Motorised mistblowers: their performance and rationale in developing countries

217 Some of the technical and operational aspects of using motorised mistblowers on tropical crops such as cocoa are described. Mistblowers are often used in centrally coordinated control campaigns in Ghana, with these sprayers currently used for applying pyrethroid, neonicatinoid and remaining stocks of organophosphorus and carbamate insecticides against cocoa mirids (Sahlbergella singularis and Distantiella theobromae). Mistblowers are preferred since cocoa trees in West Africa are often extremely tall, and a high work rate enables timely application. Our current research focuses on optimising delivery systems for alternative microbial control agents (MCAs), such as Beauveria bassiana, and assessing their efficacy. The influence of droplet size on the dose transfer of both chemicals and MCAs to insect pests is discussed, together with the logistics and economics of mistblower use in comparison with manually operated sprayers. . Clearly, research to update cocoa mirid control techniques is needed, but much could be done to improve the implementation of known techniques: using established protocols and equipment specifications.