Model Helps Time Stored Pest
Most U.S. warehouses fumigate three or four times a year to control moths
and other stored product insect pests. Fumigation--costing about $20,000 each
time--is initiated even when only two or three moths are sighted in the
"Fumigating when there are so few insects is a costly waste," says
Agricultural Research Service
entomologist James E. Throne. He works at the U.S. Grain Marketing Production
and Research Center in Manhattan, Kansas.
"Better timing can be achieved by having an accurate count of how many
insects are present and knowing their stage of development. With this
information, warehouse managers can keep costs down and reduce the amount of
Throne and entomologist David W. Hagstrum have developed a computer model
for tracking development of the almond moth, a major pest of grain and other
stored products throughout the world.
In 1996, using data gathered by Polish entomologist Jan Nawrot, ARS
scientists developed a computer model that simulates the life cycle of almond
moths on stored peanuts. Shortly after, they modified the model to simulate the
moth's life on stored corn and dried citrus pulp. The basic data blocks of the
model show how temperature and moisture conditions affect the number of adult
moths, how many eggs each adult can lay, and how long it takes for immature
moths to complete development.
"Our predictions can help warehouse managers decide when to use
alternatives to insecticides. For instance, we know that cooler temperatures
can reduce or stop moth reproduction and slow development of immature
moths," says Throne. "It may take only a slight temperature drop, say
from 75oF to 65oF, to curtail moth activity."
Turning on fans to cool down the warehouse is much less expensive--and more
environmentally safe--than fumigating.
Now the researchers are adapting the computer model for predicting
Indianmeal moth development in corn and other stored products that can harbor
the pest. These moths are responsible for large expenditures by the
multibillion-dollar food industry for sanitation and insecticidal
treatments.--By Linda Cooke
McGraw, Agricultural Research Service Information Staff.
James E. Throne and
David W. Hagstrum are in the
USDA-ARS Biological Research Unit,
U.S. Grain Marketing and Production Research Center, 1515 College Ave.,
Manhattan, KS 66502; phone (785) 776-2796, fax (785) 776-2792.
"Model Helps Time Stored Pest Fumigation" was published in
the July 1998 issue of Agricultural Research magazine. Click here to see this
issue's table of contents.