6533b7d9fe1ef96bd126d3bf

RESEARCH PRODUCT

Le désherbage d’automne contre l’ergot du seigle les traitements herbicides d’automne, un levier chimique efficace de lutte contre l’ergot du seigle

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description

Context and study: Trials in field allowed to show a link between a good grass weeding (blackgrass and rye grass) and extent of ergot contaminations. Makhteshim Agan France and Arvalis tested on 15 trials in 2011-2012, 2 ureas, as isoproturon against blackgrass, alone or in pro-gram with a sulfonylurea, to evaluate their indirect effect against ergot. Field trials were set up on sensitive crops to ergot (rye, wheat and triticale) infested with artificial ergot contaminations and weed seeds sensible to ALS. Contaminations were evaluated first in field on weeds and on crop, and then on harvest, by assessing sclerotia and alkaloids content in harvested samples. results: For all evaluation means of ergot contaminations in field (weed or crop) and in the harvest (sclerotia and alkaloids), treatments against blackgrass decreased ergot contamination, proportionally to their herbicide efficacy (especially programs with fall urea-based application and sulfonylurea-based application in late winter). Treatment effects were observed in “ryegrass trial”, but less visible and especially in the harvest. The protocol used to evaluate the herbicide effect in field against ergot was validated. This study highlighted limits to visually detect sclerotia contaminations in field and in harvest and to deduct alkaloid contamination from sclerotia contamination.