UMass
Extension Landscape Message #17
June 26, 2008
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The
LANDSCAPE MESSAGE is an educational newsletter intended
to guide landscape, nursery and urban forestry professionals
in identifying pests in the landscape, monitoring their
development, planning management strategies and creating
site-specific records for future management reference.
UMass
Extension has updated this issue to provide timely pest
management information and the latest regional news and
environmental data throughout Massachusetts. During the
months of July, August, and September this newsletter
will be updated bi-weekly. The next update will be available
on July 10, 2008.
Missed
a previous message? Visit the Landscape
Message Archive.
Interested
in additional turf-oriented content? UMass
Extension Turf Program Management Updates  |
SCOUTING
INFORMATION BY REGION
REGIONAL
NOTES
-
Cape
Cod Region (Barnstable) – General
Conditions: Nice summer weather has occurred over most
of the past week, with the humidity rising on Sunday, June 22. Pop-up
afternoon thunderstorms provided some much needed rain on Monday,
June 23. Early summer perennials are coming into bloom. Kousa
dogwood is especially lovely at this time. Pests/Problems: Crawlers
of cottony taxus scale are active on holly and Taxus. Slugs
and snails are feasting on hosta. Cicadas are still in full
flight in those areas where they are present. Sphinx moth
caterpillars are present. Oriental beetle adults are just
beginning to show up. Japanese beetles cannot be far behind. Plant
bug feeding was identified on herbaceous plant material. Spittle
bugs are quite evident on perennials. Lacebugs are active
on pieris, sycamore, and azalea. Mosquito populations are
quite active; green head flies are active in coastal areas. Black
spot is developing on susceptible roses.
Southeast
Region (Hanson) – General
Conditions: No report available this week.
East
Region (Boston) – General Conditions: Summer-like
with scattered thunderstorms and blustery winds.
Metro
West (Waltham) – General Conditions: No
conditions report available. See Environmental Data and Phenology
below.
Metro
West (Hopkinton) – General Conditions: We’ve
had frequent thunderstorms and tropical air prevailing in the
area. Pests/Problems: Have
seen the first signs of apple scab on susceptible plants.
Central
Region (Boylston) – General
Conditions: No conditions report available. See
Environmental Data and Phenology below.
Pioneer
Valley Region (Amherst) - General Conditions: Water
is standing in some fields after the northern portion of the
Pioneer Valley received over two inches of rain on Monday and
Tuesday morning this week. Lawns and landscapes continue
to be lush as the seasons advance this year. Daylilies,
primroses, and columbines mingle their colors with summer annuals
in gardens while northern catalpa as well as oakleaf and smooth
hydrangea are a tree and scrubs in full bloom. Pests/Problems: The
orange-yellow spots of cedar-apple rust and the gray-green blotches
of apple scab are visible on susceptible crabapple leaves. In
addition, an assortment of mushrooms is erupting in lawns.
