by Lisa Herbert, Ph.D. ABC Rural, Brisbane, Australia
Organic chemist Dr. Stephanie Smith has developed the chemical lure to attract this beetle into a trap before it makes its way into grain storage facilities. Like most beetle pheromones, the synthetic rusty grain beetle pheromone was difficult to make. This is a significant discovery because the rusty grain beetle has one of the highest levels of resistance to phosphine throughout the world. Pests in grain have traditionally been controlled using fumigant insecticides, but the rusty grain beetle is becoming resistant. This pheromone baited trap can help capture the beetle and offer it a simple field test to determine its level of phosphine resistance. Fumigators can then adjust the dosage rate of phosphine. Phosphine will still kill all stages of insect life if the correct dosage is applied.
There are two compounds that the insects use to signal each other that they want to aggregate. They will inevitably mate once they’re together. This pheromone will attract both male and females. Dr. Smith said “The lures, which last a month, are currently being trialled around the country as a ‘detection tool’. We have not registered this as a control agent, at this stage.” The pheromone, created in a laboratory in suburban Brisbane, are put into the small rubber lures inside insect traps placed near grain silos. Dr. Smith said: “Luring the rusty grain beetle into traps, instead of fumigating grain with high doses of phosphine, could have significant implications for international trade. So phosphine is showing high levels of resistance and it has properties that worry the ultimate clients of the grain so we have to assume that it’s a good idea to have an alternative and this pheromone could be a potential alternative.”
Insects Limited is currently testing this beetle pheromone. There will be more discussion about this new discovery at the 12th Fumigants & Pheromones Conference in Adelaide, South Australia.