Participatory development of a biological control strategy of the variegated grasshopper in the humid tropics in West Africa uri icon

abstract

  • The results of a participatory rural appraisal (PRA) in 3 villages in the Couffo district of Benin show that the variegated grasshopper Zonocerus variegatus L. is a major, but recent, crop pest. Farmers' knowledge of grasshopper biology is limited and they have not yet developed indigenous control methods. Villagers were keen to collaborate in a participatory research, testing alternative control methods. A demonstration of biological control of grasshoppers was organized, followed by the training of a group of six farmers per village-the village brigade, who will be in charge of grasshopper control in their village. After the training, where grasshopper biology and the advantages and disadvantages of different control options were discussed, it was agreed to test a biological pesticide, an oil-based formulation of the entomopathogenic fungus Metarhizium anisopliae var. acridum, in a participatory research program. The village brigades chose to test two different strategies: preventive control by treating the young larval stages and curative control by treating adult grasshoppers, with two different sprayers (flit gun and spinning-disc sprayer). Both strategies were tested at three different doses (2, 20 and 50 g of spores/ha). Results show that the dose can be reduced to 20 g/ha without loss of efficacy, so the cost of the treatment (estimated at $20/100g or $4/ha) is within the farmer's reach. Participatory testing also revealed that treating the uncultivated areas is not a practical strategy. Finally, although battery -powered spinning-disc sprayers are more expensive than the hand-powered flit gun sprayers, their higher efficacy justifies the extra expense. The villagers proposed that grasshopper biological control be organized by village brigades, in close collaboration with the village association of cotton growers, who will provide credit. For the 1998-1999 season, this strategy was proposed and accepted in IS new villages, and each village organized a brigade, trained by the project. Women, who generally manage their own fields, preferred a separate brigade, and three female brigades have been trained so far. (C) 2002 Elsevier Science Ltd. All rights reserved.

publication date

  • 2002
  • 2002