Considering diverting portions of your grain crops into feed crops? Dont forget to check the preharvest intervals for applied crop protection products




June 28, 2023

With the dry conditions we are experiencing this year in much of Wisconsin (and beyond), securing enough feed becomes a concern and top priority for dairy farmers and livestock producers. As farmers consider diverting portions of their grain crops into feed crops, it’s important that they consider and respect the preharvest intervals for all crop protection products applied to their crops during the growing season.

The preharvest interval (PHI) is the minimum amount of time between the application of a crop protection product (i.e., herbicide, fungicide, insecticide) and when the treated crop can be legally harvested for forage/grazing or for grain. The U.S. Environmental Protection Agency (US EPA) has set limits on the residue levels (“tolerances”) of registered crop protection products for each labeled crop and the PHIs are in place to help meet these safety standards thus reduce the risk of animal and/or human dietary exposure. The PHI information is available on the product label, typically under “Restrictions”. Note that the PHI may or may not be the same for forage/grazing and for grain harvest. See below for examples of the PHI information found on the label of common corn herbicides:

For additional information, please check: A3646 Pest Management in Wisconsin Field Crops. Always check the product label. The label is the law.

This article was written by Dr. Rodrigo Werle, Associate Professor and Extension Cropping Systems Weed Scientist at the University of Wisconsin-Madison.