Functional biodiversity for sustainable management of African rice gall midge in lowland rice-based systems

摘要

The African rice gall midge (AfRGM), Orseolia oryzivora Harris & Gagne (Diptera: Cecidomyiidae) is a serious insect pest of rice in rainfed and irrigated lowland systems in Africa. The larvae are stalk borers of rice at vegetative growth stages and cause rice leaves to grow into tubular galls called 'silver shoots' or 'onion leaves' that prevent panicle from bearing grains. Heavy yield losses (45-80%) due to AfRGM have been reported in farmers' rice crops from endemic locations in Africa. Because ofthis biotic constraint, the intensification practices of lowland rice farmers are unsustainable. There is an urgent need to prevent the pest-induced crop losses and ensure food security and poverty reduction in Africa. Amongst IPM approaches being explored against AfRGM is the integration of available midge-tolerant varieties with natural biological control through habitat management. Understanding inter-specific relationships in agro-ecosystems and the roles these species play in crop protection are essential to the development of sustainable IPM strategies. Pending availability of high yielding rice varieties with durable resistance to AfRGM (Nwilene et al., 2002), this study explored biodiversity as a functional principle of pest (AfRGM) management.