The first phosphine resistant species detected in grain stores in NSW was found in 2007, and the last decade in farming across Australia has seen a dramatic rise in phosphine resistance pest species.
With markets expecting high-quality grain that shows no signs of pest infestation, growers have turned to a heavy, often misuse of phosphine, to ensure the highest quality, pest-free grain.
This reliance, however, seems to be what is leading to phosphine resistance in pest species; predominantly lesser grain borer, rusty grain beetle, rust red flour beetle, rice weevil and saw-toothed grain beetle.
There are several reasons for the rise in phosphine resistance in grain stores, detailed below: