28 August 1998

True ICM key factor in effective control

TECHNICAL services manager with Brown Butlin, Jim Butchart, broadly agrees with Mr Mills advice but stresses that containing blackgrass involves true integrated crop management.

"You cannot just magic control out of a bottle." Growers must concentrate on producing good seed-beds to optimise herbicide performance and take every opportunity to break the weeds life cycle through spring cropping. "This is real ICM."

Mr Butchart reinforces the spray timing message. "It is increasingly vital." But not all growers have access to machinery to apply Avadex, he says. "We are finding Prebane (terbutryn) pre-em gives blackgrass control within a percentage point or two of Avadex and is a viable alternative."

Growers dissatisfied with control and unsure of the resistance status of a field must take steps to determine it, through specific tests or even through their own trials, he suggests. "It could help a lot. Patterns of cross-resistance are increasingly complex so you almost need to test the different chemistry in every field."

Where resistance is suspected but not yet proven, he still favours Hawk to follow Avadex or Prebane. "Besides clodinafop it contains trifluralin. Two chemicals with different modes of action as a follow up to Avadex is the strongest possible anti-resistance strategy. But you must be spot on with timing because the sensitising effect of Avadex or Prebane only lasts about eight weeks. Hawk must be on by the time most blackgrass is at the two-leaf stage.

"If you have target site resistance then the choice is Avadex/Lexus – no question!" &#42

BLACKGRASS CONTROL

&#8226 No herbicide blueprints.

&#8226 Resistance status important.

&#8226 Trifluralin useful early role.

&#8226 Prebane as Avadex alternative?

&#8226 Seed-beds & spray timing vital.