Raising wasps that cotton to boll weevils.

Twice a week, beginning May 18, entomologists have carted quart-size cardboard containers to a 1-acre cotton plot. As the scientists open the cartons, out fly 400 aggressive female wasps. Each has a single purpose -- finding young boll weevils beside which to lay her eggs. To ensure that the tasty weevils stay put long enough to nourish her young, each wasp first paralyzes the weevil larvae -- a move that eventually kills the young beetles.

A few growers release wasps and other insects for natural pest control, but these beneficial insects are raised on their natural prey, notes Edgar G. King, director of the Agricultural Research Service (ARS) subtropical laboratory in Weslaco, Texas. Indeed, his lab has been raising wasps on weevils. But the costs of rearing both predator and prey have limited adoption of biological pest control by U.S. agriculture. King hopes to change that.

The 3/8-inch Catolaccus grandis wasps his group began freeing last week in Monte Alto, Texas, represent the first release of beneficial insects reared on an artificial diet devoid of insects. And as of May 23, 3 days after the second release, King reports that sampling data indicate "we're approaching 70 percent mortality" of the weevils susceptible to wasp attack.

Guadelupe Rojas led the team's program to develop the new diet -- a custom blend of 57 different materials, including vitamins, fats, amino acids, salts, sugar, and cholesterol. Unexpectedly, the golden gel provides some chemical cue that encourages mother wasps to preferentially lay eggs that will become females -- the weevil slayers.

"Based on calculations we've made," King says, the artificial diet "might bring down costs [for biocontrol of cotton] from $300 an acre to just $30."

The key to keeping costs low will be automated wasp rearing. In what may prove the ultimate offshoot of Project Plowshare -- a federal program begun in 1959 to develop peaceful usesfor nuclear technology -- ARS is turning to the Energy Department's Kansas City, Mo., plant. Renowned for producing all the non-nuclear components of nuclear weapons, this plant is currently designing eight different prototype machines for everything from fabricating wasp food and plastic meal "cups" to gently moving individual wasp eggs and tracking batches of hatched insects.

Acknowledges Kathy Palamara of AlliedSignal, the company that manages the plant, "It sounds unusual, but it's really a good fit for us in terms of exercising our skills in mechanical, chemical, electrical, plastics, and software engineering."