Managing chickpea pod borer with entomopathogenic nematodes

Helicoverpa armigera (Hüb.) commonly known as pod borer or bollworm is the only pest which comes regularly on chickpea, an important pulse crop grown in Indian Sub Continent. Use of biorationals (nematodes and botanicals) is gaining momentum in view of ill effects of insecticides on environment and non target organisms including human beings. Lethal concentration of 145 infective juveniles (IJs) and 195 IJs of Heterorhabditis indica was fixed for third and fourth instar larva, respectively. Nematode survivability enhances when applied along with antidessicant, glycerin (0.1%). In combination studies, H. indica recorded the highest mortality (60-100%) when combined with botanicals compared to alone treatments which indicate the synergistic action against test larvae. In the field trial, sequential application of H. indica + P. juliflora (1 lakh IJs/l + 10%) recorded highest larval reduction (23.47%), minimum pod yield (11.27%) and highest seed yield (19.24 q/ha). The same combination fetched the highest net returns of Rs. 24,474/ ha with an incremental cost benefit ratio of 1:7.34 which is on par with insecticidal spray (Rs. 24,818/ha and 1:11.6).