Chemical Company Mergers
May Affect Herbicide Market

By Tracy Sayler

The consolidation of chemical companies may mean fewer herbicides available on the market for crop producers, according to Bev Durgan, University of Minnesota extension weed specialist.

For example, Bayer’s acquisition of Aventis CropScience is one change that may affect the Northern Plains, since Aventis has been an active player in small grain markets. “Bayer has also been a player in the small grains market.  One of the outcomes we tend to see with consolidation is less herbicides being researched and marketed.  We are also seeing a number of products dropped from the market place, either because of these mergers or other reasons.”

According to 2000 industry statistics, Syngenta had about 21.3% of the U.S. ag chemical market, followed by Monsanto at about 18.5%.  Bayer and Aventis, combined, would have been third with about 15.5%, followed by Dow, 12.5%; BASF, 11.7%; and DuPont, 6.7%, reports Iowa Farmer Today.

Durgan adds that the move to broader spectrum herbicide programs focused on crops tolerant to such herbicide chemistries as glyphosate (“Roundup-Ready”) or imidazolinone (“Clearfield”) help simplify crop management.  However, these systems will also affect the way herbicides are researched and marketed.

Hoelon is one herbicide that will no longer be available in the market after this growing season, says Durgan. 

Puma is one herbicide product which has grown in use.  “It had a lot of advantages, with a wide window of application. It controls both foxtail and pigeongrass, has no varietal restrictions and can be used on both spring wheat and barley.  The one problem we are seeing with Puma is the development of herbicide resistant wild oats in some areas. I want to caution you against using Puma too much, too often, too many years in those fields.  If you are seeing a weed control failure—wild oats in fields that you can’t control, but that you have controlled in past years—you should consider rotating to a herbicide with a different mode of action.”

Achieve had been used on a number of spring wheat acres in the past, but because of crop injury potential, the product is no longer labeled for use on spring wheat in South Dakota, Minnesota, and some areas of North Dakota (east of N.D. Hwy 281, and Dickey, LaMoure, Stutsman, Foster, Eddy, Ramsey, and Towner Counties).  “It is still labeled for barley, and the control of Achieve last year in barley was very good,” says Durgan.

Discover is another herbicide that is increasing in use. “It has some advantages over Puma, and some disadvantages.  Discover has a wide window of application: applied to wheat from two leaf to the fourth tiller, to control foxtail from one to five leaf, and wild oats, one to six leaf.   It can be tanked mixed with almost all the broadleaf herbicides except 2, 4-D ester. Discover must always be applied with the DSV adjuvant.”

“One problem is that it is not as effective on yellow foxtail as Puma. Also, although Discover is in a different chemical family than Puma, they are both ACC inhibitors, so their mode of action is similar. So Discover is not one of the products that you want to use if you are rotating with Puma, as you may still risk the development of herbicide resistant wild oats,” says Durgan.

Last year was the first full year of use for Everest for wild oat and pigeongrass control. It is an ALS inhibitor, similar to Assert.  It offers good green foxtail control and fair control of yellow foxtail.  It can be applied on one to six leaf wheat, to control one to four leaf foxtail and one to six leaf wild oats. It needs to be applied with a non-ionic surfactant, and it should always be applied with a broadleaf herbicide for crop safety.”

Durgan says there has been some crop tolerance issues with Everest, particularly in the northern part of N.D., when applied under adverse conditions or late.  “The label says it can be applied up to six leaf wheat, but that is a bit late.  I would apply only up to four to five leaf wheat. Also to prevent injury, tank mixing it with 2, 4-D will add some safening to that product. So you just need to be aware of some of the precautions with Everest, but it is one you can use in rotation with Puma or Discover to help prevent the potential of herbicide-resistant wild oats.”

Everest does have recropping restrictions: Nine months for sugar beets, potatoes, barley and canola, and 11 months for field peas. It is not labeled in barley. “Discover is not labeled in barley either because of some injury potential,” says Durgan.

Bronate Advanced is a new formulation of Bronate on the market.  Bronate Advanced is more concentrated and offers improved performance on tough broadleaf weeds. “The real change compared to Bronate is just the formulation and the use rate.  Make sure you look at which one you have when you are looking at rates,” she says.

When Pigeongrass Control Is (And Isn’t) Justified

By Bev Durgan, University of
Minnesota Extension Weed Scientist, durga001@umn.edu

Making the decision on whether to control foxtail (pigeongrass) in small grains is not always easy. Research has shown that infestations of foxtail often will not decrease wheat and barley yields; however, heavy foxtail infestations can cause harvest problems (especially when straight combining) and can cause dockage when the grain is delivered to the elevator.

There are some situations when the cost of a herbicide treatment for foxtail control is not justified. They would include:

•  When foxtail infestations are light -- less than 20 plants/ft2.

•  When the foxtail emerges after the crop is in the 3 to 4-leaf stage. This is especially true for barley. Once the small grain is in the 3 to 4-leaf stage, it can usually out compete foxtail, thereby making a herbicide treatment unnecessary. However, if the foxtail population is heavy (30 plants/ft2 or more) control may be needed.

•  Moisture stress is another factor that complicates this situation. Weeds will generally cause greater yield losses under drought conditions, therefore foxtail control would be more important in droughty fields.

•  Spring wheat variety is also a factor. Research has shown that the spring wheat  variety 2375 does not compete well with foxtail. Therefore, it is more important to control foxtail in 2375 fields than in fields planted to other varieties.

Making the decision on whether to apply a herbicide for foxtail control is more complicated when the foxtail is emerging with or shortly after the small grain crop.  If the foxtail infestation is heavy, and is emerging with the small grain, consider harrowing or rotary hoeing as soon as possible. If a harrow or rotary hoe is not an option, then consider a herbicide. If wild oats are also in the field, the herbicides of choice are Hoelon, Cheyenne, Tiller, Puma, Discover, and Everest. Hoelon needs to be applied to small foxtail (1 to 3-leaf).

If wild oats are not present, then Stampede EDF can also be considered.  If the foxtail infestation is light to moderate, then it may be possible to wait and see if the crop will be able to out compete foxtail. If foxtail is still a problem by the time the small grain is in the 5 to 6-leaf stage, then Tiller, Cheyenne, Puma and Discover can be used for control.