Towards developing a sustainable management strategy for legume pod borer, Maruca vitrata on yard-long bean in Southeast Asia

Legume pod borer, Maruca vitrata, is a serious production constraint on yard-long bean which is grown over 7% of the total vegetable production area in Southeast Asia. It can cause up to 80% yield loss on various host plants, and because it is hidden within the pods, it is difficult to control with chemical pesticides. However, farmers rely heavily on the use of chemical pesticides to control M. vitrata. Intensive and indiscriminate use of pesticides leads to the development of resistance in M. vitrata to chemical pesticides, degrades the environment, kills natural enemies, and causes resurgence of secondary insect pests. To reduce pesticide residues in vegetable legumes and to promote better human health, an integrated pest management strategy based on sex pheromones, natural enemies, and bio-pesticides is being developed based on applied research. Since phenotypic variations have been observed among populations of M. vitrata in Southeast Asia and sub-Saharan Africa, M. vitrata populations present in Southeast Asia with reference populations from sub-Saharan Africa have been characterized. The inconsistency in the performance of sex pheromone lures has become an obstacle in implementing trap-based pest monitoring of M. vitrata. Appropriate pheromone blends for each geographical region are being developed based on the variations in pheromone production and reception in M. vitrata. With a more systematic effort, novel species-specific parasitoids of M. vitrata have been identified in Lao PDR, Taiwan, Thailand and Vietnam. Studies have indicated the potential susceptibility of M. vitrata to Bacillus thuringiensis, Beauveria bassiana, Metarhizium anisopliae, Maruca vitrata multiple nucleopolyhedrovirus, and neem.