Berkshire
Region (Great Barrington) - General Conditions: Frequent
thunderstorms have kept soil moisture high. However, many
of the storms have been severe, some with large hail stones,
and have caused localized damage to landscapes and gardens. Most
of the trees damaged by storms showed signs of internal decay,
branch dieback, and conks emerging from the trunks. Many
of these could have been classified as hazard trees. Municipalities
and private property owners need to be more vigilant with respect
to the health of trees that are located near structures, highways,
and walkways. Pests/Problems: No
new pest problems observed this past week
ENVIRONMENTAL DATA -
The following growing-degree-day (GDD) and precipitation data
was collected for a one-week period, June 18, 2008 through June
24, 2008. Soil temperature and phenological indicators were
observed on June 24, 2008. Accumulated GDDs represent the
heating units above a 50° F baseline temperature collected
via our instruments from the beginning of the current 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 |
2008 GROWING DEGREE DAYS
|
Soil
Temp
(°F
at 4" depth) |
Precipitation
(1-Week
Gain) |
1-Week
Gain |
Total
accumulation for 2008 |
| Cape Cod |
138 |
704 |
72° |
0.75" |
| Southeast |
n/a |
n/a |
n/a |
n/a |
| East |
121 |
773 |
70° |
0.50" |
Metro West
(Waltham)
|
124 |
706 |
68° |
1.50" |
Metro West
(Hopkinton) |
124 |
750 |
79° |
1.25" |
| Central |
124 |
688 |
62° |
2.55" |
| Pioneer Valley |
101 |
758 |
63° |
2.24" |
| Berkshires |
97 |
764 |
70° |
3.03" |
AVERAGE |
118 |
735 |
69° |
1.69" |
n/a = information not available
|
PHENOLOGY
-
The phenological indicators are a visual tool for
correlating plant development with pest development. The following
are the 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 |
METRO
W. |
CENT. |
P.V. |
BERK. |
Waltham |
Hopkinton |
|
 |
Oxydendron arboreum (Sourwood) |
* |
* |
* |
begin |
* |
* |
* |
* |
Lythrum salicaria (Loosestrife) |
* |
* |
* |
* |
begin |
* |
* |
* |
Stewartia pseudocamillia (Japanese
Stewartia) |
begin |
* |
begin |
* |
begin |
begin |
begin |
* |
Rhus typhina (Staghorn Sumac) |
* |
* |
begin |
b/full |
begin |
b/full |
full |
begin |
Tilia cordata (Littleleaf Linden) |
* |
* |
b/full |
b/full |
begin |
full |
full |
* |
Hydrangea arborescens (Smooth Hydrangea) |
begin |
* |
b/full |
* |
begin |
* |
full |
full |
Cotinus coggygria (Common Smokebush) |
b/full |
* |
b/full |
full |
begin |
full |
full |
* |
Ligustrum spp. (Privet) |
b/full |
* |
full |
* |
begin |
* |
full |
full |
Sambucus canadensis (American Elderberry) |
full |
* |
* |
full |
full |
full |
full |
b/full |
Itea virginica (Virginia Sweetspire) |
full |
* |
* |
* |
* |
full |
* |
b/full |
Cornus kousa (Kousa Dogwood) |
full |
* |
full |
f/end |
full |
full |
end |
full |
Cornus sericea (Red
Osier Dogwood) |
* |
* |
full |
* |
begin |
f/end |
* |
full |
Philadelphus spp. (Mock Orange) |
full |
* |
full |
end |
full |
end |
* |
full |
Syringa reticulata (Japanese Tree
Lilac) |
f/end |
* |
full |
end |
end |
f/end |
f/end |
full |
Rosa multiflora (Multiflora
Rose) |
f/end |
* |
full |
full |
full |
full |
f/end |
f/end |
Kalmia latifolia (Mountain Laurel) |
f/end |
* |
f/end |
end |
end |
f/end |
end |
full |
* = no
activity to report/information not available |
CAPE
COD REGION - Roberta Clark, Horticulturist for Barnstable County,
Barnstable.
SOUTHEAST REGION - Deborah Swanson, Horticulturist for UMass Extension
in Plymouth County, Hanson.
EAST REGION - James R. Allen, Horticulturist and Greenhouse Manager
for UMass Biology Department, Boston.
METRO WEST REGION – James Martin, Consulting
Arborist, reporting from the UMass Extension Center, Waltham.
METRO WEST REGION – Mark Sawyer, Horticulturist,
Weston Nurseries, Hopkinton.
CENTRAL REGION - Joann Vieira, Superintendent of Horticulture, Tower
Hill Botanic Garden, Boylston.
PIONEER VALLEY - Dan Gillman, Plant Pathologist, UMass Extension
Plant Diagnostic Lab, UMass, Amherst.
BERKSHIRES - Ron Kujawski,
Specialist, UMass Extension Landscape, Nursery & Urban
Forestry Program, Amherst.
