Efficacy of fish- and hydramethylnon-based baits for conservation of the African weaver ant Oecophylla longinoda (Hymenoptera: Formicidae) during cashew off-seasons in Tanzania

The efficacy of fish- and hydramethylnon-based baits for conservation of the African weaver ant (AWA) Oecophylla longinoda Latreille was evaluated at orchards in Bagamoyo and Mkuranga districts, Coast region of Tanzania, during the cashew off seasons in 2011 and 2012. The baits were applied at monthly intervals; the dynamics of AWA were monitored by counting the number of leaf nests/tree and the colonization trails on main branches. The numbers of leaf nests recorded before baiting ranged between 3.5 and 5.3 and were not significantly different at both sites and in both seasons; after baiting, they ranged between 3.2 and 11.6 at Bagamoyo and between 3.0 and 10.2 at Mkuranga. The colonization of AWA trails recorded before baiting was also not significantly different at both sites and in both seasons and ranged between 37.9 and 50.0%; after baiting, this ranged between 35.9 and 75.1% at Bagamoyo and between 34.6 and 79.2% at Mkuranga. The provision of fish- and hydramethylnon-based baits can effectively contribute to the conservation of AWA during the cashew off-seasons. The fish based bait is cheaper and more easily affordable by local farmers and can, therefore, be used as an alternative diet for AWA at this tim