
Fumigant resistance: small victories in an unrelenting battle
As insect resistance to phosphine continues to climb across both on-farm and bulk storage, growers face a constant challenge: how to slow resistance while protecting grain quality and market access. Recent GRDC-supported resistance monitoring shows a slight dip in strong phosphine resistance this year, but the overall national trend remains upward, with about 30 per cent of pests now showing strong resistance—well above the 10–15 per cent level considered manageable.