WOODY
ORNAMENTALS
INSECTS
-
Lepidopteran Caterpillars:
-
Gypsy
Moth - No reports of large
numbers of this pest in MA have been received, yet. It
is assumed that numbers are low and that this pest
will be of little concern this year. This caterpillar
is now about two inches in length. Pupation
will begin soon in the warmer regions of the state.
-
Fall
Webworm -
The snow-white adult moths of this webworm have been found
attracted to porch lights at night in much of the state
now. Mostly, they go unnoticed. Larvae will
not appear until July, and their large silken webs on
the terminals of branches will not be seen until late
July or August.
Hymenoptera Sawfly (Caterpillar) Larvae:
-
Dogwood Sawflies − When
we encounter dogwood sawfly in MA on gray as well as redosier
dogwood it is usually Macremphytus tarsatus. The
larvae of this particular species start to appear approximately
mid July, and their activity can extend into the autumn months. As
the larva ages, they begin producing a white wax over their
bodies. This, along with their tendency to sit on the
foliage in a curled body shape, gives them the appearance
of a bird dropping. It is suspected this is a defensive
posture that they have evolved to avoid predation; no known
parasites or predators have been detected for this species. One
report from Plymouth County was received early this month
about sawfly caterpillars on dogwood. It was too early
in the season for it to be M. tarsatus. However,
there is another dogwood sawfly (M. varianus) that
appears to be little known, but it does occur earlier in
the growing season than M. tarsatus. It can
share the same host plants. It is suspected that this
is what was found. Both species consume all but the
main veins of the host foliage. If necessary, treat
either species with a product that contains spinosad. Very
young larvae can be treated with an insecticidal soap spray.
-
Imported Pine Sawfly - This
sawfly is more commonly found in the eastern parts of MA
than it is in the central and western parts. It will
become active by late June or early July. It shares
many of the same host plants as the European pine sawfly,
including mugo pine. Monitor for the yellow blocky
egg patches within needles. Remove and destroy needles
with eggs. Once the larvae emerge, treat with an insecticidal
soap or a product that contains spinosad.
-
Birch Sawfly − The
caterpillars of this pest are active and feed by wrapping
their bodies around the margins of foliage of birches as
they consume all but the main veins of the leaves. Although
not abundantly common in the state, it does appear somewhere
here every year and is capable of causing serious defoliation
if not treated. Spinosad products or one of the registered
pyrethroids work well. Also, insecticidal soap works
well when the larvae are still quite small.
Beetles:
- Japanese
Beetle
adults
will begin to appear by the end of next week. At
first, the numbers will be low but as more and more emerge
from the soil each day, this will change quickly. Make
note of those plants that may require protection.
- Asiatic
Garden Beetle
remains
active and is becoming more common, along with its feeding
damage. This small, robust and oval-shaped scarab
beetle is only active at night. It feeds on a wide
variety of deciduous landscape plants as well as many
different garden plants. Monitor at night with
a flashlight between the hours of 9 PM and midnight. This
pest can cause much ragged foliage to favored plants.
- Lily
Leaf Beetle
-
Adults, larvae, and eggs can all be found now. As
the larvae feed by skeletonizing the foliage, they begin
to cover their bodies with their own excrement. Entire
plants can be consumed to the soil if this pest is not
treated. Some adult beetles are still actively
mating and laying eggs. NEEM works well for the
larvae, once they appear, but needs to be reapplied every
10-14 days. Spinosad products also work very well
for the larvae. Adult lily leaf beetle is best
controlled with a pyrethroid insecticide.
