A rapid test could combat a major threat to Australian cotton production, by determining if resistance aphids are present in crops.

The test can be used prior to insecticide control, to eliminate failure of expensive spraying, rendered ineffective by resistance.

At the Elizabeth Macarthur Agricultural Institute (EMAI), Camden, Dr Martin McLoon, molecular biologist with NSW Department of Primary Industries and senior research scientist in insecticide resistance, Dr Grant Herron, have developed and trialed a molecular assay over the past two seasons.

They can provide results in 48 hours, compared to between four and eight weeks for current bioassay tests.

"The cotton aphid has become a major pest of Australian cotton by developing resistance to the carbamate insecticide Pirimor and organophosphates generally," Dr McLoon said.

"Until recently these pesticides were very effective, but resistance in the cotton aphid has proven to be a major threat to production.

"We have been carrying out molecular tests to establish resistance, monitoring insecticide and collecting aphid from fields where insecticide failures or problems have been experienced.

"These are tested against a range of current control options allowing the early identification of emerging resistance problems.

"We’re also keeping track of existing aphid problems as part of an overall insecticide resistance management strategy for cotton."

The rapid laboratory based test for pirimicarb resistance will be implemented this year into the resistance monitoring program.

If management of aphids failed, the cotton industry would face the prospect of cotton aphids damaging crops and in terms of quality, causing sticky cotton.

"That would have an immediate and severe downgrading of the crop value but more importantly jeopardise the good name of Australian cotton and its reputation for producing a clean high quality product," Dr Herron said.

Dr Herron had collected reference strains of aphids over many years and the project gained impetus when Dr McLoon was assigned to his group three years ago.

They are now tackling the emerging pest problem of mirid control and its development of insecticide resistance.

Contact Martin McLoon, (02) 4640 6453 or Grant Herron (02) 4640 6471, Camden.