Impact of Coelaenomenodera lameensis (Coleoptera, Chrysomelidae: Hispinae) on the Production of Oil palm Plantations at Different Age Groups

Coelaenomenodera lameensis is an oil palm leaf miner. This insect pest causes extensive damage to palm trees in production. To take good measures to protect palm trees against this pest, it is important to know beforehand, its real impact on production. For this, a study was carried out over 5 consecutive years (January 2015 to December 2019) on production plots of the La Mé station of the National Agronomic Research Center. These plots, with an area of between 1 and 3 ha, were divided into 4 categories according to age (8 to 20 years old; 21 to 35 years old; 36 to 50 years old; 51 to 64 years old). In each age group, 10 plots were chosen and monthly surveys of the population level of C. lameensis were carried out on each plot. At the same time, the number of bunches of oil palm harvested each month on each plot was carefully recorded from the harvest records. The study showed that an increase in the population level of C. lameensis leads to a decrease in production and inversely. Indeed, strong significant negative correlations were observed between the population level of C. lameensis and production. Also, the drops in production were smaller on the oldest plots (51 to 64 years old). In addition, the population level of C. lameensis and production decrease with increasing age of plots. Thus, the highest population level of C. lameensis and the highest production were recorded on the youngest plots (8 to 20 years). Monitoring of palm groves should be regular, especially at a young age in order to avoid, on the one hand, production losses and, on the other hand, to better forecast the periods of decline and increase in production relative to the age of palms