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New Diet Could Help Trim Crop Pest PopulationsBy Jesús García
May 16, 2000
Agricultural Research Service scientists have now applied for a patent on a new insect diet that will make plant bugs and other crop pests unwitting accomplices to their own destruction.
The key to mass-rearing these ravenous insects in sufficient numbers is developing a replacement for the plants they feed on. Without these special diets, the rearing of these insects becomes cost prohibitive.
The new diet, which consists of cooked chicken eggs, lima bean meal, wheat germ, soy flour, yeast, sugar, vitamins and preservatives, was developed by scientists at ARS Biological Control and Mass Rearing Research Unit in Mississippi State, Miss. This diet enables researchers to propagate destructive plant bugs as hosts for the production of parasitoids that may eventually help reduce insect pest numbers in the wild.
One of these pests, the western tarnished plant bug, Lygus hesperus, accounted for about $71 million worth of cotton crop losses in 1998.
One parasitoid, a tiny wasp called Amaphes iole, deposits its own egg into Lygus bug eggs, where it develops into an adult while consuming the Lygus eggs contents. Once the adult wasp emerges, it is ready to mate. Any female offspring is capable of parasitizing up to 60 Lygus eggs in its 2-4 days of life as an adult.
Two other wasps, Peristenus spp. and Leiophron uniformis, deposit their eggs inside Lygus nymphs, where they commence to feed. When the parasitoids reach their prepupal stage, they chew their way out of their devastated hosts.
The new diet-fed insects are also used for research on sterile release programs which had never before included Lygus bugs because they could not be reared in sufficient numbers. Sterilized plant bugs reared on the diet may mate and produce sterile eggs in the wild.
Most important, the new diet has been found to be an inexpensive and effective way to mass rear insect pests and their natural enemies for biologically based pest management.
This technology enhances the agricultural communitys ability to mass-produce natural enemies of pests and decreases its dependence on chemicals.
ARS is the chief research arm of the USDA.