Changing strategies for sustainable management of cotton pests in sub-Saharan Africa.

摘要

In sub-Saharan Africa, the profitability and sustainability of the cotton crop are key issues for millions of smallholders. In the field of pest management, farmers have to cope with the unsettled impact of an active pest complex. Research has currently not only to make proposals for pest management in a context of insecticide resistance, but also to find how to properly introduce genetically modified cottons. Research is today able to transfer knowledge about pest population dynamics, about the relations between insects and the plants grown in the ecosystem, about morphological or biochemical barriers against cotton diseases and pests and about the thresholds to be used for a rational chemical control. The main problem is for farmers to integrate these results in the management of their cotton crops. They have to use sowing dates, density and fertilizers in order to minimize pest impact. They have to use chemicals with a good knowledge of both their targets and side-effects. Models have an important place in the decision process, as long as they are easy to use and adapted to farmers' needs and constraints. In the new picture of the cotton production chain in Africa, research must be associated not only with the R/D services in cotton companies, but also with emerging farmers' organisations. In the field of varietal improvement, the current evolution is to introduce private companies as seed providers. Competition with national research institutions will be strong. For genetically modified cottons, national research programs leading to the introduction of genes of interest in the local cultivars have to be built. Studies on the long-term impact of the innovations are needed, as much in the agronomic field as in the socio-economic and environmental fields. To reduce pesticide use, it is a necessity to train all the stakeholders for a sound approach of chemicals. The development of decision tools is a priority so that the right product is used at the right time. Sustainability of cotton-based agro-systems can also be solved by the choice given to each farmer to adopt practices adapted to his objectives, needs and constraints. The productivity of the cotton crop is a major concern to reduce competition for land especially where food crops are concerned, and farmers must have access to inputs and credit to manage their crops in order to derive the income they deserve. In the future, farmers' organisations will be key players in the formulation of the problems cotton growers have to face, and they will be involved in a strong partnership with public research in the adoption process of technical innovations..