Insect pest succession and screening for spotted pod borer tolerance in short duration pigeonpea

Pigeonpea (Cajanus cajan L) is a major legume crop cultivated in India and insect pests inflict heavy yield loss. The insect pest succession and population dynamics varies according to agro-climatic zones. In Kanpur, six insect pests viz., leaf webber, blister beetle, spotted pod borer, pod bugs, gram pod borer and pod fly infested ICPL 67B during Kharif 2013. Spotted pod borer (SPB), Maruca vitrata Fabricius is a serious pest that causes severe flower and pod damage. Hence in the present study 30 different pigeonpea genotypes were screened under field conditions against SPB. The larval webbing per plant varied from 0.13 (JA 4) to 10.13 (MN 5), while the pod evaluation index ranged from 1.12 (ICPL 88039) to 66.08 (JA 4). Among the 3 morphological parameters studied, inflorescence stalk length was found to be negatively correlated with spotted pod borer infestation. The results of field infestation and morphological parameter correlation revealed JA 4 as a SPB resistant genotype. Further confirmatory tests like no choice assay coupled with biochemical and biophysical analysis may reveal the mechanism of resistance in this genotype.