Aerial spraying with a Bacillus thuringiensis (Bt) product in Estate A resulted in 50% reduction of the Pteroma pendula population by 30 days after treatment (DAT). In Estate B, the bagworm population was completely under control whilst at Estate C, bagworm larval instars decreased by 90% from 0 to 30 DAT. The Bt aerial spray successfully reduced the bagworm population below the threshold of five bagworms per frond in Estates A and B. In Estate C which had a heavy and extensive outbreak, application of the Bt product successfully reduced the bagworm population but the period of application would have to be extended to bring the population below the threshold level. Implementation of the integrated pest management (IPM) system contributed to the successful control of bagworm outbreaks. The aerial spray using Bt had a synergistic effect with beneficial insects in the presence of beneficial plants, and provides longterm control of the bagworm.

Selepas semburan udara, populasi ulat bungkus di Ladang A menurun sebanyak 50% daripada lima larva/pelepah 0 hari selepas rawatan (HSR) ke 2.5 larva/pelepah (30 HSR). Di Ladang B pula, populasi ulat bungkus telah dikawal sepenuhnya manakala di Ladang C, populasi ulat bungkus menurun sebanyak 90% dari 412 larva/pelepah (0 HSR) ke 40 larva/pelepah (30 HSR). Semburan udara Bt telah berjaya mengurangkan populasi ulat bungkus di bawah nilai ambang di Ladang A dan Ladang B, berbeza dengan Ladang C disebabkan serangan ulat bungkus yang amat serius di lading tersebut. Aplikasi susulan semburan udara Bt di Ladang C perlu dijalankan bagi mengurangkan populasi ulat bungkus di bawah nilai ambang iaitu 5 per pelepah. Amalan sistem pengurusan perosak bersepadu yang lestari juga menyumbang kepada kejayaan program semburan udara Bt. Gandingan yang serasi di antara tanaman berfaedah, serangga bermanfaat dan Bt memastikan kawalan jangka panjang dan mengelakkan serangan ulat bungkus berulang.