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

SUMMARY 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.