Submitted to: International Plant Protection Congress
Publication Type: Proceedings
Publication Acceptance Date: 4/10/2004
Publication Date: 5/11/2004
Citation: Fuester, R. W.; W. H. Day, C. H. Pickett, & K. A. Hoelmer. 2004. Introduction, release, and establishment of European PERISTENUS spp. on mirid plant pests in North America. Proc. 15th Internat. Plant Protection Congress, Beijing, China, May 11-16, 2004. p. 132 Interpretive Summary: The tarnished plant bug and the western tarnished plant bug, a close relative, injure fruits, vegetables, cotton, reforestation seedlings and many seed crops. Economic losses approximate $2.1 billion per year. The alfalfa plant bug, an introduced species from Eurasia, infests alfalfa in the eastern U.S. and Canada. Native natural enemies attacking these pests are ineffective, attacking only a small proportion of immature stages (nymphs). Previous studies by ARS scientists and cooperators in Europe indicated that the nymphs of the European tarnished plant bug and alfalfa plant bug sustain substantial levels of parasitism there. The natural enemies, parasitic wasps that are harmless to humans, run down the nymphs and lay an egg within. The egg hatches into a grub, that feeds in the nymph, emerges when full grown (killing the host) and spins a cocoon in the soil. Five species of wasps were imported from Europe, three for control of tarnished plant bug and western tarnished plant bug and three for control of alfalfa plant bug (one species attacked all three pest species) and released in New Jersey, Delaware and (more recently) California. One of the species brought about control of the tarnished plant bug on alfalfa in the northeastern U.S., where recent work suggests that it is decreasing damage by the pest in strawberries and apples. In 1998, this species and another, common in southern Europe, were released and became established in California. Though it is too early to claim successful biocontrol, sizeable increases in parasitism of western tarnished plant bug were noted in 2000-2002. Two of the species released against alfalfa plant bug failed to become established, but a third species, which has only females, was recovered at the release site. Further evaluation is in progress.
Technical Abstract: The tarnished plant bug, Lygus lineolaris (Palisot), and western tarnished plant bug, L. hesperus Knight, important pests of numerous crops, are widely distributed east and west of the Rocky Mountains, respectively. The alfalfa plant bug, Adelphocoris lineolatus Goeze, a Palearctic species, infests alfalfa in the eastern U.S. and Canada. Native natural enemies attacking these pests are ineffective. Nymphal parasitoids of L. rugulipennis and A. lineolatus were imported from Europe. Candidates for control of the Lygus pests included two polyvoltine species, Peristenus digoneutis (Loan) and P. stygicus (Loan), and a univoltine species, P. rubricollis (Thomson). The latter and P. adelphocoridis Loan, another univoltine species, were candidates for control of A. lineolatus. Although earlier attempts to establish parasitoids were unsuccessful, intensive efforts in the 1980's resulted in the establishment of P. digoneutis in New Jersey. Successful biocontrol of L. lineolaris in alfalfa was achieved, and P. digoneutis had spread throughout much of the northeastern U.S. by 2000. Recent studies suggest that its action decreases damage by L. lineolaris in apples and strawberries. Beginning in 1998, P. stygicus and P. digoneutis were released in California, where both species became established. Though it is too early to claim successful biocontrol, substantial annual increases in parasitism were noted in 2000 2002. Both P. rubricollis and P. adelphocoridis were released against A. lineolatus in Delaware, but neither became established. Several years later, P. conradi Marsh, a thelytokous species closely resembling P. rubricollis (and presumed to have been released with it) was recovered at the release site.