Boric acid concentrations (0.02,0.03,0.045,0.067 and 0.101 g/100 ml of diet) were evaluated in combination with the Anticarsia gemmatalis Hüb. nuclear polyhedrosis virus (AgNPV) for enhanced virali activity against the insect. Seven days after inoculation, the median lethal concentration (LC50) was 1.52 x 10(5) for the AgNPV alone and 7.95 x 10² for the NPV mixed with 0.045g of boric acid/100 ml of diet. At subsequent evaluation dates (9,11 and 14 days after inoculation) LC50's for NPV+boric acid were ca. 4x lower than those observed for the NPV alone. The median lethal time (LT50) was 13.6 days when the NPV was used alone, while, when in mixture with increasing concentrations of boric acid, LT50 values ranged from 13.7 days (boric acid at 0.02g/100 ml of diet) to 7.4 days (boric acid at 0.101 g/ml of diet). Therefore, boric acid added to the AgNPV significantly increased A. gemmatalis larval mortality and shortened mortality time by the pathogen.
Insecta; velvetbean caterpiliar; biological control; baculovirus
