Evaluation of insecticides performance for the management of leaf miners in Fenugreek (Trigonella foenum-graecum L.)

Abstract

Fenugreek (Trigonella foenum-graecum L.), an ancient leguminous crop with medicinal properties, is widely consumed as green leaves, pods, and seeds. Leaf miner infestation, causing white tunnels in leaves, significantly reduces leaf vigor and productivity. An experiment using a Randomized Complete Block Design with seven chemical treatments and three replications aimed to combat this pest. Observations were made on three leaves of five plants per plot, assessing percent leaf infestation before treatment and at 1, 3, and 7 days post-treatment over two years (Rabi-2020 and Rabi-2021). Results showed that Chlorantraniliprole at 30 g a.i. ha-1 was most effective, with the lowest leaf miner infestation (19.16%) and highest yield increase (58.38%), achieving an Incremental Cost Benefit Ratio (ICBR) of 1:9.1. Following this, cyantraniliprole at 90 g a.i. ha-1, thiamethoxam at 25 g a.i. ha-1, and chlorantraniliprole + thiamethoxam (soil drench) at 150 g a.i. ha-1 also showed effectiveness. Notably, thiamethoxam at 25 g a.i. ha-1 had the highest ICBR due to its lower cost. Farmers are advised to use newer insecticides like chlorantraniliprole and cyantraniliprole to mitigate yield losses from leaf miner infestations. These insecticides demonstrated significant efficacy in protecting fenugreek crops, particularly where the economic value lies in the leaves.