The role of silica in protecting Italian ryegrass (Lolium multiflorum) from attack by dipterous stem-boring larvae (Oscinellafiit and other related species)

The importance of the silica content of the plant as a protection against dipterous stem-borers was studied. Levels of silica in the stubble were inversely related to the degree of infestation by stem-borers in 13 varieties of established swards of Italian ryegrass and also in newly-sown swards of four varieties. There were significant reductions in larval colonisation of Italian ryegrass (cv. RvP) grown on soil watered with sodium silicate solution. A small range of silica content in the stubble was related to large differences in the level of attack by stem-borers.