Avoiding Resistance

“Resistance is a huge issue. We’ve been using chemicals that didn’t work because there was nothing else on the market. The release of Conserve™  Plus is critical to our industry to fight resistance and control insect pests.” Peter Smith, Manildra Grain, Moree.

Australia’s grain industry relies heavily on insecticides to both fumigate and protect grain so that it meets market requirements for insect-free grain. Resistance of grain insects to phosphine fumigation and protectant insecticides is becoming a major problem in Australia. It is expected that the number of resistant insects found will increase over the next five years and is likely to extend across all key grain growing regions.

Prolonging the effective life and availability of fumigants and insecticides, through careful management of resistance, is in the interests of everyone involved in the grains industry.

The GRDC Stored Grain Information Hub is a good place to get up to date information on monitoring grain to identifying key pests.

Key Pests of Stored Grain

Spinosad is now established as the most important active ingredient for controlling LGB resistant to methoprene and/or deltamethrin. The combination of spinosad (nerve acting toxin) and s-methoprene (juvenile hormone analogue) targets the key pest LGB, whilst also providing broad spectrum activity on other key insects.

Conserve Plus delivers robust grain protection, via a significant dose increase over Conserve On-Farm, which is an important step to mitigate the development of resistance.

The table below presents data from a recent study at University of Queensland. Good control of adults and progenyof these key grain pests can be seen for at least nine months.

Key Pests Key Pests
Key Pests Key Pests

Managing Resistance

Australia’s grain industry relies heavily on insecticides and fumigants to protect stored grain from insect pests. As a result, resistance of grain insects to phosphine

and protectant insecticides, has become a major problem. It is expected that the number of resistant insect populations found will increase over the next five years and is likely to extend across all key grain growing regions.

A key issue is that none of the protectant insecticide active ingredients currently available control all of the five key insect pests. As such, combinations of actives are necessary to control diverse populations, of susceptible and tolerant insects, which occur naturally.

The diagram below is a summary of resistance testing up to 2010, indicating the historical use of s-methoprene in combinations with OP’s, targeting LGB. This extension of resistance to OP’s shows that it is critical for growers to rotate to protectants using spinosad or deltamethrin, to mitigate the development of resistance in LGB.

For more information, download the Technical Manual.

Resistance Map Resistance Map
Resistance Map Resistance Map