Estimation of production losses caused by the coffee berry borer (Coleoptera: Scolytidae) and calculation of an economic damage threshold in Togolese coffee plots

The coffee berry borer, #Hypothenemus hampei# (Ferrari) (Coleoptera: Scolytidae), which exists in all coffee producing zones, is a major pest. The seriousness of this scolytid was assessed in Togolese plots spread over five agroclimatic zones, by determining the attack rate from a sample of coffee trees. The work was carried out over 2 yr and revealed that weight losses were proportional to the attack rates. The average infestation rates were 5.64% in the first year and 6.36% in the second year, while total production losses amounted to 2.60% and 3.18%, respectively, for the same periods. Generally speaking, attack rates in the plots were low and varied considerably within a given zone. Plantations located on plateau were more severely attacked than those in the plains. A relationship was established between total losses and the cost of insecticide treatment; this relationship was used to calculate an economic damage threshold beyond which control proves to be cost effective. (Résumé d'auteur