Pre-em herbicide swtich may yet be merited

21 September 2001

Pre-em herbicide swtich may yet be merited

PRE-EM blackgrass control for early-sown cereals may still need changing if warm weather returns.

Growers planning to apply Avadex (tri-allate) should remember higher temperatures shorten its residual life, says Bob Mills of Banks Cargill. "For maximum sensitisation you need four to six weeks before applying a post-emergence treatment."

If mild conditions return, Crystal (flufenacet + pendimethalin) could suit early crops better, says Mr Mills, who believes its residual activity and different mode of action could make it more robust.

"If the target is just blackgrass you would normally struggle to tell the difference between Avadex and Crystal. And where you have blackgrass and wild oats Avadex probably has the edge.

"But the other advantage of Crystal is that it definitely has the edge where ryegrass and meadow grass are an issue."

Full rate Crystal at 4 litres/ha for serious blackgrass costs about £32/ha (£13/acre), he adds.

"Thats clearly more than the £22 for 15kg/ha of Avadex. But many growers might have to pay a contractor £7.50-£8/ha to get it on." Crystal can be applied by farm sprayers. &#42

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