By Sachin Dhanda and Sithin Mathew et.al
As postemergence herbicide spraying is ongoing in Minnesota this week, this is a reminder that all the applications should follow the growth stage cutoffs specified on herbicide labels for postemergence applications and to comply with the preharvest interval (PHI) which is legally required.
The PHI represents the minimum time between the last herbicide application and the crop harvest.
The restrictions are in place to prevent potential crop injury, herbicide carryover, environmental or food safety issues, and other concerns. If tank mixing two or more herbicides, the cutoff is determined by the most restrictive labels.
Source : umn.edu