10 September 1999

Resistance letters

A WHITE K1 in a black box on the label of Plinth (pendimethalin) herbicide this autumn represents an agrochemical companys first stab at implementing an anti-resistance idea first mooted in 1996.

The aim is for all herbicides to carry letters denoting their modes of action, says pbi Agrochemicals Phil Goodliffe. "It should help growers avoid the development of resistant weeds by using herbicides with different modes of action through their cropping cycles."