Volume
5 Issue 1
May 13, 2008
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.
The
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
|