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Ithaca, New York
February 13, 2002
The latest in insect control:
"cotton candy."
One day farmers might exchange
pesticides for an industrial grade polymer that looks and
acts like cotton candy as a major weapon against onion
maggots, cabbage maggots, corn earworms and other
agricultural pests. Michael P. Hoffmann, Cornell University
professor of entomology and director of the university's New
York State Integrated Pest Management program, and his
colleagues have been testing nonwoven fiber barriers made of
ethylene vinyl acetate, or EVA, as a bug-prevention device.
The polymer, identical to the material used in hot-melt glue
guns, can be extruded under pressure to form webs that cover
plants and appear to ward off agricultural pests.
Says Hoffmann: "The best way to
envision these barriers is to think of cotton candy just
like you buy at the circus, except remove 99 percent of the
fibers and what remains is a nonwoven multidimensional
barrier that can be strategically placed to interfere with
insect behavior."
Hoffmann will introduce this
new pest management tool in his talk, "Novel Pest Management
Tactics: Pushing the Envelope," at the 2002 New York State
Vegetable Conference Feb. 13 at 10 a.m. in the Holiday Inn,
441 Electronics Parkway, Liverpool, N.Y.
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Ethylene vinyl
acetate (EVA), nicknamed 'cotton candy' by Michael Hoffman,
keeps insects from attacking this broccoli plant.
Credit: Baird/Cornell
Copyright © Cornell University |
Nonwoven fiber barriers hold
considerable potential for the management of onion maggots and
cabbage maggots, says Hoffmann. Without any pest controls in
place, as much as 90 percent of a cabbage crop can be destroyed,
and as much as 40 percent of untreated onions can be wiped out.
Currently, onion and cabbage fields generally rely on
insecticides at planting to control maggots. Long-term reliance
on insecticides is problematic because of the continuing threat
of the development of resistance to the chemicals. "The need for
alternative control measures for both the cabbage maggot and the
onion maggot is critical," says Hoffmann.
Onion maggots use their hook-shaped mouthparts to feed on young
onions, ultimately killing the plant. The feeding also permits
the entrance and spread of fungal and bacterial pathogens to
onions.
Cabbage maggots burrow into the plant's main roots so that the
plant wilts and dies.
In Hoffmann's field-cage experiments, the scientists learned
that placing EVA fibers around the base of onion plants
significantly reduces the number of eggs laid by female onion
maggots. EVA-treated plants had an average of 1.4 eggs per plant
compared with an average of 10.4 eggs for untreated plants.
During a cabbage maggot field-cage experiment, the researchers
applied EVA to young broccoli plants. While the polymer appeared
to inhibit the leaves unfurling for a week or two, the leaves
broke free of the barrier and were unaffected by the fiber mat,
says Hoffmann.
The nonwoven fiber project is still in the early stages.
Currently, the material is too expensive and impractical for
large-scale agricultural use. "We started with EVA because the
material and delivery technology let us produce an array of
fiber types for testing the effects of fiber density, diameter
and color, and permitted the addition of repellents, such as
capsaicin from hot peppers," says Hoffmann.
"One day we hope to use fibers with proper characteristics for
pest repellence and timed degradation so that the barriers
remain intact only as long as necessary. The technology exists,
and it's just a
matter of pushing forward with more research and development,"
he says. These weblike barriers also hold considerable potential
for several other insect pests, birds and possibly even deer.
Joining Hoffmann on the research was postdoctoral associate
Thomas P. Kuhar, now assistant professor at Virginia Polytechnic
Institute and State University; and Jeffrey Gardner, research
support specialist in entomology, and Peter Schwartz, Department
of Textiles and Engineering, Auburn University, Ala. Joel Baird,
former Cornell researcher in entomology, contributed to the
preliminary fiber
studies.
Research funding came from a grant from the U.S. Department of
Agriculture's Cooperative State, Research, Education and
Extension Service (Pest Management Alternatives Program) and the
Environmental Protection Agency (Pesticide Environmental
Stewardship Program). Funding also came from Cornell
Agricultural Experiment Station federal formula funds.
Contact: Blaine P. Friedlander
Jr.
Office: 607-255-3290
E-mail: bpf2@cornell.edu
Cornell University News Service
Surge 3
Cornell University
Ithaca, NY 14853
607-255-4206
cunews@cornell.edu
http://www.news.cornell.edu
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