Development of targeted insecticide treatment for improved storage of maize cobs on traditional platforms in Ghana

Improvements to maize cob storage on farms in the Volta Region of Ghana were investigated with a view to limiting the damage and losses associated with the Larger Grain Borer (Prostephanus truncatus) and weevils (Sitophilus spp). The study was initiated by a survey of those technologies adopted following an earlier project to help farmers protect maize against P. truncatus. The study included farmers’ perceptions of their own storage problems and was designed to provide background information on how farmers might benefit from a novel technique of applying pesticide to only the basal layers of cobs on the platform. Field trials, comparing losses in experimental maize platforms showed that treatment of only the bottom 20% of maize cobs, with Actellic Super (permethrin and pirimiphosmethyl) in dust or emulsion formulation, could give protection that was significantly better than no treatment and not significantly different from full treatment. When combined with placing a plastic sheet over the platform there was a significant reduction in losses while the presence of preharvest infestation resulted in somewhat higher losses. Farmer participatory trials demonstrated that farmers could implement the technique successfully by themselves and subsequent analysis showed that a range of major stakeholders perceived benefits from the method and reaffirmed it as a practical approach. The cost effectiveness of the method was investigated based on assumptions about maize losses and prices. This analysis suggested that targeted treatment is likely to be cost-effective under a wide range of circumstances. However, it was concluded that the safest option for farmers would be to use targeted treatment for those platforms that would be consumed during the course of the year and use full treatment for platforms destined for long-term storage (>6 months). It is suggested that such an approach would widen farmer access to stock protection and improve food security and livelihoods