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Project Leaders: Margaret Smith, Department of Plant Breeding, Cornell University,
and Laraine Ericson, Keith Payne, Department of Plant Breeding, Cornell
University
Cooperator(s):
John Losey, Department of Entomology, Cornell University
Leslie Allee, Department of Entomology, Cornell University
Type of Grant: Pest resistant crops.
Project Location(s): Throughout the Northeast.
Abstract:
Corn hybrids that have been genetically engineered with the Bt gene
for resistance to corn rootworm offer growers in New York an interesting
option for control of this pest. These hybrids would eliminate the
need for soil-applied insecticides in many corn fields, but also require
planting 20% of the area of the field with a non-genetically engineered
variety (called a “refuge”) to ensure that Bt-susceptible rootworms
continue to predominate in the rootworm population. Finding corn hybrids
that are well adapted for refuge plantings will reduce the need for
insecticide use in refuges, increase profitability from refuge plantings,
and make it more likely that farmers will comply with the refuge requirement.
Ideal refuge hybrids would suffer relatively little from corn rootworm
damage (either because larvae do not damage them much or because they
can regrow roots well and thus recover from the damage) and yet produce
many adult rootworms to ensure that the rootworm population remains
mostly susceptible to Bt. Our research was designed to identify such
ideal refuge hybrids. Nine corn hybrids that are widely sold in New
York were grown in plots that were infested with corn rootworm eggs
and in plots that were not infested. Ratings of root damage and root
regrowth after damage were made, and cages were installed in each
plot to collect and count how many adult rootworms emerged. Based
on just this initial year’s data, one hybrid appeared to be
especially promising as a refuge hybrid, because it had excellent
root regrowth and large numbers of adults emerged. It will take several
more years of collecting data to confirm this result, and we will
need to collect yield data (which is essential to evaluating damage
to hybrids from rootworms, but could not be collected in 2003 because
circumstances forced a very late planting date). In future years,
we will be collecting data not only on rootworm damage, root regrowth,
and adult emergence, but also on hybrid maturity, standability, and
yield. This will provide a data set that will allow us to identify
highly productive hybrids that serve as excellent refuge hybrids,
thus providing growers with options to reduce or eliminate pesticide
use in refuges, obtain more yield from them, and promote the effectiveness
of genetically engineered Bt rootworm resistant corn in the future.
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