Corn-soybean is the most common cropping system in eastern Nebraska. While corn growers are getting ready for planting this season, it is important to pay attention to the planting interval of herbicides applied the previous year in soybean.

Certain soybean herbicides have relatively longer planting intervals for corn, especially if they are applied post-emergence in soybean. This is particularly important because soybean planting was late last year in much of Nebraska due to May rains. This caused post-emergence herbicides to be applied later in the season than they might normally be, making it important that you pay attention to the planting interval.

For example, herbicides with fomesafen (Flexstar/Rumble/Marvel/Flexstar GT) have 10 months of planting interval for corn.  When herbicide tank-mixture is applied, consider the longest planting interval mentioned for any tank-mix partner.

Popcorn and sweet corn are more sensitive to herbicides as compared to field corn; therefore, certain herbicides have a longer planting interval for popcorn/sweet corn. For example, Pursuit has a planting interval of 8.5 months for field and seed corn, but 18 months for popcorn and sweet corn.

Resource For more information on herbicides and planting intervals, check the latest Guide for Weed, Disease, and Insect Management in Nebraska, available to order from the Nebraska Extension Publications website.