If you are a wheat grower, ryegrass management must be considered as early as planting. Ryegrass continues to increase, and it is safe to assume that the Hoelon-resistant ryegrass problem continues to increase.
If the fields being planted do not have a ryegrass problem, things are simple. However, if the fields do have a problem, then you must decide quickly how you are going to manage it.
If you have been using Hoelon or Achieve and they have been providing good control, they could be used again this year. Ask yourself, however, how intensely wheat is cropped in that field, and how many years Hoelon or Achieve has been used?
Hoelon and Achieve are not the same herbicide, but they have the same mode of action. Rotating or alternating them can not be considered an effective resistance management strategy.
If the field is planted to wheat on a regular basis, and if one of these herbicides has been used several years in a row, an alternative management strategy should be considered.
The options for managing to control resistant ryegrass or managing to prevent it are limited. There are new herbicides coming that will help. As I find out the status of these for this season, I will pass along the information.
One herbicide that has been used with some success the past couple of years is Finesse. We have had, by far, the best results with it when used as a pre-emergence herbicide applied immediately after planting. While it is also labeled as an early postemergence treatment, it has not been effective on emerged ryegrass.
It takes rainfall for activation, and one normally would assume that will happen with good predictability in the fall. However, we have had a dry fall the past couple of years and activation was a problem in some fields.
There has been an occasional injury problem in the field and it has normally been associated with very shallow seeding. For this reason, it is best-suited for use in drill-seeded wheat.
When Finesse works well, it will provide around 70 percent control of ryegrass. One would like for it to be higher, but that is normally good enough to let the wheat produce normal yield.
The main thing that must be considered in advance of using this herbicide is conventional soybeans may not be double-cropped. Either STS soybeans must be planted or the field must be summer-fallowed.
If you do chose to use Finesse, it provides a lot of garlic suppression and will absolutely clean out the winter broadleaf complex.
If you have a field with a severe ryegrass infestation that you are not going to plant to wheat, you can clean up a lot of the problem with a fallow-and-till program. You can also eliminate a couple of flushes of ryegrass prior to planting this way.
If you have a nice smooth seedbed prepared ahead of time, the major flush of ryegrass will emerge with the first nice cool snap in September. Then you can either kill it with a burndown herbicide and plant no-till or destroy it with preplant tillage.
If the field is to remain fallow, repeat the procedure and kill as many flushes as possible. Wheat can then be planted the next year with no ryegrass herbicide needed.
Also choose recommended varieties, seeding rates and fertility practices that will give the wheat the competitive edge.
Ford Baldwin, Practical Weed Consultants. e-mail: [email protected].