IITA IPM project 02: Combating the cowpea pod borer Maruca vitrata by integrating habitat management and biological control.

Duration: 2 years (2003 to 2005)

Purpose: To assess the feasibility of an integrated plant health management strategy, based on the improved understanding and use of resistant varieties, intercropping patterns, trap and non-host crops, and more efficient natural enemies for the control of M. vitrata on cowpea by small-scale farmers at pilot sites in Northern Nigeria.

Background/description: In the moist areas further south, M. vitrata has been observed to pass the dry season feeding and reproducing on a wide range of alternative host plants. Among these host plants there might be some which can act as a trap crop for oviposition, thereby diverting the pest population from the cowpea crop. Also, it is known from maize ecosystems in Kenya that some plants are natural repellents of stemborer moths, being at the same time a valuable source of fodder. This system could be adapted to conditions in northern Nigeria, e.g. by using fodder plants suitable for small ruminants. In addition, those plants could be selected also for their ability in stimulating suicidal germination of major parasitic weeds in the system, Striga hermonthica on sorghum and maize and Striga gesnerioides on cowpea. In addition to combating M. vitrata in cowpea fields, control strategies can be targeted to areas where alternative host plants are abundant and constitute a major factor influencing the dynamics of M. vitrata populations. In this case, the objective would be to reduce overall population pressure, which could be done by the introduction of presumed more efficient natural enemies such as the parasitoids Phanerotoma philippinensis and Bassus javanicus observed in Southeast Asia.

Agroecozone(s) and location(s): Northern Guinea Savanna in Nigeria

Expected outputs: a) Wild and cultivated host plants for M. vitrata that are preferred over cowpea by ovipositing moths are selected; b) Wild and cultivated fodder plants with repellent activity against M. vitrata, and with additional capability of suicidal germination of cereals and/or cowpea Striga are identified; c) Better performing exotic natural enemies from tropical Asia are identified and tested at BCCA, and their interactions with the above resistant cultivars and host plants are assessed.

Potential impact and beneficiaries: Cowpea farmers will be the primary beneficiaries of the immediate results from the release of biological control organisms by obtaining higher yields through lower pest densities. These biocontrol organisms are expected to establish in the immediate release areas, and subsequently expand into other areas where the host is present, so no other action is required for further implementation. In addition, farmers will also profit from higher yield obtained by the integration of habitat managements options (trap/non-host plants) into best bets.

Partners: a) Amadu Bello University, Zaria; b) AVRDC

Development investor(s): Gatsby Charitable Foundation

IITA contact person(s)/principal investigator(s): Manu Tamo M.Tamo@cgiar.org and B.B Singh IITA-KANO@cgiar.org website http://www.iita.org