Fruits, 2013, vol. 68, p. 83–93
© 2013 Cirad/EDP Sciences
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-onstump
(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.