- Viburnum
Leaf Beetle - Numerous reports
concerning new finds of this serious invasive pest have
been received from throughout Berkshire County. The
first find in Franklin County (Conway, MA) was recorded
just last week. Also, we received a possible find
in Bristol County. We are waiting for the adults
to appear to confirm its presence there; right now it
is damaged plant material. Inspect all viburnum
plants brought into the region from areas that already
have this pest. The larvae have dropped to the
soil and are undergoing pupation right now. Adult
beetles will emerge within the next 2–3 weeks. Spinosad
products work well for the larvae but not the adults,
which require something like a pyrethroid insecticide. Report
any new finds in MA to Bob Childs rchilds@psis.umass.edu or 413-545-1053. Treat
the same as for lily leaf beetle. For
current information about this pest, visit the Cornell
web site at http://www.hort.cornell.edu/vlb

- Imported Willow Leaf Beetle remains active. The
adult beetle is rather small, rounded, and metallic green/blue
in color. The adult beetles will chew holes into the
foliage, but it is the small black-colored larvae that create
most of the injury. Larvae will line up together on
the foliage and scrape the upper layers. This action
causes the still-intact leaf to eventually die and turn brown. This
pest has multiple generations per year, and its damage can
become severe by August when virtually all of the foliage
on a willow will appear bronze in color, as if fire-swept. All
willows are susceptible. Treating the adult beetle
requires a pyrethroid insecticide while a product that contains
spinosad works well for the larvae.
Piercing-Sucking Pests:
-
The Red-Banded Leafhopper (a.k.a. Sharpshooter
Leafhopper) will be arriving in MA any day
now from more southern states. This pale green
leafhopper with two chevron-shaped stripes on its back
is attracted to rhododendrons that continue to produce
new foliage through July and August. The egg-laying
in the new leaf tissue causes the leaves to become
stunted and distorted. It is purely an aesthetic
pest, but it can be an important pest, especially in
the nursery. Visually monitor for this insect
by gently shaking foliage to dislodge the leafhoppers,
which will fly up and then land again nearby. When
found in large numbers this pest should be treated.
-
Maple Leafhopper − This
is another leafhopper that migrates into the state every
year and is mostly attracted to maples in the landscape and
nursery. Their piercing sucking feeding can create
such extensive injury that foliage will appear to have been
damaged by bleach; very chlorotic yet finely stippled foliage. Monitor
visually by shaking branches. Treat if found in large
numbers.
-
Lacebugs remain
very active. These
serious pests always feed from the underside of the foliage,
but they create the fine, yellow stippling feeding injury
on the upper surface of the leaves. Look at the bottom
leaf surface of such affected leaves for the telltale signs
of the brown fecal spots and the lacebugs themselves. Inspect
common host plants for this pest for last year’s
damage. Common hosts are: Japanese andromeda,
evergreen azaleas, rhododendron, cotoneaster, and hawthorn. Systemic
imidacloprid appears to be quite effective for managing
this pest. Also, horticultural oil sprays or insecticidal
soap sprays that are targeted to the foliage underside
is also effective for the small nymphs. Susceptible
plants growing in sunny areas will experience more damage
given that heat greatly encourages lacebug populations.
-
Miscellaneous Aphid species are
appearing now and building in numbers. Monitor for
honeydew and sooty mold. Treat if necessary. Systemic
imidacloprid, or insecticidal soap sprays, or horticultural
oil sprays are all effective treatments. Maples, catalpa,
tuliptree, lindens, and many others are common hosts.
-
Taxus Mealybug remains active. Move
the foliage of taxus back and inspect the inner branches
and smaller stems for white, cottony masses. This
insect produces honeydew, which leads to the unsightly
buildup of sooty molds. Also, large populations can
cause stunting and chlorosis of the foliage. Treat
with a systemic imidacloprid product or spray the inner branches
and stems with either a horticultural oil spray or one of
-
Spider Mites - Inspect
spruce, hemlock, fir, and others for the signs of feeding
damage by these tiny but very prolific and potentially damaging
pests. Inspect very closely
for the active mites, which will require a good hand
lens or microscope. If found, treat with an oil
spray or with one of the new mite growth regulators. Monitor
for the actual mites by shaking a branch over a white
piece of paper and then inspecting with a hand lens for
the mobile mites.
