A range of naturalised harmful plant storage pests including beetles, psocids, moths and mites habitually threaten the food safety, market access, trade and the overall profitability and sustainability of the Australian grain industry. Some of these pests have already been detected with resistance to phosphine and the spread of resistance is on the rise annually. In addition, new resistances are also being developed, a recent example being the detection of strong resistance to phosphine in several populations of flat grain beetles.

What is the biosecurity problem?

Australian export regulations require that all grain exported from Australia is free from insect infestation. This ‘nil tolerance’ standard is also adopted by domestic markets.

The Australian grain industry relies on chemicals, particularly phosphine fumigant, as the key tools used to meet the ‘nil tolerance’ standard. A major drawback, however, with this strategy is the threat of resistance in target species.

A major difficulty for the industry is that there is no practical replacement for phosphine and there are very few contact insecticides suitable for application to stored grain. Faced with this scenario, the industry has no choice but to maintain the tools that it has and must adopt a resistance management strategy to achieve this.

The main outputs of this project are to:

• improve understanding of the factors involved in the development of resistance to phosphine
• validate phosphine resistance management tactics
• improve understanding of distribution of species of flat grain beetle species and the role of gene flow in selection for resistance to phosphine 
• validate molecular resistance diagnostic tools and analysis of resistance gene frequencies.  

Who will be the end-users of this research?

The primary end-users will be:

• grain companies, farmers and other grain storers. In particular, individuals with responsibility for managing grain biosecurity
• officers with responsibility for biosecurity research and policy within government and non-government organisations.