
Tiny Wasp Runs Sting Operation on Tarnished
Plant BugBy Hank Becker November 19, 1997Quarter-inch-long parasitic wasps
released in New Hampshire seven years ago are multiplying and spreading to
attack tarnished plant bugs. The bugs attack alfalfa, strawberries and other
fruits and vegetables. The female Peristenusdigoneutis wasp stings a young plant bug
nymph and lays an egg inside the hapless host. A few days later, a wasp larva
hatches and begins to eat the nymph from the inside out, killing it in about a
week. In New Hampshire and other northeastern states, tarnished plant bug nymphs
and adults attack alfalfa plants. When the alfalfa is cut for hay, the bugs fly
off to infest nearby fruit and vegetable crops like strawberries, peaches,
apples and beans. The wasp is now killing many plant bugs before they leave the
alfalfa. Future studies will determine if the wasps kill plant bugs infesting
these other crops. Entomologists with the Agricultural
Research Service in Newark, Del., and colleagues at the
University of New Hampshire, Durham, released
3,000 Peristenus wasps into alfalfa fields near the university seven
years ago. UNH workers sampled dozens of fields over several years to collect plant bug
nymphs. They sent the samples to the ARS scientists in Newark for analysis--to
see if the parasites had survived and deposited eggs in the collected plant
bugs. They had. At one farm in the town of Strafford, 35 percent of the
tarnished plant bugs were killed by the parasite. The wasp has now been found in six of New Hampshires 10 counties. It
has survived as far north as the Canadian border near Lake Champlain in New
York. Scientific contact: William H. Day, ARS
Beneficial Insects Research
Laboratory, Newark, DE 19713; phone (302) 731-7330, fax (302) 737-6780,
[email protected];
Alan T. Eaton, Plant Biology
Department, University of New Hampshire, Durham, NH, phone (603) 862-1734, fax
(603) 862-1713, [email protected] U.S. Department of Agriculture | |