Northwest Research and Outreach Center

Northwest Research and Outreach Center
2900 University Ave.
Crookston, MN 56716
Phone: 218-281-8604
Fax: 218-281-8603
quirk010@umn.edu

Glyphosate and Preemergence Herbicides

Glyphosate prices have more than doubled since last fall and it seems possible that prices will continue their upward trend. Fortunately most ag co-ops in the RRV have already purchased their anticipated glyphosate needs for the summer. A brief survey of co-op agronomists and others indicate they think supplies may be difficult to find for any ag business that runs short this summer and tries to find additional product. If you haven’t already done so, it might not be a bad idea for you to lock in your needs for the year as prices are not expected to decline.

NWROC-Herbicide-TablesThe typical weed management strategy for soybean producers in the RRV has been two passes of glyphosate. This practice has been cheap, effective, and simple. Though not as cheap as last year, glyphosate is far from being expensive when compared to other input costs. The price increase however, may make a few preemergence herbicides more competitive and worth a second look. Tables 1 and 2 compare the average prices (survey of 3 ag dealers) for glyphosate and four preemergence herbicides that can be used in high soil pH areas. Obviously these prices will vary based on rates and additives, but a single application of glyphosate is still a little cheaper than the average use rates for preemergence herbicides. However, these herbicides bring a couple of other things to the table that you may also want to consider.

Preemergence herbicide Advantages:

  • May help with weeds such as wild buckwheat, smartweed, or common lambsquarters that can more difficult to control with glyphosate
  • Provide another mode of action against weeds as part of a resistance management program
  • Fewer issues with drift injury on nearby crops

 

Preemergence herbicide do have a couple of drawbacks as well that include:

  • Most require rain for activation and lack of rainfall limits weed control
  • Carry over of some products on broadleaf crops
  • Potential for crop injury under cold wet conditions


Carlyle Holen
Extension IPM Specialist—NW MN

In This Issue

May 13, 2008

 

2008 Issues