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RESEARCH PRODUCT

Autumn herbicides, an efficient chemical tool against ergot of grasses

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Maktheshim Agan France analyzed 14 weeding trials, carried out in 2011-2012, to identify the indirect effect of weeding on the development of ergot. Field trials were set up on straw cereals (rye, wheat and triticale), with a contamination of ergot sclerotia and artificial infestation of grassy weeds susceptible to sulfonylureas. Two herbicides: isoproturon and chlortoluron, used alone or followed by a sulfonylurea, were compared to untreated control. All the assessments show that herbicides decreased the amount of sclerotia and even more the alkaloid content in harvest. This effect was higher with the herbicide program (urea applied in autumn /sulfonylurea at the end of winter). This study highlighted the limits to visually detect sclerotia and a bias to deduct alkaloids contamination from sclerotia weight. Cleaning work of harvest cannot fully ensure the absence of contamination. An upstream consideration of ergot, by weeding, is thereby necessary.