28 November 1997

Resistant blackgrass found fast

FRENCH researchers reckon they can detect herbicide resistant blackgrass in as little as two hours.

Conventional tests mimic field spraying and take four to five weeks to produce, often inaccurate, results, says Anne Letouzé of INRA.

The new two-hour test uses pollen germination, but is only suitable for detecting target site resistance, she acknowledges.

Growing seedling shoots exposed to acidified herbicide solution detects both enhanced metabolism and target site resistance and gives a result within six days.

A possible farm test checks the death of plant tillers kept in herbicide solution. It uses plants at the end of winter and gives a good indication of resistance after two days. However, it may not detect enhanced metabolism resistance, says Ms Letouzé.

IACR Rothamsted researcher Stephen Moss is developing similar tests and hopes to have some on show at Cereals 98.

French blackgrass test promises fast results on herbicide tolerance, says Anne Letouzé