A farmer participatory research approach to assess the effectiveness of field sanitation and regular trapping on banana weevil populations.

Introduction. Small-scale banana producers in Tanzania are facing constraints caused by the destructive activities of the banana weevil (Cosmopolites sordidus Germar). Many currently used methods of addressing the problem are ineffective or too expensive for local farmers to implement. Materials and methods. A combination of two integrated pest management (IPM) tools (regular trapping in combination with field sanitation) was tested at two farmer-managed sites (Bujela and Kyimo) and one researcher-managed site (SUA-Morogoro). Treated areas were surrounded by untreated control areas where no trapping and limited sanitation was done. Changes in population densities were estimated by the mark-recapture procedure and the Lincoln index. Results and discussion. After eight months, weevil populations in the cleaned and trapped areas had been reduced by 33% (Bujela), 33% (Kyimo) and 74% (SUA). The change in population sizes in the control areas differed greatly, possibly due to discrepancies in field management between farmers’ and researchers’ practice. Trap types, areas and sites affected the number of weevils captured. Disc-on-stump (DOS) traps captured more weevils than corm disc (CD) and pseudostem (PS) traps. Weevils responded more strongly to traps in the clean area at SUA compared with the other two sites, probably because the more rigid sanitation practices at SUA meant that volatiles from the traps were less likely to be masked by volatiles from surrounding residues. Conclusion. Regular trapping with field sanitation can greatly reduce populations of banana weevils, but strict adherence to method execution is required in order to gain favourable results. [ABSTRACT FROM AUTHOR]