ISSUE 2   May 22, 2008

NEW EXTENSION SUGARBEET WEED SCIENTIST JOINS NDSU

Hello! My name is Jeff Stachler. On May 6, 2008, I joined the Plant Sciences Department at NDSU as the Extension Sugarbeet Weed Scientist. I will be attempting to fill the "large shoes" of Dr. Alan Dexter. I will be responsible for extension and research activities pertaining to weed control in sugarbeets in Minnesota and North Dakota. This position continues to be funded as a joint position between North Dakota State University and the University of Minnesota.

I was raised on a diversified crops and livestock farm from West Central Ohio, near the Indiana border. I received an Agronomy B.S. degree from The Ohio State University and an M.S. degree from Michigan State University in Weed Science in 1995. My Masterís research focused on controlling wild carrot in no-tillage corn and soybeans and the discovery of resistance to 2,4-D in wild carrot in the Great Lakes Region. After completing my M.S., I accepted a position with The Ohio State University as Weed Science Extension Program Specialist for agronomic crops in September 1995. My responsibilities there included extension programming, research of problem weeds, and teaching. This position allowed me to work toward my Ph.D. while working as an Extension Weed Specialist. My Ph.D. research was on the discovery of resistance to glyphosate and ALS-inhibiting herbicides in marestail/horseweed in Ohio and glyphosate-resistant giant ragweed in Ohio and Indiana.

I look forward to working with everyone in North Dakota and Minnesota in the coming years! If you have any questions or comments, I can be reached at jeff.stachler@ndsu.edu or 701-231-8131.

 

UPBEET PLUS GLYPHOSATE MIXTURE APPROVED

DuPont Chemical Company recently received approval of a 2(ee) label for the mixture of Upbeet with glyphosate applied to glyphosate-resistant sugarbeets. Upbeet may be applied at 0.25 to 1.0 ounce per acre in combination with glyphosate. The label suggests adding a nonionic surfactant (NIS) at 0.25 %v/v plus ammonium sulfate (AMS). This herbicide combination should improve the control of velvetleaf compared to glyphosate alone and may improve the control of additional weed species. The mixture of Upbeet plus glyphosate is the only mixture currently labeled for glyphosate-resistant sugarbeet. This mixture can ONLY be applied to glyphosate-resistant sugarbeets.

 

CONTROL OF DANDELION IN NO-TILLAGE BROADLEAF CROPS

Several calls have been received about the control of dandelion in no-tillage broadleaf crops. The ideal time to control dandelion with herbicides is in the fall. Control of dandelions with herbicide applications in the spring is possible, but usually variable and with fewer options.

In soybeans, the most effective preplant treatment for the control of dandelions is glyphosate plus 2,4-D ester plus a cloransulam-containing herbicide (Authority First, FirstRate, Gangster, or Sonic). The user must carefully weigh the value of the cloransum (FirstRate) component as it is a long residual herbicide and rotation to barley, canola, flax, sugarbeet, and sunflower is 30 months plus a bioassay.

Mixtures of glyphosate plus 2,4-D ester can effectively control dandelion, however, control tends to be less consistent and is dependent upon the rate of each product. The minimum rate of glyphosate and 2,4-D ester in this mixture should be 0.75 pounds acid equivalent per acre (lb ae/A) and 0.5 pounds active ingredient per acre (lb ai/A), respectively. Higher rates of glyphosate and 2,4-D ester usually improves the consistency of control, especially rates of 2,4-D ester at 1.0 lb ai/A. Planting of soybeans must be delayed after preplant application of 2,4-D ester. Soybeans can be planted 7 days after application of 2,4-D ester at 0.5 lb ai/A (usually 1 pt/A, although some 2,4-D formulations are more concentrated) and usually 30 days after application of 2,4-D ester at 1.0 lb ai/A. The 2,4-D formulation, E-99, can be applied at 1.0 lb ai/A 15 days prior to planting of soybean.

Glyphosate applied alone at 1.5 to 2.25 lb ae/A can control dandelion. This is especially important if soybeans have been planted but have not emerged or growers are not willing to delay planting of soybeans. Preplant application of Valor plus glyphosate plus 2,4-D ester can provide rapid activity on dandelion, but dandelions are more likely to regrow compared to previously mentioned treatments. Ammonium sulfate must always be included with glyphosate applications.

Application of effective herbicides prior to or at the time of flowering of dandelions can provide somewhat effective control of seedling dandelions, because viable seeds have not been produced. However, if dandelion seed has been produced prior to preplant herbicide applications, the inclusion of Gangster should provide the most effective residual control of seedling dandelions. Valent claims Valor will control seedling dandelions, however limited research data is available to support their claim. Cloransulam applied alone provides only limited residual control of dandelions.

After emergence of glyphosate-resistant soybeans, only two options exist for fair to excellent control of dandelions. Those options include glyphosate applied at 1.5 lb ae/A followed by glyphosate at 0.75 lb ae/A or glyphosate applied at 1.1 to 1.5 lb ae/A plus FirstRate at a minimum of 0.3 ounce per acre.

Control of dandelions in other no-tillage broadleaf crops (sunflower, flax, etc.) hinges upon the success of preplant herbicide applications. Since 2,4-D ester is not available for use in preplant applications of these crops, the proper rate of glyphosate is key to successfully controlling dandelion. Apply glyphosate at 1.5 to 2.25 lb ae/A prior to planting of other broadleaf crops. Glyphosate may be applied after planting, but it must be applied prior to crop emergence and control of dandelion may be reduced due to plants being damaged during the planting process.

Jeff Stachler
NDSU Extension Sugarbeet Weed Scientist
jeff.stachler@ndsu.edu


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