Management of Diamondback Moth in Malaysia: Development, Implementation and Impact

With the discovery of the larval parasitoid, Cotesia plutellae Kurdjumov, and the successful introduction and establishment of two other exotic parasitoid species, viz. Diadegma semiclausum Hellen and Diadromus (Thyraeella) collaris Gravenhorst in the Cameron Highlands, biological control was given greater emphasis in the development of IPM for diamondback moth, Plutella xylostella (L.), in Malaysia. An IPM package, based on a three-tiered economic threshold level which takes into account the percentage parasitization of the diamondback moth, was developed in 1987. Results of four trials in the highlands and four in the lowlands established the superiority of IPM over prophylactic control practiced by cabbage farmers. Marketable yields were 5-6% higher, and up to 6-fold increase in profits were obtained in IPM plots. The number of insecticide applications was also significantly reduced from 7 to 9 times in the prophylactic plots to a maximum of only three in IPM plots. No insecticide residue was detected in the crop harvested from IPM plots. Beginning with this first IPM package, two variant packages that take into consideration crop phenology have been developed and are under evaluation. Activities to implement and promote area-wide adoption of the IPM package have been organized, such as seminars, workshops, courses, dialogues, joint trials and field days. A national level committee for vegetable IPM has also been set up to oversee the systematic development and implementation of vegetable IPM country-wide. Over the last 3 years, IPM has achieved significant impact at all levels. The Malaysian government has adopted IPM as a national policy for vegetable pest management. The Malaysian Agricultural Chemical Association (MACA) is receptive to and supports IPM. In a recent census, 54% of the farmers surveyed in the Cameron Highlands are already practicing IPM of diamondback moth and 85% are keen to learn more about the IPM approach.