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.