-
Hemlock
Woolly Adelgid  -
The second generation is becoming active. Much
feeding is occurring now. This pest will go
dormant in another 3-4 weeks, but it can still be managed
even in that stage. A horticultural oil spray
at the summer rate (be careful of tender new foliage
now emerging), systemic imidacloprid, or systemic
dinotefuran (Safari™) are all effective against
this very serious pest. Note: Safari™ is
a State Restricted Use pesticide in Massachusetts. (See
Elongate Hemlock Scale, which appears next.)
-
Elongate Hemlock Scale (aka
Fiorinia Scale) − Inspect hemlocks
closely for this pest. If the plant appears weakened
or sickly and has hemlock woolly adelgid, which is very
obvious, take the extra time to closely inspect the undersides
of the needles for this scale. Fiorinia scale is
very small, brown and mostly oval in shape. Many
of these may be present per needle (on the underside only). In
some cases, it will be the primary reason that a hemlock
looks to be in ill-health. Imidicloprid, which works
pretty well systemically for hemlock woolly adelgid, does
not have much of an impact on this scale. Horticultural
oil sprays, which also work well on hemlock woolly adelgid,
tends to provide minimal control for this scale. Safari™ (dinotefuran),
a relatively new neonicotinoid, does show good promise
for fiorinia scale and works well when utilized as a systemic. However,
in Massachusetts, it has a “State Restricted Use” labeling
due to groundwater concerns. Fiorinia scale is difficult
to control. Unlike most armored scales in the Northeast,
it produces crawlers throughout much of the growing season. If
found, treat it aggressively. Fiorinia scale is a
very serious pest of hemlock and can occur on conifers
other than hemlock.
-
Cryptomeria Scale was
found on Cape Cod last fall as well as in Rhode Island (not
far from the MA border). This was the first time that
this scale has been found in MA. Two finds were on
Christmas trees—both firs—in the nursery (plantation). This
scale attacks various conifers and has the potential to be
a serious pest. Inspect needles for yellowing (stippling)
and the presence of the scale on the needle undersides. Treat
with a horticultural oil if found.
-
Cottony Camellia Scale (aka
Cottony Taxus Scale) remains active. Inspect
the foliage of taxus and certain hollies for white,
oval and waxy scale coverings. If found, inspect
foliage further for the tiny yellow nymphs which have
overwintered on the twigs and have now migrated to
the foliage. This pest has been actively feeding
already this spring. If this pest was active
last year, then look for the buildup of sooty molds
as well. Larger population numbers can contribute
to poor plant growth and unsightly sooty mold. Systemic
imidacloprid or dintotefuran (Safari™) should
be effective. Oil sprays also are effective but
be careful with their use on hollies, which may be
sensitive to oils.
Leaf Miners:
-
Arborvitae Leafminer − There
are two species of what is commonly called “Arborvitae
Leafminer” in Massachusetts. The more common
species remains within the foliage as a larva until early
to mid June whereupon it pupates (within the foliage) and
the tiny off-white moths then appear around mid to late June. The
adult moths are not attracted to yellow sticky cards, so
to monitor for their presence, gently shake foliage to dislodge
the moths. Treat with a pyrethroid insecticide when
the adults are found to prevent reinfestation. The
other species, which is more common in coastal areas of MA,
emerges early in the season and spins a small silken cocoon
that slightly resembles a fuzzy grain of rice. In large
numbers, there may be countless numbers of these cocoons
visible on the foliage. Again, wait for the adults
to emerge and treat the same as the other species. Eggs
of both species are deposited on the foliage and not within
the foliage. A well-timed horticultural oil spray may
be effective for managing these eggs, but timing is essential. Most
eggs (both species) will be on the undersides of the foliage.
-
Native Holly Leafminer − This
pest of American holly has been in the foliage as a larva
since last June. It creates a serpentine
(winding) mine initially. It then settles in one
part of the leaf and makes a large blotch mine. Several
mines may be present per leaf when it occurs in large
numbers. Pupation will begin soon, and the
adult flies start to emerge around mid June. Monitor
for the adult flies with yellow sticky cards and
treat with a pyrethroid insecticide when present to prevent
re-infestation.
