Compatibility of trap cropping system and insecticides in managing leafminers Liriomyza spp. (Diptera: Agromyzidae) on shallot crop

Trap cropping system has been widely used as a management strategy against various types of pests. However, the efficacy of this strategy varies and need to be increased by combining it with another additional control strategy. This study aimed to evaluate the efficacy of trap cropping system and insecticides against leafminers, an important pest of crops in the world including in shallot crop in Indonesia. The study was arranged in a randomized complete block design with 6 treatments, which were 1) without any treatments (control), 2) trap crops, 3) botanical insecticide (Agonal), 4) synthetic insecticide (Abamectin) 5) trap crops and Agonal, 6) trap crops and abamectin. The results showed that the trap cropping system has a stronger effect on reducing infestation than the population of leafminers. Trap crops reduced leafminer infestation by around 50% when combined with insecticides but only reduced by 32 % without insecticides. Agonal and abamectin insecticides had similar efficacy against leafminers. Trap crop application combined with insecticides had the highest parasitoid population compared with insecticides and control. This study revealed that trap crops were compatible with insecticides in controlling shallot leafminers and supports the integrated pest management of leafminers.