AREA-WIDE MANAGEMENT OF COTTON BOLLWORM AND TOBACCO BUDWORM (LEPIDOPTERA, NOCTUIDAE) THROUGH APPLICATION OF A NUCLEAR POLYHEDROSIS-VIRUS ONEARLY-SEASON ALTERNATE HOSTS

A field trial was done in 1990 using aircraft to treat all vegetation in a 259-km2 area with the nuclear polyhedrosis virus from the cotton bollworm, Helicoverpa zea (Boddie), to control the first generation of bollworm and tobacco budworm, Heliothis virescens (F.). Bioassays of early-season hosts from the treated area indicated that almost-equal-t o 12% as much virus and 8% as many spray droplets were deposited on th e plants compared with results of a previous small-area study. Althoug h the area-wide viral coverage on target plants was inadequate, result s of pheromone trap data indicated that populations of emerging adults were reduced 19-38% compared with adults from untreated areas. The vi rus remained active on the host plants (i.e., 47% of the original viru s activity remained 9 d after treatment). In cage testing areas where bioassays indicated that somewhat more virus was deposited, we detecte d a 41% average reduction in adult emergence in cages placed over trea ted wild hosts compared with untreated areas.