Spraying insecticides early in the crop cycle are most likely to kill off the natural enemies and may not be economical. The policy by some governments to give away pesticides to maize farmers to combat FAW or to organize spraying squads may be starting smallholder maize farmers on a pesticide treadmill that may well have negative impacts in the medium term.
Effectiveness of insecticides against FAW also greatly depends on the application technique, dose and formulation. Once the FAW is down in the whorl, the insecticides must reach them there. Spraying with backpack sprayers or through aerial spraying without delivering material directly into the whorl is often ineffective.
Cost of pesticides. The vast majority of maize smallholder farmers in Sub-Saharan Africa do not use pesticides on maize. Farmers consume a part of the maize they produce, and those who sell maize to markets often receive a low price. Spraying insecticides several times can dramatically increase the costs of production, making the maize economically unviable.
