now or soon after the offspring become active. This pest is
capable of causing much aesthetic damage to Christmas trees to the point of rendering them un-saleable
come harvest time.
Snowball Aphid is now quite apparent on many viburnum (e.g. of susceptible viburnum: Korean spicebush,
maple leaf viburnums, cranberry bush viburnum, others). The eggs of this insect have been embedded within
the shoots since last May. They have now hatched and the piercing-sucking feeding of this aphid on the newly
expanding foliage has caused leaf curling; and in some cases, severe curling. No yellowing or leaf loss occurs;
just leaf distortion. Specimen plants or plants for sale may lose aesthetic value (and perhaps sale value). The
health of the affected plant is not harmed. Management is not possible at this time. The aphids will feed
within the curled foliage through much of May and once eggs are embedded, this pest will cease to be active
for this year. The curled foliage protects the aphids from contact insecticides, such as insecticidal soap and
horticultural oil sprays. Certain systemic insecticides applied later in the growing season may over-winter
within the shoots and buds and provide protection next spring once the aphids begin feeding. It is too late for
systemic insecticides this year.
Boxwood Psyllid is active and cupped new foliage is obvious at this time. Like the snowball aphid, this
insect causes aesthetic injury and occasionally it can be severe thus rendering nursery and garden center
plants un-saleable. Treatments now will not undo the damage but can help to reduce population numbers for
the next year.
Hemlock Eriophyid Mite remains active. This tiny, peg-shaped mite is just barely visible to the naked eye.
They feed openly ( by the dozens) on the upper and lower needle surfaces of hemlock, primarily Eastern
(Canada) hemlock. Plants affected by this pest last year may already have a pale yellowish green color now.
Those being heavily attacked this year will develop that color if this mite feeding is not curtailed. Oil sprays at
the summer rate are usually quite effective. Hemlock experiences bud-break later than many other plants
here making summer rate oil sprays possible when temperatures and weather conditions permit.
Spruce Spider Mite is active. This is a cool-season mite species and is active from now until the weather
becomes quite warm (usually by late June), goes dormant during the hottest time of the year and then returns
in late-August to early September to feed and reproduce again well into the late autumn. Spruce, firs,
hemlock, and arborvitae are common hosts here. Yellow stippling (feeding injury) often begins at the base of
the older needles first and only later spills over onto the newest foliage should population numbers become
high. Oil sprays at the summer rate can be effective when weather and plant phenology permit.
Ticks remain very active. Ticks are continuing to seek hosts for a blood meal. During spring clean-up efforts
or any outside activity in tick habitat areas be aware of their presence and follow all precautions.
http://ag.umass.edu/services/tick-borne-disease-diagnostics
http://www.umass.edu/lmz/partner/top_ten_things.html
Inkberry Leafminer is maturing within the leaf mines and will be pupating soon. Infested leaves do not
display browning (usually out near the leaf tips) until later in the winter and such discoloration is often
associated with winter injury. Near the end of May, a yellow sticky card can be clipped to a branch on an
infested plant to time an application of insecticidal spray for the emerging adult flies in order to break the
cycle of re-infestation.
Emerald Ash Borer (EAB): No new information about the population in Dalton, MA (found late August 2012),
has been reported but survey work has resumed. All of Berkshire County (MA) remains a Regulated Area and
the movement of ash trees, ash tree products, and all hardwood firewood species is prohibited from this area.
The state of New Hampshire reported on April 7, 2013 that they have identified at least one tree in Concord,
NH that has been positively identified as being infested with EAB; this is a first find for the state of New
Hampshire and regulations will eventually follow.
http://www.sentinelsource.com/news/local/invasive-emerald-ash-borer-found-in-newhampshire/article_87156059-bafc-5b14-82f8-f58404b6909a.html
http://www.emeraldashborer.org
Report by Robert Childs, Extension Entomologist, Stockbridge School of Agriculture, UMass, Amherst
Diseases
Recent woody ornamental diseases of interest seen in the UMass Extension Plant Diagnostic Laboratory:
Dothistroma needle blight of eastern white pine (Pinus strobus). The pathogen, Mycosphaerella pini, is
closely related to the pathogen causing brown needle spot of white pine, which has been abundant over the
past several years in New England. Dothistroma needle blight is a widespread pathogen of pine in western
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North America, but its presence was formally documented in New England in the middle 1990s. The tree is
approximately 14-years-old, growing in full sun in soils with good drainage. Affected needles had blighted tips
that appear dark orange to red, with the necrosis progressing towards the needle base.
