Other Crop Herbicides May Not Be Compatible with Seedling Alfalfa

  
DO NOT USE Glean^®, Amber^®, and Finesse^® to control weeds on the wheat crop preceding the planting of alfalfa, since residues of these herbicides can seriously damage seedling alfalfa. For all of these herbicides, a "Field Bioassay" must be conducted before planting alfalfa. A 'Field Bioassay' means planting alfalfa and observing it to see that it emerges and grows normally. (See Rotational Restrictions under "Other Notes" and discussion in Alfalfa Stand Establishment Questions and Answers. OSU Extension Circular E-949 , Pg. 7).   

Rotational Restrictions: Herbicide carry-over from previous crop can injure seedling alfalfa. Often the "variety", "weeds", or "weather" are blamed for poor alfalfa stand establishment when in fact it can be herbicide "misuses", including forgetting when, what, or how much herbicide was applied on previous crops. A listing of alfalfa planting restrictions following herbicide use in previous crop is listed in the following table.
 

The use of the sulfonylurea herbicides (such as Glean^® and Amber^®) on the wheat crop before planting alfalfa has resulted in severely stunted alfalfa seedlings in a number of fields in Oklahoma. This has been particularly evident after dry summers following herbicide application. To be safe, always read and follow crop restrictions on herbicide labels. This includes keeping accurate records as to: What chemical was applied?; When was it applied?; How much was applied?