Efficacy of nuclear polyhedrosis virus against Helicoverpa armigera (Hbn.) on Helicoverpa-resistant and susceptible varieties of chickpea

Abstract

Helicoverpa armigera (Hbn.) larval mortality due to nuclear polyhedrosis virus (NPV) was significantly higher on Helicoverpa-susceptible varieties (Shoba and Annigeri) than on the resistant accessions (ICC 506 and ICC 10817). Mortality was at an intermediate level on Co2, the moderately susceptible variety. Leaf consumption was also significantly higher on the susceptible varieties and was positively correlated with larval mortality rates. Probit analysis showed that the virus also recorded a shorter LT 50 on the susceptible than on the tolerant or resistant varieties. Results of a field trial showed that control of H. armigera with NPV was significant on the highly susceptible (Shoba) or moderately susceptible (Co2) varieties. On the tolerant variety (ICC 506), even though virus application significantly reduced the larval numbers, pod damage and yield did not differ significantly from those of the control.