[MPWG] Summer Bug Outbreaks

[Patricia_DeAngelis at fws.gov]

This press release may be of interest to East Coast NTFP harvesters and
consumers...I share Bob's concern about tapping insecticide-laden maple
trees, not to mention the potential to affect understory vegetation...

Patricia S. De Angelis, Ph.D.
Botanist - Division of Scientific Authority
Chair - Plant Conservation Alliance - Medicinal Plant Working Group
US Fish & Wildlife Service
4401 N. Fairfax Dr., Suite 750
Arlington, VA  22203
703-358-1708 x1753
FAX: 703-358-2276
Working for the conservation and sustainable use of our green natural
resources.
<www.nps.gov/plants/medicinal>


Press release to all media by Bob Beyfuss Cornell Cooperative Extension of
Greene County

                         Leaf Eating Caterpillars

     It has been 16 years since we had a serious gypsy moth outbreak in
this region but I am afraid some parts of the Hudson valley will see some
complete defoliation this year. Much of southern Greene County including
Palenville, parts of Catskill, Saugerties, Haines Falls and parts of Acra
have already had close to 50% defoliation which means that all the leaves
will be gone by July. Gypsy moths prefer oak although they eat more than
100 other plant species. The good news is that healthy trees will produce
another crop of leaves later this summer and the past two good growing
seasons have allowed many trees to store adequate food reserves that should
allow them to survive this outbreak.
     This is actually a very unusual season in that at least 5 different
species of leaf eating caterpillars are having population explosions all at
the same time. A few weeks ago I wrote about eastern tent caterpillars
which feed primarily on wild cherry and forest tent caterpillars which feed
mainly on sugar maple. The forest tent caterpillar is much more of concern
to me than the eastern tent, which is about done feeding by now. Much of
the annoyance of eastern tent caterpillars right now is due to their
congregating on houses, barns etc in great numbers. Almost any “over the
counter” insecticide spray will usually kill these pests if sprayed
directly on them.I am still not certain what the extent of damage will be
from the forest tent caterpillar but I am concerned for our maple syrup
producers, especially in the Mountain towns.
     A different caterpillar has been defoliating honey locust and black
locust trees. This pest is also just about finished feeding now but many
locust trees from East Durham, Greenville, Coxsackie and elsewhere are
already defoliated.Yet another caterpillar, a cankerworm also called an
“inchworm” or “looper” because of they way they move by arching up their
back has been working in the forest feeding on maples, ash, witch hazel and
almost everything else except for evergreens. I spent much of Memorial Day
weekend in the forest and the “ballooning” webs that the caterpillars spin
as they descend from the tree made walking around almost unbearable in some
places.
    OK, so what can we do about these leaf eating pests? Well, the correct
ecological answer is to let them run their cycle and do nothing. Healthy
deciduous trees will refoliate another crop of leaves later this summer
which will allow them to survive. Eventually, this season or next these
caterpillar populations will crash as abruptly as they appeared. Once this
occurs they will not return for many years (hopefully). By the end of June
all of these pest will have ceased feeding for this season.
     Important landscape trees and shrubs may be sprayed with the
biological pesticide called Bacillus thurigeinsis, sold as Dipel, Thuricide
or Organic caterpillar killer among other brand names.  This is a stomach
poison and must be ingested by the insects. It also takes a few days to
kill them but their feeding stops within hours. A relatively safe chemical
insecticide called carbaryl (sold as Sevin among other brand names) will
kill these pests both by contact and by ingestion as will several other
insecticides sold over the counter. If you would like a fact sheet on any
of these leaf eating caterpillars call us at 518 622-9820. Be sure to have
several of the caterpillars in front of you so we can help you identify
them and send you the correct fact sheet.