26 December 1997

New herbicide test pinpoints resistant weed in quick time

By Charles Abel

HOW would you like to know whether your hard-to-kill blackgrass is herbicide resistant now, rather than next autumn?

That is the claim herbicide supplier Novartis is making for its new QuickTest, a service designed to help growers adapt spring herbicide programmes and cultural controls in the current season.

Indeed, a window-sill kit could be made available, allowing growers to check the herbicide resistance of their grass-weed populations themselves.

"Current tests grow plants from seed, so can only be done after the grass has seeded in the summer," says product manager, Andy Piggott. "Results then take up to four months to produce, so are too late to influence weed control in the current crop or cultural control in the following crop."

QuickTest has been developed in Switzerland to help agronomists combat herbicide resistant grass weeds throughout the world. It suits most grass weeds, including blackgrass and wild oats, and can be used any time between the two to three leaf growth stage and ear emergence. Results come back within four weeks of sampling.

The test was developed by Peter Boutsalis at Novartiss research headquarters in Basel. It is believed to involve growing the meristems from sampled plants on a herbicide-impregnated medium.

"The test can be used to check for resistance to all herbicides, not just those subject to target site resistance, as with the French stem and leaf tests," explains Mr Piggott. It also gets round the summer-only timing of the fast French pollen test (Arable, 28 Nov).

"We can check the complete resistance profile of a grass weed sample with this test, helping advisers develop the most appropriate advice for each case."

Reliability is said to be 100%, if a suitable sample has been collected. Sample sizes will range from 30-60 plants.

But QuickTest will not be available until 1999, says Mr Piggott. In 1998 only Novartis distributors in high risk areas will use the test to check the logistics of collecting and posting samples from 25 key sites to Novartis in Cambridge. Samples will be taken monthly from January onwards.

Cost is significantly less than the £100 a sample charged by commercial testers now, notes Mr Piggott. Whether QuickTest will be a paid-for service, a licensed test or freely available is unclear.

Novartis hopes the test will find favour in the industry, leading to standardised herbicide resistance testing.

QUICKTEST

&#8226 Herbicide resistance test for all grass weeds and all herbicides.

&#8226 Can be used from 2-3 leaf to flowering growth stages.

&#8226 Results in 4 weeks.

&#8226 Use to modify weed management in season and for next year.

&#8226 Window-sill test possible.

A new test that can identify all types of herbicide resistance in grass weeds in just four weeks could revolutionise anti-resistance strategies, says Andy Piggott.

QUICKTEST

&#8226 Herbicide resistance test for all grass weeds and all herbicides.

&#8226 Can be used from 2-3 leaf to flowering growth stages.

&#8226 Results in 4 weeks.

&#8226 Use to modify weed management in season and for next year.

&#8226 Window-sill test possible.