The Colorado potato beetle, an adaptable pest that ravages potatoes,
tomatoes, and eggplants, has developed resistance to many of the methods
that are used to control it. To prevent this resistance and to learn more
about how beetles develop it, researchers in Maryland have launched several
projects with growers and other collaborators.
One project focuses on populations of Colorado potato beetle that are
susceptible
to the New Leaf transgenic potato. This commercially available potato has
been genetically altered to contain a gene from the bacterium Bacillus
thuringiensis,
known as Bt. The gene produces a protein in the potato, making it resist
the beetle. Never before have baselines been established on susceptible
populations before a new pest management method is introduced.
Collaborators in two Canadian provinces and 13 states (many from the Northeast)
collected 79 susceptible populations of potato beetles from commercial farms.
These populations showed significant variation in susceptibility and have
already been compared to resistant, laboratory-reared beetles. As growers
in the collection regions employ the New Leaf potatoes, scientists and growers
will look at whether the beetle populations change. Early detection of changes
will spur the use of alternate tactics to prevent resistance.
Related studies, begun in 1995, involve limiting the application of a new
insecticide to preserve its usefulness over time. On a dozen potato farms,
a 100-foot wide strip around the perimeter of the field was treated with
the insecticide imidacloprid. This toxic barrier prevented migrating beetles
from walking into new potato fields. Use of imidacloprid was cut by 50 to
95 percent of conventional applications, and beetles were controlled for
at least 90 days after treatment. Control costs were 75 percent less than
the cost of treatments for whole fields. Results from these ongoing studies
have already begun to benefit farmers throughout the region.
State IPM Coordinator, Agriculture
Betty H. Marose
2328 Symons Hall
Dept. of Entomology
University of Maryland
College Park, MD 20742
301 405 3929; bm7@umail.umd.edu
State IPM Coordinator, Urban
Michael J. Raupp
1300 Symons Hall
Dept. of Entomology
University of Maryland
College Park, MD 20742
301-405-3943; mr7@umail.umd.edu
return to IPM in the Northeast Region 1996 Report, Table
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