Effect of different Sowing Windows on Major Insect Pests and Host Plant Resistance to Pod Borer, Helicoverpa armigera in Pigeonpea (Cajanus cajan (L.) Millsp.)

Effect of sowing dates, climatic variables on major insect pests population, and host plant resistance with special reference to pod borer Helicoverpa armigera (Hubner) in pigeon pea (Cajanus cajan (L.) ecosystem was studied on two cultivars namely, ICPL 87 and ICPL 88039. The insect pest population on two cultivars differed significantly across sowing dates. ICPL 87 was most vulnerable to insect pests as \nit suffered more damage by the pod borer H. armigera, pod sucking bugs (Clavigralla tomentosicollis Stal.) than ICPL 88039. The maximum leaf/pod feeding insect population was recorded on first sowing and then gradually decline for the rest of the plantings. Maximum H. armigera egg population exhibited 21.10 on ICPL 87 in first sowing and at least 1.23 on ICPL 88039 in sixth sowing. Web forming insect pests Maruca virata (3.95) and leaf webber (4.66) weremaximum recorded on ICPL 88039 in second and first planting respectively. The leaf feeding beetle was recorded highest 6.29(ICPL 87) in the third planting. Amid two cultivars maximum insect-pests population was recorded on ICPL 87 when compared to ICPL 88039 except web forming insect Maruca and leaf webber due to its indeterminate genotypic character of ICPL 88039. Between the two genotypes, the sucking pests more preferred to ICPL 87 when compared ICPL 88039. Maximum jassids were recorded 12.76 and 8.38 (ICPL 87) in fourth sowing and third sowing respectively. It was observed that highest spider population recorded 2.23(ICPL 88039) in \nfirst and second sowing. Ladybird beetle Coccinella transvasalis population recorded a maximum 8.52 (ICPL 87). The leaf webber (r= 0.449**) and pod bug (r= 0.421**) showed a highly significant positive correlation with maximum temperature and H. armigera larvae population exhibited highly significant positive correlation with minimum temperature (r= 0.491**) and morning relative humidity (r= 0.528**). Solar radiation also exhibited and showed a significant positive correlation with leaf webber (r= 533**).