Defense response induced by silicon amendment against Scirpophaga incertulas (Walker) and Cnaphalocrocis medinalis (Guenee) infestation in rice

Abstract

Considering silicon (Si) amendment as an eco-holistic approach in insect pest management, an attempt was made to optimize the dose of diatomaceous earth (DAE), an organic silicate fertilizer and study the mechanism of resistance against stem borer and leaf folder infesting rice. Basal application of this product at 50-500 kg ha-1 effectively restricted damage by both the insects in rice cv.TN1 and increased the crop yield by 22-80% over control as against 74% increase in standard check, calcium silicate applied at 2000 kg ha-1. An enhancement of plant resistance to these pests was conspicuously observed at different doses of DAE. The best performance was exhibited at 300 kg ha-1 with a record average of 9.46% dead heart and 3.26% white ears due to stem borer and 1.84% leaf damage by leaf folder compared to corresponding damage of 22.34, 19.40 and 3.33%, respectively in untreated control. This induction of plant resistance was attributed to higher silicon deposit supported by marked impact of feeding stimuli from stem borer in altering the chlorophyll, phenol and protein contents of the rice plant.