Ithaca, New York
June 8, 2006
Source:
Cornell Chronicle
By Kara Dunn
"Clean" sweet corn is not easy to
grow, but organic and no- or low-spray growers are successfully
dealing with potential pest infestations using tiny wasps so
consumers won't find little worms when they husk their corn.
Five farm families are working with Abby Seaman, vegetable
integrated pest management (IPM) extension educator of Cornell
University's IPM Program, and Mike Hoffmann, Cornell professor
of entomology, on a project funded by the farmer-led New York
Farm Viability Institute to grow corn without chemical
pesticides. The institute provides New York's farmers and
growers with access to a network of production, business
planning, marketing and agricultural and horticultural
specialists that includes Cornell faculty and extension
educators.
The farmers tested the use of tiny Trichogramma ostriniae wasps
as natural predators that attack the eggs of the European corn
borer and an all-season pest, the fall armyworm. Pheromone traps
monitored moth activity as a gauge for timing three releases of
the wasps. The growers evaluated spraying an insecticide
approved for organic production and applications of a
Bt-microbial insecticide (its bacteria produce toxins) mixed
with soybean oil put directly on the corn silks as control
methods for a late-season pest, the corn earworm.
Successful application of the natural pest controls to prevent a
25 percent loss of a sweet corn crop can mean as much as $750
per acre in sales for an average harvest of 1,000 dozen ears per
acre and, an average selling price of $3 a dozen. In years of
severe infestations when 75 percent of a crop could be lost,
preventing that loss can mean as much as a $2,250 difference in
sales per acre.
Worm-free corn also makes customers happier and more likely to
purchase other farm products.
"We saw the most worm-free corn we've ever had, and our
customers were quite pleased. That positive response impacted
the sales of all of our farm market products," says Mike Thorpe
of Thorpe's Organic Family Farm in East Aurora, N.Y., who
participated in the project with his wife, Gayle.
"The control we had with the wasps in 2005 was better than with
our past use of insecticides," says Dave Henderson, who grows
unsprayed corn in Penn Yan, N.Y.
Henderson and Thorpe were two of five organic or no-spray
growers providing a total of 36 acres of sweet corn for field
trials.
In a customer survey at each farm, 91 percent of respondents
were satisfied with the quality of the corn. All the farms
market their corn directly to consumers.
"Control with wasps will naturally be more variable than the
consistency achieved with insecticide application, but the
results will most of the time satisfy customers that prefer
direct market purchase of organic or no/low-spray products,"
Seaman says.
The wasps used in this project can be purchased from IPM
Laboratories in Locke, N.Y. |