PLANT PROTEINASE-INHIBITORS ARE POTENTIAL ANTICEREAL APHID COMPOUNDS

Trials were conducted to identify new compounds that may be useful in the control of cereal aphids on wheat, Triticum aestivum (L.). Five pl ant proteinase inhibitors were tested for their ability to control 3 s pecies of cereal aphids in feeding trials. The proteinase inhibitors w ere tested against the Russian wheat aphid, Diuraphis noxia (Mordvilko ), the greenbug, Schizaphis graminum (Rondani), and the bird cherry-oa t aphid, Rhoalosiphum padi (L.). Two of these compounds, potato protei nase inhibitors I and Il, increased mortality among late instar aphids and reduced production of nymphs in feeding trials. Potato carboxypep tidase inhibitor and soybean trypsin inhibitor showed variable effects ranging from significant to nonsignificant abiosis, depending on the species of aphid examined. The lima bean proteinase inhibitor showed l ittle effect on any of the 3 species. Though the effectiveness of the inhibitors varied, it appears that the proteinase inhibitors from pota to are potentially effective proteins for the control of these species .