Trichogramma deion wasp is about 1/2 millimeter in length. Bottom: larva
of Plodia interpunctella, the Indianmeal moth.
(Wasp image courtesy P. Flinn)
Special "Sting" Operation Could Guard Grocery
Goods from Buggy Pests By
Erin Peabody June 17, 2005
It's possible that sometime in the future, as you stroll the aisles of
your local grocery, armies of miniature wasps will be on patrol in your midst,
keeping watch over packages of cornflakes and cartons of oats.
Harmless and practically invisible, parasitic wasps are an effective
and Earth-friendly way to keep serious food pests in check, according to
Flinn, a biologist with the Agricultural
Research Service at Manhattan, Kan.
One of the most problematic and costly insects in retail and warehouse
environments is the Indianmeal moth. Its larvae can infest stored
products--like bags of grain, cereal or pet food--and even chew through
protective packaging. Adult female moths are very efficient at reproduction,
laying as many as 300 eggs in just one week.
Traditionally, the moths have been controlled with chemical fumigants
or fogs. But Flinn wondered if the moth's natural enemies--wasps in the genus
Trichogramma--could be as effective. To explore this possibility, he
teamed up with Matt Grieshop, who recently completed his Ph.D. on this work at
Kansas State University in Manhattan.
They found that T. deion, a wasp no bigger than a speck of
dust, was able to zero in on, sting and kill the moth eggs. The wasps worked
best when the researchers released them in fairly simple environments, where
moth eggs had been placed on shelves or on top of product packaging.
When Trichogramma wasps were paired with another tiny parasitic
wasp from the genus Habrobracon, the results were even better. According
to Flinn, Trichogramma goes after the moth eggs before they can develop
into damaging larvae. Habrobracon finishes the job by killing any larvae
that develop from eggs that Trichogramma may have missed.
Growers have been using Trichogramma wasps for decades to
control outdoor pests plaguing cotton and other crops, so the beneficial
insects would be readily available to the pest control industry.
Flinn works in the ARS
Marketing and Production Research Center in Manhattan.
ARS is U.S. Department of
Agriculture's chief scientific research agency.