EFFICACY OF LONG-LASTING INSECTICIDAL NET (LLIN) IN CONTROLLING TOBACCO BEETLE (LASIODERMA SERRICORNE) IN MALAWI

The tobacco beetle, Lasioderma serricorne, is a serious insect pest of cured tobacco in Malawi. Fumigation with phosphine is the most common method of control for infested tobacco; however, fumigation has no residual effect and repeated fumigation is required in circumstances where reinfestation easily occurs. Refumigation of tobacco is costly and increases the chances of beetle resistance to phosphine. Experiments were conducted in tobacco warehouses in Lilongwe, Malawi to assess the efficacy of long-lasting insecticidal net (LLIN) combined with phosphine fumigation against the tobacco beetle. The adult beetles caught in pheromone traps placed on tobacco stacks covered with LLIN during a 13-week storage period were always significantly fewer than those without LLIN (untreated control). When tobacco stacks were covered with LLIN after fumigation with phosphine, the initial infestation is expected to be zero; the trap catches remained zero for the whole storage period in most cases. These results suggest t...