Study of oil palm root pests at Naga Mas Estate, PT Smart, (Indonesia) 18th to 25th June 2000

The purpose of this first mission was to determine the species of Sufetula root-mining caterpillars on oil palm at the Naga Mas estate belonging to PT SMART. However, two other species were found belonging to the family Elateridae. The aim is now to define how much damage is caused by each of the pests. A team of operators was set up in a few days to carry out observations on primary roots using two sampling methods. -One consisted in digging larger 50 x 100 x 40 cm holes. The primary root segments then had a maximum length of 100 cm and the distances were measured between two old attacks, along with the length of new healthy roots. In that way, it was possible to assess the frequency of attacks by the pest involved, and the effectiveness of the treatments carried out. An attempt will be made with these new data to determine the parameter that can be correlated with the number of bunches on each oil palm. It will be either the number of attacks on a given number of primary root segments, or the distances between two attacks, the number of segments without attacks, or the number of segments with one (or more) branching(s) of reiterated roots. -The second method consisted in carefully uncovering one to three oil palm primary roots over their entire length, and measuring the distances between attacks over the entire root length. This provides a picture of the intensity of attacks by larvae depending on the appearance of reiterations on the root. The most severely attacked palms reveal the following outer symptoms: small number of bunches (fewer than 5) and lower leaves (L33 to L25) that are either completely dried out or with dry leaflet tips. Insecticide trials have been proposed to PT SMART. It is also recommended that breeding of the different pests be developed to study their biological cycle, and their respective potential harmfulness. (Résumé d'auteur