Integrated Crop Management News

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Weeds likely are emerging with corn in many fields due to the lack of a preemergence herbicide. Whether this was planned or due to weather constraints, it is critical to control weeds early in order to protect yields. The term critical period is used to define how long weeds can be allowed to compete with the crop before yields are impacted. To obtain maximum yields, weeds must be controlled before the critical period is reached. The difficulty in relying on total post programs is the variability in the critical period, making it impossible to predict the optimum time for postemergence herbicide application.

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Iowa State University



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