EFFECT OF BAGWORM Pteroma pendula Joannis ATTACK ON THE DECREASE IN OIL PALM PRODUCTIVITY

Abstract

Outbreak of oil palm bagworm Pteroma pendula has been reported within the last few years in several plantations in North Sumatra. A study was conducted to determine the impact of P. pendula attacks on oil palm productivity. Aerial photograph was taken in November 2016 and analyzed to determine the level of damage on each palm canopy. The damage symptoms were classified onto healthy palms as control plants (score 0), mild (score 1), moderate (score 2), severe (score 3), and very severe (score 4). The sample palms were randomly selected and observed for the sex ratio, bunch number and bunch weight at 18 months after defoliation. The attack of P. pendula at the highest level (score 4) caused a significant effect on sex ratio and the number of bunches produced. The fresh fruit bunches production was declined 21.02–36.35% on palms with moderate to very severe attack (score 2–4). Similar palms also have a potential case of inflorescences abortion 18.41–32.54%. However, the average bunch weight was not influenced by P. pendula attack.

Keywords

• bunch number
• bunch weight
• pteroma pendula
• sex ratio