Integrated pest management of borers of cowpea and beans

Abstract

Cowpea, Vigna unguiculata (Walp) and beans, Phaseolus vulgaris are attacked by several insect pests worldwide. The pests include economically important borers, the control of which often requires the use of more than one tactic. In Africa, the major borer species of cowpea is Manica vitrata Fab. (syn. M. testulalis [Geyer]); in Southeast Asia and eastern Africa the beanfly or bean stem maggot complex, Ophiomyia spp., is important on beans. The bean borer, Etiella zinckenella (Treitschke), is also of considerable importance in Asia. In South America Epinotia apotema (Wals) and Cydia fabivora (Meyrick) are the most important borers on beans, while Helicoverpa armigera (Hubner) and M. vitrata to a lesser degree are important on beans in some parts of Africa. Presently, only chemical control provides complete protection against crop borers, but despite its usually favourable cost-to-benefit ratio, insecticide use is not a sustainable option. Other tactics such as cultural control, host plant resistance and the use of beneficial organisms are more dependable in the long-term. They form the core of the new vision for environmentally friendly pest management, or bio-intensive pest management, which minimises the use of synthetic insecticides. In recent times, research efforts directed at these measures have been intensified. This paper discusses the various interventions and presents different IPM models on how they can be combined to optimise the control of borers. Suggestions are made on the future outlook of IPM on cowpea and beans.