| In Germany and Switzerland observational field studies were made on species of Peristenus Foerster parasitoids and their mirid hosts, from 1998--2000. The intent of this research was to provide new ecological information which could be used to evaluate the potential of selected European Peristenus species as biological control agents for pest Lygus (Hahn) and Adelphocoris lineolatus (Goeze) in North America.;The following plant bug species, L. rugulipennis Poppius, L. pratensis (L.) and A. lineolatus, were collected in fields of alfalfa, red clover, mixed clover, asparagus, barley, rape seed and mustard, to determine the host's phenology and field levels of parasitism. Plant bug nymphs that were collected were used to compare the detection of parasitoids in nymphs by rearing and dissection methods. In this study, rearing was found to be more accurate in detecting parasitoids. Parasitoid cocoons obtained from the rearing of plant bug nymphs were monitored for adult parasitoid emergence. All parasitoid adults were preserved and identified. Information on the emergence patterns for Peristenus digoneutis Loan, Peristenus stygicus Loan and Peristenus rubricollis (Thomson) is presented. Emergence information is also presented for other Peristenus, Leiophron, and Mesochorus parasitoid species. Surveys were carried out in Germany and Switzerland in many different habitats, ranging from agricultural fields to mountain meadows, to collect mirids to rear for parasitoids to investigate the ecological host range of Peristenus species. |
