Rapid resistant weed test offered

The QuickTest service is offered by Plant Science Consulting, a commercial plant and seed testing service run by GRDC-funded weed researcher Peter Boutsalis, Adelaide.

Growers dig up the suspect weeds, shake or even wash off excess soil, ensure the leaves are dry, and post them express mail in zip-lock bags for testing.

When PSC gets the package, the weeds are trimmed and potted until new growth occurs.
“Within a week we get new leaves emerging: it is a young plant again,” says Boutsalis. “Once that happens we spray them in an accurate spray cabinet according to the herbicides the grower wishes to test.”

All grasses can be tested effectively, as can young broadleaf weeds including wild radish and mustards.
“For grass weeds, the QuickTest takes four weeks from the time the plants are received until the results are conveyed to the farmer.” Broadleaved weeds take a little longer.

The advantage of QuickTest, as opposed to testing plants grown from seeds collected from suspect weeds, is that results are obtained months before they would otherwise be. Also, growers know the tests are on the actual weeds that were a problem in the paddock and they don’t have to take the risk of allowing potential problem weeds to set seed.

Boutsalis says there are still times when it’s more convenient to seed test, especially if a trifluralin test is required, given the pre-emergent use of the active.

Regardless of the test used, knowing the resistance status of weeds on your paddocks and farm is advised rather than relying on resistance test results from nearby. “Every paddock is different and testing each paddock for herbicide resistance gives growers a baseline to know whether a particularly herbicide will work – before the investment is made,” Boutsalis says.