Rebounding Ability of Weaver Ants, Oecophylla longinoda Latreille (Hymenoptera: Formicidae) in Cashew Farming Systems in Tanzania

Abstract

AbstractThe African Weaver antOecophylla longinodaholds a potential of being a vital component in Integrated Pest Management (IPM) programs. However, its exploitation in cashew production systems in Tanzania which relies heavily on the use of synthetic insecticides such as Lambda cyhalothrin for the control of cashew bugs (Helopeltisspp.) had been uncertain. This study examined the possibility ofO. longinodarebounding back after spraying Lamda cyhalothrin to control insect pests during cashew fruiting season. The population abundance ofO. longinodaand their predation efficiency onHelopeltisspp was determined. The study findings suggest that two to three spraying regimes of the insecticide significantly (P<0.001) reducesO. longinodapopulation abundances. The averageO. longinodapopulation declined from a range of 201-500 (average 350.5 insects) per cashew tree to 21-50 (average 35.5 insects) per tree. However, we recorded a quick recovery ofO. longinodapopulation of up to >500 insects per tree (score index 5) when favourable conditions were restored immediately after the fruiting season. On predation efficiency,O. longidodasignificantly (P<0.001) performed equally to Lambda cyhalothrine in reducingHelopeltisspp. Thus, under suitable conditions,O. longinodahas ability to quickly build up to high populations and adequately suppresses the cashew pests. Conclusively, the present study indicated that,O. longinodaas the predator holds great potential in transforming from conventional to organic cashew production system in Tanzania.