PRE-EMERGENCE herbicides are key to controlling blackgrass in wheat crops, say experts.

Up to 50-80% of the yield increase achieved by controlling blackgrass can be attributed to the pre-emergence component of herbicide programmes, according to trial results.

“This revealing result emphasises the continuing importance of the pre-emergence treatment where high levels of blackgrass are expected,” said Rothamsted Research‘s Stephen Moss.

“In addition, the inclusion of a pre-emergence herbicide is often a useful component of a resistance management strategy because it allows the use of alternative modes of action to many post-emergence products.”

Growers with serious blackgrass problems need to do the best possible job pre-emergence, stressed BASF‘s Andrew Jones.

“Compromises at pre-emergence level may have implications further down the line.”

Increased dormancy this year means the main blackgrass threat will not appear until after crops have been drilled, he said.

“A significant reduction in the grass weed population by using pre-emergence Crystal (pendimethalin + flufenacet) will be a key factor in the efficacy of the whole programme and in resistance management,” he suggested.