This is the final report for CRC50060 “Phosphine fumigation of cool grain”. The project began as GRDC project DAQ00098 and was incorporated into the CRC National Plant Biosecurity on 1 July 2007 as part of the supplementary bid to include stored grain.

Aims and objectives

The biosecurity problem addressed was the need to understand and evaluate phosphine fumigation of cool grain (i.e. 20°C or less) as a means of controlling resistant biotypes of insect pests of stored grain which are major EPPs threatening the grain industry. The benefits of cooling and phosphine fumigation are that cooling preserves grain quality and reduces insect population growth, and phosphine kills insects and has a residue free status in all major markets.

The research objectives were to:

• conduct laboratory experiments on phosphine efficacy against resistant insects in cool grain, and determine times to population extinction.
• conduct laboratory experiments on phosphine sorption in cool grain and quantify.
• complete fumigation trials in three states (Qld, WA and NSW) on cool grain stored insealed farm silos.
• make recommendations for industry on effective phosphine fumigation of cool grain.

Phosphine is used by growers and other stakeholders in the grain industry to meet domesticand international demands for insect-free grain. The project aim was to generate new information on the performance of phosphine fumigation of cool grain relevant to resistant biotypes. Effective control of resistant biotypes using phosphine to fumigate cool grain will benefit growers and other sectors of the grain industry, needing to fumigate grain in the cooler months of the year, or grain that has been cooled using aeration.