Pheromones “Down Under”

by Pat Kelley, BCE, Vice President

Dr. Daglisch’s group studied both the seasonal and spatial patterns of these beetles. They did this by counting beetle numbers captured in traps containing the aggregation pheromones of the different beetles. The traps were placed at grain storage sites and non-storage (natural) sites. The seasonal studies showed that even in this very warm country, neither the lesser grain borers nor the red flour beetles take flight in the cooler winter months. When temperatures rose above 25° C (77° F), the flight activity began and the beetles could potentially fly up to a distance of one kilometer (.62 miles). In Greg Daglisch calls himself an “Applied Entomologist”. Working as the Principle Research Scientist with the Queensland Department of Agriculture, Fisheries and Forestry (DAFF) in Australia, Daglisch has become an expert in postharvest grain biosecurity and has worked extensively with stored product beetles in the “Land Down Under”.

As an invited guest speaker at this year’s 12th Fumigants & Pheromones Conference in Adelaide, Australia, Daglisch told the international crowd that he is always looking for ways to exploit pest insects in the Australian grain industry. He has done this in part through the trapping studies of three prominent pest beetles: the lesser grain borer, Rhyzopertha dominica, red flour beetle, Tribolium castaneum and rusty grain beetle, Cryptolestes ferrugineus.

Pheromones Down Under

Daglisch’s group studied both the seasonal and spatial patterns of these beetles. They did this by counting beetle numbers captured in traps containing the aggregation pheromones of the different beetles. The traps were placed at grain storage sites and non-storage (natural) sites. The seasonal studies showed that even in this very warm country, neither the lesser grain borers nor the red flour beetles take flight in the cooler winter months. When temperatures rose above 25° C (77° F), the flight activity began and the beetles could potentially fly up to a distance of one kilometer (.62 miles). In Australia, the ability of these beetles to fly and disperse during 9+ months of the year, allows the spread of phosphine resistant strains over a considerable portion of the country.

As a means of science helping industry, a big part of Daglisch’s job is spreading the word to farmers that these beetle species (both resistant and non-resistant strains) can fly relatively far distances. They can fly into grain silos from neighboring silos or they can even fly in from nonstorage sites like forests and fields. A key part of preventing grain loss in Australia comes through the education of people involved in the grain industry. Farmers must know that when flight activity begins, there is an immediate increase in infestation pressure. They must also know that flight activity can begin long before the harvest and they should prepare for that. It becomes a matter of not “if” but “when” the beetles will arrive.

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