Snowball aphid on viburnum (Viburnum ). Young plants (<2 years) in a nursery setting with cupped foliage
and patchy chlorosis. The aphids were clustered on the underside of the leaves near the petiole and caused
noticeable stunting. The infestation was close to 100% on dozens of plants.
Diplodia blight (Sphaeropsis sapinea) on Swiss stone pine (Pinus cembra). Submitted stems were heavily
cankered and the pathogen was found fruiting extensively via small, eruptive pads of fungal tissue. While
Diplodia blight preferentially attackes two- and three-needle pines, five-needle pines are also a common host
in this region.
Volutella blight of pachysandra and boxwood. Both plantings are well-established, present at each site for
10 years and had symptoms of stem and foliar blight. The salmon-colored spore masses produced by Volutella
were clearly visible on the boxwood sample and usually occur on the underside of dead leaves.
Needle cast of Douglas-fir (Pseudotsuga menziesii) caused by Rhizosphaera. Needle blight was first
evident at the tips and progressed towards the needle base. The spore-bearing structures were abundant,
even on green needles that didn’t show any obvious symptoms of infection.
Stem blight of birch (Betula sp.) caused by Phomopsis. Approximately 10-year-old tree that was suffering
from a bronze birch borer infestation. The stress and/or wounds created by the insect likely facilitated infection
by Phomopsis, which was attacking the stem tips and progressing downward to larger stems.
Report by Nick Brazee, Plant Pathologist, UMass Extension Plant Diagnostic Lab, UMass, Amherst.
Weeds
Treat winter annual and perennial weeds in ornamental beds with glyphosate (Roundup Pro TM or equivalent)
and glufosinate (FinaleTM ). These applications are easier if done now before woody ornamentals leaf-out. The
new growth of herbaceous perennial ornamentals can be very susceptible to spray drift, so exercise extreme
caution. Non-chemical products containing clove oil, citric acid, acetic acid or orange extract can be used on
small winter annuals but not on large winter annuals or perennials. Remember these organic/non-chemical
products do not translocate and will not control established perennial weeds but will control young winter
annual weeds. Many winter annuals are just beginning to flower and have not set seed and should be
controlled now.
Common landscape winter annual weeds being observed now are:
mouse-ear cress (Arabidopsis thaliana)
thymeleaf sandwort (Arenaria serpyllifolia)
downy brome (Bromus tectorum)
shepherd's-purse (Capsella bursa-pastoris)
bittercress (Cardamine hirsuta)
sticky chickweed (Cerastium viscosum)
horseweed (Conyza canadensis)
spring whitlowgrass (Draba verna)
henbit (Lamium amplexicaule)
red deadnettle (Lamium purpureum)
field pepperweed (Lepidium campestre)
Virginia pepperweed (Lepidium virginicum)
pineappleweed (Matricaria matricariodes)
annual bluegrass (Poa annua)
knawel (Scleranthus annuus)
common chickweed (Stellaria media)
field pennycress (Thlaspi arvense)
corn speedwell (Veronica arvensis)
purslane speedwell (Veronica peregrina)
New growth expansion of poison ivy continues. Still a little early to treat, wait until the end of June to treat.
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Treat garlic mustard (Alliaria petiolata) now. Applications at this time of year will control second year plants
before they go to seed as well as first year seedlings. Look for seedlings at this time, as these seedlings will
be next years flowering plants.
Landscape mulch should be the first defense against weeds in landscape beds. Mulching can be done now at
the beginning of the season before summer annual weeds germinate. Freshly mulched landscape beds will not
require a preemergence herbicide application because the fresh mulch should supply adequate weed control in
the short term. Preemergence herbicide application should be considered on mulched areas that have not
been freshly mulched or a bit later in the season. Preemergence herbicides should be applied on top of
landscape mulches not underneath them. Compost is not recommended as a mulching material.
Report by Randall Prostak, Weed Specialist, UMass Extension Agriculture & Landscape Program, Amherst.
Landscape Turf
Insects
Neonicotinoids and bees
A disturbing trend observed the last several years is the rapid and dramatic decline of honeybee populations.
