Wasp That Attacks Western Plant
Bug May Control Its Mid-Atlantic Cousin
By Hank Becker
March 8, 2000
A new species of parasitic wasp
discovered in Idaho attacking the western tarnished plant bug may help control
a related pest species in the mid-Atlantic states.
Much of the seed needed to grow many important domestic crops is produced in
the northwestern United States. Each year, the western tarnished plant bug
(WTPB), Lygus hesperus, and its cousins suck the sap from flowers, young fruits
and seeds. To prevent serious reductions in quantity and quality of the seed
crops, growers spend tens of millions to control this major pest.
An ARS researcher at the Beneficial Insects Introduction
Research Laboratory, Newark, Delaware, cooperating with a
University of Idaho-Parma Moscow
scientist, discovered a previously unknown species of parasitic wasp attacking
the WTPB in alfalfa seed fields in southwestern Idaho.
Over three WTPB generations in 1997 and 1998, the wasp killed 44 to 81
percent of the pests. Further research in Idaho is warranted to determine if
this degree of parasitism is sufficient to reduce the need for insecticides.
After a retired ARS taxonomist verified the ARS entomologist's determination
that the Idaho parasite was a new wasp species, a cooperating
University of Wyoming-Laramie scientist
described it as Peristenus howardi Shaw. P. howardi was later discovered in
eastern Washington state and may also be in Oregon.
In ARS laboratory tests, the new wasp readily parasitized the tarnished
plant bug (TPB), Lygus lineolaris--a close relative of the WTPB. The TPB is an
important pest of many crops in the eastern half of the United States but has
no significant natural enemies south of New York.
A European parasite, Peristenus digoneutis Loan, established by the ARS
Newark lab, is a promising biological control agent in New England, New York,
northern Pennsylvania and New Jersey.
P. howardi was recently released under permit in Delaware, with the goal of
permanently establishing it to reduce TPB damage to fruits and vegetables in
the mid-Atlantic states.
ARS is the chief research agency of the U.S.
Department of Agriculture.
Scientific contact: William H. Day, ARS Beneficial Insects
Introduction Research Laboratory, Newark, Del.; phone (302) 731-7330, ext. 24,
fax (302) &37-6780, email@example.com.