GLASSHOUSE EVALUATION ON THE EFFICACY OF BACILLUS THURINGIENSIS (BT) AGAINST BAGWORM, METISA PLANA AND NON-TARGET EFFECT ON OIL PLAM POLLINATOR, ELAEIDOBIUS KAMERUNICUS (FAUST)

Abstract

Evaluations on the performance of selected bioinsecticides and recommended chemical insecticides to suppress the bagworm, Metisa plana (Walker) infesting oil palm, were carried out in a glasshouse environment. The results showed that a series of biological products using Bacillus thuringiensis (Bt) is effective in killing 80 per cent of bagworm larvae within 7 to 15 days after application (DAA). Among the biological products, the Bt1 product showed the highest efficacy, killing 99.72 per cent of the bagworm population at 7 DAA. Although slow in reacting, Bt products were highly toxic to the adults, and less effective on the emergence of pollinator weevil,Elaeidobius kamerunicus (Faust). The chemical insecticide, cypermethrin was the most effective compared to all other treatments (p<0.05), killing 100 per cent of the bagworm larvae in only 3 DAA. All non-Bt based insecticides, including cypermethrin, were toxic to both adults and emergence of the weevils. There was no significant difference in the number of adult emergence between the non-treated (control) and Bt-insecticides, but significantly was lower when treated with other insecticides (F= 93.75 p<0.05). Based on its high performance, the biopesticide Bt1 product has a higher potential to be tested in the field for integrated leaf-eating caterpillar management programme. To ensure consistency in their efficacy, these bio-insecticides need further evaluation in large-scale trials, especially in oil palm fields infested with bagworms in epidemic proportions. Keywords: Bagworms, Bacillus thuringiensis, non-target effect, pollinator, oil palm