While most enjoy honey and are familiar with beekeeping as a hobby, it may be less well known that healthy
honeybees along with various native bee species are an essential part of agricultural production. Bees are
responsible for the pollination of a wide range of agricultural crops each growing season; crops valued in the
billions of dollars that are critical to the stability of our food system.
Public and private interests are currently scrambling to identify the mechanics of this pressing issue, commonly
referred to as honeybee decline or colony collapse disorder (CCD). It is important to note that commercial
honeybee colonies are affected along with wild, native pollinator populations. Current theories on the honeybee
decline phenomenon point to a factor or combination of factors among parasites, disease, low genetic
diversity, poor nutrition, loss of habitat, management stress and pesticide use. The current state of honeybee
health has been detailed in a joint comprehensive report recently released by the USDA and EPA:
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UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
http://www.usda.gov/wps/portal/usda/usdahome?contentid=2013/05/0086.xml&contentidonly=true
Concerning the role of pesticides, neonicotionoid insecticides such as imidacloprid, clothianidin and
thiamethoxam have been implicated as a potential contributing factor to honeybee decline. Neonicotinoids at
present are used widely throughout the world in both agricultural and horticultural settings because they are
effective, convenient, and much less toxic to vertebrates than older materials. Neonicotinoids are labeled for
control of a range of insects, but the most common use pattern in turf care is as preventive materials for the
control of white grubs (applications targeting grubs are typically made between mid-June and late July in the
Northeast).
Regardless of any possible role of neonicotinoids in honeybee decline, every applicator has a continual
obligation to apply all pesticides in a responsible, informed, and careful manner. The most fundamental aspects
of Integrated Pest Management (IPM) involve the reduction of pesticide use to the lowest possible level, and
minimizing the impact of applied pesticides to non-target organisms and the greater environment. Best
management practices for reducing neonicotinoid contact with bees essentially parallel the guidelines for
responsible IPM. Preventive white grub control is on the minds of many turf managers at this time of year.
When considering a decision to use preventive control for white grubs, ask yourself the following questions:
Do I need preventive control for grubs? Other than employing good fundamentals to grow healthy and
stress-resistant turf, there are no specific cultural practices that reliably lessen injury from white grubs.
Therefore, preventive grub control insecticides (applied before damage occurs) are commonly used in
situations where user expectations will not permit turf damage from white grub feeding or associated damage
from foraging animals or birds. A preventive approach is usually preferable to the most effective curative
(applied after damage occurs) insecticide, trichlorfon, which is a more mobile material with higher toxicity to
vertebrates. Trichlorfon also cannot be applied on school grounds in Massachusetts, thus preventive
applications are the only option for turf managers in such areas.
Best practices, however, dictate that preventive grub control should be used only if certain conditions are met.
Preventive control only makes sense when a certain tolerance threshold for grub damage exists, and there is
‘probable cause’ to believe that grub populations may exceed the threshold within the current season. Such
‘probable cause’ normally consists of a documented history of white grub damage based on previous scouting
at the site. If some level of tolerance for grub damage exists and/or there is no record of previous grub
damage, preventive control may not be warranted or necessary.
Do I need ‘blanket’ applications? Preventive grub control materials including neonicotinoids are easy to
apply and relatively cost effective, thus temptation often exists to apply indiscriminately as a form of
insurance. Preventive materials, however, should only be applied to specific areas that have a documented
history of damaging populations. For example, if a residence has a history of grub damage to the back yard
but no record of damage in the front, then the preventive material should only be applied to the back yard.
This saves budget, time and labor resources while at the same time reducing unnecessary application and
possible adverse impact to non-target organisms and the environment.
Am I using the correct approach? Timing is a critical consideration when using a preventive approach for
white grub control. Neonicotinoid insecticides have little or no effect against the large, mature grubs that are
present in the spring or the fall. The appropriate preventive use pattern is to time the application so that the
material is in place when the grubs are in the most susceptible stage of development, which is immediately
after egg hatch. The life cycles of the various grub species found in New England are relatively similar: adults
fly in early summer and lay eggs in late June to late July; larvae feed on turf roots from early July through
mid-autumn and again in the spring; pupae are present in the soil for a week in mid-June to mid-July; and
adults emerge early the following summer to complete the cycle. Neonicotinoids for grub control, therefore,
must only be applied within the period from approximately mid-June to early August in most years.
Applications at other times will be markedly less effective against grubs, while still carrying the potential to
affect non-target insects like bees.
