Landscape Message: May 13, 2016

A Request for Bruce Spanworm: A graduate student working
with Dr. Joseph Elkinton on winter moth is looking for outbreak
populations of winter moth’s native counterpart, Bruce spanworm. This
insect harbors a microsporidian, a type of parasitic fungus, that is not
found in winter moth populations. This may explain why Bruce spanworm
very rarely has outbreaks and when they occur, the outbreaks are very
short-lived, whereas winter moth is in permanent outbreak phase in
Eastern New England. Populations of Bruce spanworm are needed to conduct
further research. Bruce spanworm can be found on a wide range of
deciduous trees. The caterpillars are bright green inchworms,
3/4-inch-long, and leave behind Swiss cheese patterned holes in the
leaves. See this USDA pest alert or this summary by the Maine FS
for some photos of the caterpillars and their damage. The defoliation
occurs right after bud break and there is only a week to collect before
the caterpillars drop down to pupate. If you know of a population of
Bruce spanworm, particularly in western Massachusetts, that could be
collected for this research, please contact either Dr. Elkinton (elkinton@ent.umass.edu) or Hannah Broadley (hbroadley@cns.umass.edu) as soon as possible.