Silicon amendment induces resistance in rice to Diatraea saccharalis (Lepidoptera: Crambidae)

Abstract

Amendment of soil with Silicon (Si) is known to enhance plant resistance against insect pests and can be used as a tool to improve management of rice stem borers on rice. A study was conducted to investigate the use of Si to induce resistance in rice plants and the effects of Si on the development of Diatraea saccharalis (Lepidoptera: Crambidae). The experiment was carried out in a 3 × 3 factorial scheme (cultivar × Si) arranged in a randomized complete block with four replications, where the rice cultivars Canela de Ferro, BRS Esmeralda and IR 42 were combined with a mixture of calcium and magnesium silicate at three rates (control, 300 and 600 kg ha−1) applied in the soil before seeding. Plants were infested with 10 neonate larvae/pot at pre-flowering stage (60 days after plant emergence). Twenty-five days after infestation, plants were cut at ground level and taken to the laboratory where the stems were examined and the following variables determined: silicon content, number of live larvae, larval weight, relative growth rate of larvae, number of total stems (tillers), number and percentage of damaged stems and larval boring success. Si caused a negative effect on D. saccharalis development on Si treated plants compared to non-treated plants. Si treated plants were less damaged compared to non-treated plants. Amendment of soil with Si proved to be effective to enhancing rice resistance to rice stem borer, probably due to the increase of Si content in plant tissues. The response of susceptible rice cultivar to Si application indicates that adding silicates to soil is a good tool for reducing infestation and damage of stem borers to rice.