Wood Attackers:
-
Bronze Birch Borer − The
adults of this pest are beginning to emerge now and will
continue to emerge and be active into September. This
pest kills trees, but it can only survive in previously weakened
trees. Keep trees healthy to avoid attack. Drought
stressed trees (so far, not a problem this season) are candidates
for attack as are old trees or those growing in compacted
soils. Treatments become a challenge once infestation
occurs. Some arborists do not like to prune birches
from June into September to avoid releasing plant volatiles
that may attract beetles. However, if the tree is healthy,
then there should be little concern for colonization by this
insect.
-
Dogwood Borer − This
clear-winged moth will be active and seeking wounded dogwood
trees from now until late August. The females deposit
eggs near bark crevices, such as branch collars, and around
wounds. The wood-boring caterpillar of this species
tunnels into the cambium and later into the older wood. Signs
of an infestation now will be sap exudation on the trunk
and scaffold branches. Avoid wounding dogwood trunks
with mowers and line trimmers. Pheromone traps are
available to monitor for the adult moths. This caterpillar
pushes out the sawdust as it tunnels thus leaving its tunnels
open, unlike most wood borers. Nematode products sprayed
on the trunk are extremely effective for new infestations.
Other Stuff:
- White-Spotted Pine Sawyer (WSPS) is
now active as an adult. This adult beetle is commonly
confused with Asian Longhorned Beetle (ALHB), which has never
been found in MA. WSPS is native and is only attracted
to very weak or freshly dead pines. It is not considered
to be a pest.
A Few Comparisons/Differences Between ALHB and WSPS:
- ALHB has a very shiny black body, like that of patent
leather; the pine sawyer is more of a dark mottled grey.
- ALHB has crisp white spots; pine sawyer has more diffuse
white spots.
- ALHB has a blue-ish cast to the color of its tarsi (feet);
pine sawyer does not.
- Both have antennal segments that alternate between white
and black.
Reported by Robert Childs, Entomologist, UMass Extension Landscape,
Nursery and Urban Forestry Program, Amherst
Mushrooms in lawns often develop from thatch,
buried logs, dead roots, stumps, or even construction debris. They
have many different sizes, colors, shapes, and habits of growth
and develop fruiting structures or mushrooms in lawns after
prolonged wet weather. The fungi that produce these mushrooms
are beneficial because they decompose organic matter in the
soil, making nutrients available to other plants. These
mushrooms usually are harmless to grasses, but some people
consider them unsightly or want to get rid of them because
young children play in the area. Neither spray applications
nor drenches of fungicides are effective in controlling these
mushrooms. Simple way to remove mushrooms is to mow the
lawn while collecting the clippings or by raking them up. Elimination
of excess thatch and aerating the soil to improve water penetration
also helps in some cases. In addition, the mushrooms
gradually disappear without interventions if the weather becomes
drier.
Horsechestnut
(Guignardia) leaf blotch is
visible as scattered, irregular-shaped orange-brown blotches
on infected leaves. They are primarily affecting
lower, inside leaves. However, as the summer progresses
the impact of the disease may be more noticeable, but chemical
intervention at this time for this season is of little
benefit. Keep in mind that horsechestnuts infected
year after year continue to grow vigorously in spite of
Guignardia leaf blotch. However, if appearance is
important, begin fungicide applications as buds break open. If
wet conditions persist, reapply 1-2 additional treatments
at labeled intervals.
