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.