Estimate of cotton production losses caused by pests in Chad.
Cotton production losses caused by pests (including Helicoverpa armigera, Diparopsis watersi, Pectinophora gossypiella and Earias spp.) were assessed at 2 experimental stations in Chad using plots with different levels of phytosanitary protection under excellent cultural conditions. The average production loss with no insecticidal protection was estimated to be 50% of the potential production. No correlation was noted between the annual levels of larvae of the main pests and production losses. A regression model was designed to estimate the gain resulting from the recommended programme: the parameters were sowing date and the types of products applied. An average of 75% of potential production can be achieved by application of the recommended treatment programme. However, the results for on-farm conditions may be different.