Powdery
mildew fungi
are visible as a dusty, gray to white areas on red horsechestnut
(Aesculus x carnea), dogwood, sycamore,
phlox, and roses, to name a few. Once established
on plants, powdery mildews grow superficially on both upper
and lower leaf surfaces as well as green shoots and flower
buds. They are obligate parasites and derive sustenance
only from living host plants. They do this using
minute, tube-like structures (haustoria) that penetrate
the epidermal cells and draw out material they need to
survive. Later this summer spherical, black fruiting
structures are visible with a hand lens on the underside
of leaves in the dusty, gray mycelia. Generally,
the damage caused by powdery mildew is of minor consequence
to healthy plants and does not warrant chemical control
if unsightliness is not a critical concern. If considering
chemical control there are a number of unconventional applied
materials labeled to protect susceptible plants. They
include summer horticultural oil, commercial baking soda
preparations (sodium bicarbonate and potassium bicarbonate),
anti‑transpirants, as well as a number of conventional
fungicides. Chemical spray programs are most effective
when begun just as symptoms of powdery mildew begin to
show. Once powdery mildew is extensive on the plant,
there is little benefit from chemical control that season. Applications
need to coat both surfaces of all susceptible plant parts
to prevent infection. Spray on a regular schedule,
and repeat more often during warm, humid weather.
Reported by Dan Gillman, Plant Pathologist, UMass Extension
Plant Diagnostic Lab, Amherst
LANDSCAPE
TURF
INSECTS -
Armyworms − We have had an unconfirmed
report of an armyworm (Pseudoletia unipuncta) infestation
attacking a low maintenance turf area in the metropolitan Boston
area. The report is "unconfirmed," since I have
not personally seen samples of the caterpillars, but is pretty
likely to be accurate. I was able to send digital photos
of armyworms to the turf manager, and he confirmed that his specimens
looked just like my pictures.
In their medium and larger stages, the caterpillars are very
dark (described as black or navy) on the top, with a straw-colored
stripe along the side of the body. The head capsule has
two shades of brown (dark and light) with a kind of "honey-comb" pattern. And
the fleshy legs on the abdomen usually have a dark stripe near
where the leg attaches to the body.
Some of you will remember the remarkable infestations that appeared
during June 2001 in some parts of southern New England. In
that case we believe the armyworms were blown in (while in the
moth stage) from New Jersey and other regions south of New England
during a large coastal storm early in June. Many turf managers
that year reported caterpillar infestations of "biblical
proportions"—the caterpillars emerged in incredibly
high densities and marched, like an army, across turf areas and
pavement, leaving death and destruction in their wake.
We have not yet heard of other reports of armyworms, so I don't
know whether this latest report will turn out to be an isolated
instance or whether we may see large areas affected like in 2001. If
the activity turns out to be more widespread, I offer the following
suggestions:
- If the caterpillars are already nearly full sized (they
typically reach 1.25 inch in length during their last instar),
there are no chemical or biological control strategies that
will provide significant levels of control. In that
case, about the only thing you can do is minimize stress
on the turf. Raise
the mowing height a bit (to try and increase the photosynthetic
surface), which may help the turf a little. And if possible,
water the area as needed, again to help the turf through
the stress period.
- If you notice the caterpillars early enough that they are
still small (less than half an inch), you should achieve
reasonable levels of control – at least knock the population back
to a dull roar. You can use a pyrethroid or carbaryl
(Sevin™). In addition, a product containing spinosad
(often sold as Conserve™) provides good control of
many caterpillars; and while I don't have any data either
way, it might also be effective against armyworms.
Sod webworms − I have had an unconfirmed
report of sod webworms activity in central Massachusetts (Sterling
area). The turf manager reported that webworm moths were
flying in the area, and that some turf appeared to be showing
damage from caterpillars. While that report is unconfirmed,
I went home that evening and noticed that large numbers of webworm
moths were flying in my own lawn, so I fully expect that the "diagnosis" was
accurate.
In most cases we do not see damage from sod webworms in New
England, but it does occasionally happen. There are several
species of webworms, each of which produces caterpillars that
feed in the turf and can leave straw-like patches of dead grass. Several
of the webworm species spend the winter in New England in a late
caterpillar stage, feed briefly in the spring, and then pupate
and emerge as moths. These are the moths that flit aimlessly,
just above the turf, dropping eggs as they go.
Again we normally do not see damage from these insects, but
there can be exceptions. If you have reason to believe
that the damage your turf incurred a couple weeks ago was caused
by webworm caterpillars and you see webworm moths flying now,
consider applying a pyrethroid in the area about a week or two
after peak moth flight. That gives the moths time to produce
and lay eggs and the eggs to hatch into tiny caterpillars. Water
very lightly, just enough to knock the material off the blades
and into the thatch.
