Integrated Pest Management in Pigeonpea: Progress and Prospects

Pigeonpea is one of the world's most important grain legume crops. Mostly grown and consumed in India, where it is a staple food, pigeonpea production also occurs elsewhere in Asia, Africa, Latin America and Australia. Despite widespread cultivation and staple food status, pigeonpea yields have barely increased over the last half century. The prevalence and severity of insect pests present major constraints to increasing pigeonpea yields. Two of the most significant pests of pigeonpea are the lepidopteran ‘pod-borers’–Helicoverpa armigera and Maruca vitrata. The pod fly (Melanagromyza obtusa) and several species of pod-feeding Hemiptera are also regular pests, and numerous other minor or sporadic pests have been recorded throughout the cultivated distribution of the crop. Current pigeonpea pest management practices rely heavily on the application of synthetic insecticides. Most research has focused on the management of H. armigera, M. vitrata and M. obtusa due to their damaging feeding behaviour, and the propensity of H. armigera to evolve resistance to synthetic insecticides. Not surprisingly, pest management in pigeonpea is largely based around these three major pests, particularly the lepidopteran pod-borers which appear to be more damaging to modern short-duration cultivars than to older cultivars. A large amount of research has attempted to develop pigeonpea cultivars with conventional host-plant resistance to pod-borers and pod fly, but with limited success. Future pigeonpea pest management research should take a more integrated approach, exploring underexamined areas such as: understanding how modern pigeonpea varieties and traditional landraces respond to pest herbivory, identifying what cultural control methods are available to smallholder farmers, and investigating how biological control can be incorporated into management practices. Future research has the potential to develop IPM strategies in pigeonpea and provide farmers with an alternative to an unsustainable dependence on synthetic insecticides.