STUDIES ON THE BIOLOGY AND INFESTATION OF STEM BORER, BATOCERA RUFOMACULATA, IN DURIAN

The study on the longhorn stem boring beetle in durian was carried out in major durian producing areas of Thailand during October 2002 to July 2005. A series of studies including the survey on infestation, infestation behavior, courtship and oviposition behavior, and life cycle were conducted. The results show that the infestation occurs in all durian planting areas throughout Thailand where durians in the north-eastern and eastern planting areas were the most serious. Heavy infestation of this pest causes durian trees to die and farmers could not solve the problem. There were more than one species of longhorn beetles infesting durian but Batocera rufomaculata De Geer was the most prevailing. Female beetle chews a small tunnel shaped depression in the tree bark and inserts an egg under the bark. After hatching from the egg, the neonate larva initially feed under the bark. Young larvae begin feeding in the phloem tissue then migrate into the heartwood to pupate. Damage from small larvae was difficult to be observed, but hole, dripping sap, and frass can be observed on the bark when they grew up. Full grown larva is 8-10 cm in length. Larval and prepupal + pupal stage lasts about 280 and 24-29 days, respectively.