Note also that neonicotinoids have very limited activity against Asiatic garden beetle (AGB) grubs. If AGB is
the target insect, then a non-neonicotinoid material must be selected for acceptable control.
How can I minimize potential bee impact when applying? Best practices for application involve
techniques to minimize exposure of foraging bees to direct application or application residue. Do not apply
neonicotinoids to turf when commonly associated forage plants, such as clover, are in bloom. This might mean
applying either earlier or later in the preventive window for grubs, depending upon prevailing conditions. Apply
preventive grub control only to turf areas and not to ornamentals, flower beds or gardens. Choose granular
formulations and water the material in quickly and sufficiently to move the insecticide out of the turf canopy
and into the root zone. If using liquid formulations, spray under calm conditions to reduce the potential for
drift. Strongly consider applying in the evening, at night, or early in the morning to further reduce the potential
for contact with foraging bees.
Are there alternatives to neonicotinoids for preventive grub control? Chlorantraniliprole (AceleprynTM
for commercial applicators, GrubEx TM for homeowners) is a non-neonicotinoid insecticide that is extremely
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effective against all white grub species (as well as caterpillars) and has no activity against bees, ants, or
wasps. The product also has a very low level of vertebrate toxicity, so much so that a signal word is not
required on the label, not even ‘Caution’. An important aspect of using chlorantraniliprole is to account for the
fact that it takes 60 to 90 days to fully dissipate in the soil for optimum effectiveness against grubs.
Therefore, the preventive window is earlier than for the neonicotinoids, usually mid-April to early June in most
years.
Paenibacillus popilliae ('milky spore') and various strains of entomopathogenic nematodes are labeled for white
grub control and have no known impact against bees. Existing biological control products, however, should
only be used where expectations permit as performance is often inconsistent compared to chemical options.
Current biologicals also vary considerably in terms of their availability, cost and effectiveness against specific
white grub species.
Report by Jason Lanier, Extension Educator, UMass Extension Agriculture and Landscape Program, Amherst
Other Relevant News / Pest Alerts
Pesticide Applicators: UMass Extension offers two-day training workshops to help pesticide applicators
prepare for Massachusetts Pesticide Applicator License Exams. For further details on licensing requirements,
exam schedules, and training workshop information, visit http://www.umass.edu/pested or call the UMass
Extension Pesticide Education Program at 413-545-1044.
Mass Aggie Seminars: The Mass Aggie Seminars is a workshop series intended for homeowners and smallscale farmers. The 2013 schedule is underway, visit http://extension.umass.edu/fruitadvisor/mass-aggieseminars for complete information.
Reader Feedback
What are you seeing? We invite you to share your current landscape observations below. Please refrain
from submitting questions or requests for information in this space. Comments are subject to moderator
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Comments
Lily Leaf Beetles
Submitted by Dianne P on Fri, 05/10/2013 - 12:54
In Groveland, MA, I have been picking off adult beetles since the first of May.
reply
Lily Leaf Beetles
Submitted by Claire on Fri, 05/10/2013 - 17:07
I've only seen one adult beetle so far this year in Plymouth, MA even though my lilies are about a foot high.
This is pretty much the same as last year. In the past I've had serious infestations which I controlled with
imidacloprid, but I haven't used any systemics for several years.
reply
winter moth
Submitted by George Markarian on Fri, 05/10/2013 - 18:12
Caterpillers are still VERY small as of 5/9 in the Westwood area.
reply
Lily leaf beetles
Submitted by Jean W on Sun, 05/12/2013 - 19:38
Yes, I have noticed the damage and have been hand-picking them since around the 1st of May. The
younger, thinner Asiatics have not been affected yet but the older, fuller Asiatics have been infested.
reply
Lily Leaf Beetles
Submitted by Suzanne C on Sun, 05/12/2013 - 20:14
http://extension.umass.edu/landscape/message/lm-8-2013[5/13/2013 12:21:06 PM]
UMass Extension Landscape Message #8 - 2013 | UMass Amherst Landscape, Nursery & Urban Forestry Program
In Cummaquid, MA, found adult beetles starting April 29th.
reply
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Lab is available to serve commercial landscape contractors, turf managers, arborists, nurseries and other
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identification, turfgrass identification, weed identification, and offers a report of pest management strategies
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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 Problem Diagnostics
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function of the Soil and Plant Tissue 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
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(413) 545-2311.
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