Scheepens, M.H.M., Department of Entomology, Institute of Plant Protection, Agricultural Research Organization, Bet Dagan 50-250, Israel
Wysoki, M., Department of Entomology, Institute of Plant Protection, Agricultural Research Organization, Bet Dagan 50-250, Israel

The nuclear polyhedrosis virus (AcMNPV) isolated from Autographa californica (Noctuidae) was bioassayed against five lepidopteran species. Heliothis peltigera (Noctuidae) was very sensitive to AcMNPV. A concentration of 417 PIBs/mm2 diet killed all 10-mm larvae within 1 week. Heliothis armigera (Noctuidae) also proved to be sensitive. Between 8 and 36% of virus-treated 10-mm larvae developed into adults, compared with 64 and 74% of the controls. Spodoptera littoralis (Noctuidae) was completely insensitive. Boarmia selenaria (Geometridae) showed a low response: 15 days after feeding 10-mm larvae with a concentration of 29,252 PIBs/mm2, 36% had died. Ephestia cautella (Pyralidae) was affected to a low extent by AcMNPV: up to 38% of 5-mm larvae fed with polyhedra died after 37 days, and even fewer 10-mm larvae were affected. © 1989.