Development and validation of an integrated pest management strategy for the control of major insect pests on yard-long bean in Cambodia

Abstract Yard-long bean is one of the most popular vegetables, and is extensively grown in Southeast Asian countries including Cambodia. However, yard-long bean production is severely affected by a plethora of insect pests and diseases, and application of chemical pesticides is the main mode of pest control. In order to reduce the over-reliance on chemical insecticides, we evaluated the effectiveness of microbial pesticides (Bacillus thuringiensis and Metarhizium anisopliae formulations), and neem leaf extract alone and in combination (as an IPM package) against aphids, thrips and pod borer on yard-long bean in three different provinces of Cambodia from 2015 to early 2018. The bio-pesticides reduced the incidences of thrips (Megalurothrips usitatus), and the infestation by the aphid (Aphis craccivora) and the pod-borer (Maruca vitrata) to the levels equivalent to chemical pesticide (abamectin) during trials in 2015 and 2016. Although the yield was significantly higher in bio-pesticide treated plots than untreated plots in 2015, the yield did not differ significantly among the treatments in 2016 trials. Multi-location trials during 2016–2018 confirmed that the performance of the IPM package was on par with Farmers’ practice (calendar-based application of chemical pesticides) in reducing the infestations by target pests, without compromising yield. Hence, the IPM package can be a better alternative to chemical pesticides in managing the key insect pests on yard-long bean in Cambodia.