Reported by Pat Vittum, Extension Entomologist, UMass Department
of Plant, Soil and Insect Sciences, Amherst.
IMPORTANT
INFORMATIONAL RESOURCES
Check out this new fact sheet on Problem Soils 
For
a complete listing of upcoming events, see our Conferences
and Workshops page.
Don't forget to visit the UMass
Extension Online Weed Herbarium!
2008-2009 Professional Management Guide
for Insects, Diseases and Weeds of Trees and Shrubs in New
England - Pesticide label
registration changes every year in all states and you can only
legally apply pesticides according to the current year's label.
This updated 2008-09 guide tells you what is current and legal
for use in all the New England states and is the way for you
to stay current with pesticide information. If you already
have the 2003 version, this is the updated supplement for pesticide
information. Remember, if you're a pesticide applicator, it's
the law! Created by UMass Extension professionals, this manual
offers the latest on virtually all the insects, diseases, and
weeds of woody plants in New England; current and legal listings
of chemical compounds labeled for the management of these pests;
Integrated Pest Management (IPM) considerations for most of
these pests; environmentally friendly alternatives in pest
management such as horticultural oils, soaps, biologicals,
etc.; and Growing Degree Day (GDD) information for most of
the insect pests of woody plants. Click
here to order online from the UMass Extension Bookstore or
contact (413) 545-0895; eweeks@umext.umass.edu for information.
Planting and Maintaining Sustainable
Landscapes: A Guide for Public Officials and the Green Industry -
An updated and reprinted collection of fact sheets, including
Trees and Shrubs for Low Maintenance Landscapes; Recommendations
for Planting and Maintaining Trees and Shrubs; Integrated
Pest Management and Plant Health Care; Streetscape Design
and Planting; Selecting Turfgrasses for Low Maintenance Sites;
Turf Pesticides and the Environment; Children's Protection
Act and School IPM Plans; and Guidelines for Planting within
the 100 Foot Wetland Buffer. Click
here to order online from the UMass Extension Bookstore or
contact (413) 545-0895; eweeks@umext.umass.edu for
information.
DIAGNOSTIC
SERVICES
UMass Laboratory Diagnoses Turf and
Landscape Problems - Accurate
diagnosis for a turf or landscape problem can often eliminate
or reduce the need for pesticide use. 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. Send
specimens and payment (payable to the University of Massachusetts)
to UMass Extension Plant Diagnostic Lab, Holdsworth Natural
Resources Center, 160 Holdsworth Way, UMass, Amherst,
MA 01003. The fee for a woody plant disease analysis
is $50; the fee for turf disease analysis or nematode
assay is $75. All insect, weed and turfgrass identification
samples are $25 each. For more detailed submission instructions
see http://www.umass.edu/agland/diagnostics 
Soil and Plant Tissue Testing - The University
of Massachusetts Soil and Plant Tissue 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 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 Soil and Plant tissue Testing Laboratory web site at: http://www.umass.edu/plsoils/soiltest Alternatively,
call the lab at (413) 545-2311.
NEXT UPDATE: The next issue will be available
on July 10, 2008.
This message is produced by the
UMASS Extension, Landscape, Nursery and Urban Forestry Program.
The copy is prepared by Anna Greene from data and reports provided
by the staff and faculty of the UMass Landscape, Nursery and
Urban Forestry Program and the UMASS Extension Turf Program as
well as cooperating horticulturists and Green Industry professionals.
The text is adapted for access via the Internet by Jason Lanier.
DISCLAIMER. This
message is intended for commercial use. UMass Extension assumes
no liability for recommendations. It is the responsibility
of the applicator to verify the registration status of any
pesticide BEFORE applying it. Different states have different
regulations as well. The use of trade names (™) does
not imply endorsement. Similarly, there may be other products
you prefer to use.
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