Preharvest Intervals for Soybean Herbicides Applied Postemergence

Nearly all herbicide labels (soil-applied or postemergence) have rotational crop intervals that specify the amount of time that must elapse between herbicide application and planting a rotational crop. This becomes particularly important with late-season herbicide applications, and when soil moisture is limited. Additionally, the labels of almost all postemergence soybean herbicides indicate a preharvest interval or a soybean developmental stage beyond which applications cannot be made. Labels of some products may indicate both a developmental stage (before soybean bloom, for example) and a preharvest interval. Preharvest intervals indicate the amount of time that must elapse between the herbicide application and crop harvest. Failure to observe the preharvest interval may result in herbicide residue levels in the harvested portion of the crop in excess of established limits. Also, livestock grazing or foraging treated soybean is not allowed on the labels of many postemergence soybean herbicides. Table 1 contains information regarding preharvest intervals and grazing restrictions for a number of postemergence soybean herbicides.

Table 1.  Preharvest intervals and grazing restrictions for herbicides applied postemergence in soybean.

¹Data, taken from the Roundup PowerMax 3 label, are for broadcast applications in glyphosate-resistant soybean varieties.  Intervals change for applications (spot treatment and preharvest) made to nonglyphosate-resistant soybean varieties.  Forage and grazing allowances can vary among glyphosate-containing products.  Consult the respective glyphosate product label for specific information on forage and grazing restrictions.