EFFECTIVENESS OF Bacillus thuringiensis AERIAL SPRAYING AGAINST THE BAGWORM, Metisa plana WALKER (Lepidoptera: Psychidae) OUTBREAK IN OIL PALM USING DRONE

Abstract

Bagworms have been a severe threat to the oil palm industry and have endangered mostly smallholdings. Thus, aerial spraying of Bacillus thuringiensis (Bt) based bioinsecticides using an agricultural drone was carried out to control the bagworm infestation at a severely infested oil palm smallholding located in Sepang, Selangor, Malaysia. The drone was equipped with VP110 nozzle at the pressure of 0.2 MPa with a permanent speed of 2.8 m s–1. The flying height was set 2 m above the canopy. The first round of drone spraying conducted on 4 July 2017 has successfully reduced the larval population of the bagworm, Metisa plana from 304.5 larvae per frond (LPF) at 0 days after treatment (DAT) to 12.1 LPF at 28 DAT, resulting to 96% reduction in the larval numbers. However, some of the larvae survived to the pupal stage, with approximately 64.52 pupae per frond (PPF) recorded at 28 DAT. The second drone spraying conducted on 27 August 2017 has effectively decreased the larval number from 109.25 LPF at 0 DAT to 9.3 LPF at 28 DAT, resulting in 91.5% of larvae reduction with zero pupae recorded. The results showed a great potential of drone aerial spraying in controlling bagworms at oil palm planting areas.