Influence of silicic acid foliar spray on the incidence of sucking insect pests and their natural enemies in rapeseed

Silicon induces resistance in various crops against insect pests of diverse feeding guilds, including hemipterans, through upregulation of plant defense mechanisms along with maintenance of plant physiological processes. The present investigation to study the effect of silicon in the form of silicic acid (SA) against major sucking insect pests (Lipaphis erysimi and Bagrada hilaris) and natural enemies (Coccinella transversalis and Episyrphus balteatus) in rapeseed revealed that the foliar application of SA @ 0.4% thrice at 30, 40 and 50 days after sowing significantly reduced the colonization of L. erysimi as against non-significant effect on the population of B. hilaris. Three sprays of SA @ 0.4% significantly increased the population of C. transversalis without any significant effect on E. balteatus population. The silicon content of the rapeseed grains was also found to be significantly enhanced (0.32%) with 3 sprays of SA @ 0.4%.