Australia - Probe into insecticide resistance needs grassroots input

Researchers are seeking input from farmers and advisers to assist with their ongoing investigations into insecticide resistance in broad-acre agricultural pests.

Entomologists engaged in research projects funded by the Grains Research and Development Corporation (GRDC) are searching for locations where growers have experienced chemical control difficulties or failures when dealing with insect pests, particularly mites and aphids.

The research being led by cesar* and the University of Melbourne, in collaboration with entomologists across Australia, aims to identify areas at risk and provide early detection of resistant populations.

According to cesar’s Dr Paul Umina, insecticide resistance is an increasing issue for the grains sector.

"Entomologists suspect that the problem is more extensive than has been scientifically confirmed. We are therefore keen to map the geographical spread of the problem throughout Australia’s cropping and pasture regions,” Dr Umina says.

"A number of important crop pests have developed resistance due to the over-use and heavy reliance on chemicals. This includes Helicoverpa, diamondback moth, silverleaf whitefly, Western flower thrips, and several species of mites and aphids.

"Early detection of insecticide resistance in the field will allow management strategies to be implemented by growers to not only reduce pest damage, but minimise the risk of further spread,” Dr Umina said.

University of Melbourne researcher Dr Aston Arthur is encouraging grain growers, farmers and agronomists in Victoria, South Australia and southern New South Wales to provide information that could assist industry with developing a greater understanding of insecticide resistance.

"We want to hear from anyone who has experienced problems with insect pests which appear to have some resistance to insecticide,” said Dr Arthur, who is particularly interested in resistance in mites and aphids.

"We also want to hear from landholders who have paddocks that have been subjected to heavy sprays in recent years so we can assess the insect pest populations to determine whether resistance is building or not, and if growers or advisers know of a paddock with control failures in the past, they are also encouraged to make contact.”

Dr Arthur said resistance in the redlegged earth mite (RLEM) is concerning. Resistance in RLEM was first discovered in Australia only a few years ago on a property in Western Australia, and since then this resistance has spread across numerous properties, spanning a distance of hundreds of kilometres.

"This resistance in RLEM has been found to have a genetic basis where the resistance is passed on to future generations of mites, meaning it can potentially persist in the field indefinitely.”

In 2010 pirimicarb resistance was also detected for the first time in Australia in populations of green peach aphid. There is already resistance to synthetic pyrethroids and organophosphates in green peach aphids in Australia.

"This is of particular concern to oilseed and pulse growers as this chemical has until now been seen as a fall back for aphid populations resistant to other chemical groups,” Dr Arthur said.

Any information obtained by the researchers from growers and advisers will be kept confidential, and assistance can be provided with recommendations for control if resistance is detected in any pest populations tested.

* cesar is a science-based company that delivers environmentally sustainable management solutions in agricultural pest control and wildlife conservation.