부산대학교 도서관

In the climate change context, ICRISAT is promoting water-saving cropping systems mixing food and horticultural crops for the Sudano-Sahelian zone of Western Africa. ICRISAT's partners in Niger (CIRAD, the University of Niamey and INRAN) are seeking ways to minimize the impact of crop pests in these systems, using the agroecological approach. Following encouraging earlier results, agroecological management options were further investigated in 2010 for the major pests of okra, jujube tree and watermelon, the major horticultural crops in the water harvesting-based Bio-Reclamation of Degraded Lands (BDL) and Dryland Eco-Farm (DEF) systems. Pigeon pea was evaluated as a trap crop for regulating infestation of okra by the fruit worm Helicoverpa armigera in a design with four treatments (unbordered cypermethrin-sprayed and unsprayed controls, and two pigeon pea-bordered unsprayed treatments, with an early and an extra-early cultivar). On the other hand, the foliage of 4 trees in a jujube orchard was sprayed with GF-120 (mixture of food attractant and biological insecticide) with 2 trees remaining unsprayed. White linen sheets were placed under the sprayed trees, in view of collecting the flies that would have ingested the bait, and ripe jujube fruits were harvested and weighed. Results on okra suggested a new ''top-down" regulation process, further to the mere "bottom-up" trap-cropping effect, which questions the relevance of both attempting to reinforce the "pull" trap-cropping effect with a ''push"' effect using insect-repellent sprays on the main okra crop, and playing on a barrier effect of the perirneter trap crop against piercing-sucking homopteran pests. Results on jujube suggested that GF-120 could be used both as a repellent to protect jujube trees from the fruit fly Carpomya incompleta, and as an attractant to protect water melon, which is part of the DEF system, from Dacus spp., thus killing two birds with one stone.