Impact of Cool Temperatures on Wheat Herbicides

Jim Martin, University of Kentucky Extension Weed Scientist



Snow covered wheat in late March

The cool temperatures we experienced this spring caused some wheat growers to delay herbicide applications in anticipation of better weather. Stress conditions such as cool temps tend to limit physiological process in plants; therefore, slowing the response of weeds to the herbicide. The desired level of control may eventually be achieved; however, in some instances the slower activity may allow time for some weeds to recover. The slower activity caused by environmental stress, such as cool temperatures, may also limit wheat’s ability to metabolize herbicides, thus resulting in injury. 

The immediate forecast doesn’t look favorable which prompts growers to ask “Do I spray or wait for better weather?”  

The logical choice would be to wait for improved conditions if the size and number of weeds are small. However, if the size or number of weeds dictates to spray, consider an herbicide option that has the greatest margin of safety and is effective on the weeds that are present. Cool temperatures may have less of an impact on controlling weeds that are highly susceptible than those that are marginally susceptible.  

The following are some tips to consider as we progress through the next few days,

• Harmony and Harmony Extra are examples of ALS- inhibitor herbicides that can injure wheat in cool wet soil conditions. Injury may also occur if wide fluctuations of day and nighttime temperatures occur prior to, or soon after, application It is not clear to what extent, if any, the injury observed for Harmony and Harmony Extra impacts wheat yield. The labels of these products recommend adding 2,4-D as a tank mix partner to limit the risk of injuring wheat from the ALS-inhibitor herbicides. It is important to recognize the safest time to use 2,4-D in wheat is when plants are fully tillered and prior to jointing. 

• Some growers may be tempted to include Clarity, Banvel, or other products that contain dicamba as a tankmix partner with other herbicides to enhance control of certain broadleaf weeds. Avoid using dicamba once wheat begins to joint in order to limit the risk of injuring wheat.

• When controlling wild garlic with Harmony, Harmony Extra, or similar generic products, allow time for plants to develop 2 to 4 inches of actively growing tissue. The new growth emerges from the base of the plants and not from the old leaves that have tip burn from cold temperatures.

Upcoming Events - Farm Succession Planning & Perry-Spencer Crop Day

Farm Succession Planning Series

Family farmers can get tips from Purdue University specialists on business communication and dealing with accounting and legal issues during a succession planning program offered at 10 sites in Indiana.

“Cultivating Strong Indiana Farm Family Relationships for Today and Tomorrow” will be offered in early 2013. The program is presented by Purdue’s Women in Agriculture and Farm Succession Planning teams in partnership with the North Central Risk Management Education Center.

Kelly Heckaman, Purdue Extension educator in Kosciusko County, said Indiana farmers and farm wives have asked educators for advice on handling their family businesses.

“In order to get estate planning started in families, they need to be able to communicate about it. And it’s an emotional topic, so it can be hard to get those conversations started,” Heckaman said. “The workshops will give families ideas on improving their conversations and skills to help them work through their problems and keep their families intact.”

Heckaman said the program is a collaboration between Extension and local communities, as organizers will invite local accountants and attorneys to speak on financial strategies. 

The first-session agenda topics are: “A Great Year to Farm: New Farmer Financial Skills,” “The Team Approach: Working Together Through Transition” and “Communicating for Success.”

The second session’s lineup is “Business Structure and Taxes,” “The Truth about Pre- and Post-Nuptial Agreements” and “Managing Conflict.”

Registration is $50 for individuals or $100 for families up to four members. Locally, the program will be offered at the Vanderburgh Co. 4-H Fairgrounds, 201 E. Boonville New Harmony Road, Evansville, on February 19 and 26, from 8:00 AM-12:00 PM CST. 

For more information, please contact Purdue Extension-Spencer County at (812) 649-6022 or nheld@purdue.edu.   Registration brochures are available online. 


Perry-Spencer Crop Day

The annual Perry-Spencer Crop Day program will be held Thursday, February 21 at 6:00 PM CST at the Fulda Sportsman Club. The program will feature Dr. Chuck Mansfield, Purdue Extension Agronomist, speaking on “Wheat Nutrient Management and Drought Effects on Soil Nitrogen”. The program will also feature an update on new fertilizer application regulations affecting farmers. 

The cost to attend is $5.00 per person, including the meal, and is payable at the door; however pre-registration is requested by February 14. PARP and CCH credit is available for an additional $10 fee. Two CCH credits will be available in categories 1, 14, and RT. 

For more information, or to register, please contact Purdue Extension-Spencer County at (812) 649-6022 or nheld@purdue.edu.

Upcoming Event - Ohio Valley Precision Ag Conference

Purdue Extension and University of Kentucky Extension will jointly host a Nov. 29 conference to teach farmers more about how precision agriculture systems could improve their bottom lines.

The Ohio Valley Precision Ag Conference will run from 9 a.m. to 2:30 p.m. (CST) at the Vanderburgh County 4-H Fairgrounds, 201 E. Boonville-New Harmony Road, Evansville. It will cover data management, implement systems technologies, and systems calibration and setup. It also will feature local precision agriculture companies and projects.

 

"The variety of technologies that farmers and industry representatives have to evaluate for on-farm use is staggering," said Kenneth Eck, Purdue Extension educator in Dubois County. "This conference will give folks a better understanding of what systems are available, how emerging technologies might mesh with producers' current systems, and how both farmers and agribusinesses can manage farm data for improved economic and environmental results."

 

The conference will start with a presentation titled "Data Utilization and Management with Precision Tools" by Betsy Bower and Troy Walker of Ceres Solutions.

 

Morning breakout sessions are:

• "RTK Accuracy" by Tim Stombaugh, associate professor of biosystems and agricultural engineering at the University of Kentucky.
• "Calibration Basics - John Deere" by Ben Carlisle, Wright-Stemle John Deere.
• "Variable Rate Seeding - Can You Do It and Do You Need To?" by Bob Nielsen, Purdue     Extension agronomist.

Afternoon breakout sessions are:

• A repeat of Stombaugh's "RTK Accuracy."
• "Calibration Basics – Trimble/Case IH" by Kevin Roy and Kristina Nadin, Hopf Equipment Case IH.
• "Economics of Investing or Upgrading: Old vs. New" by Greg Halich, associate Extension professor of agricultural economics at the University of Kentucky.

The conference also will feature a farmer panel discussion titled "What Do We Do With the Data and How is It Managed?" The keynote presentation will be "Precision Planting" by Gregg Sauder of Precision Planting Inc.

 

"This is the first time we've pulled together a program with so much of our expertise in one place," Eck said.

 

Conference registration is free, but reservations are required by Nov. 19. Participants can register online at http://tinyurl.com/pukyregister or by contacting any of the sponsoring Purdue Extension or University of Kentucky Extension county offices. Those counties in Indiana are Daviess, Dubois, Knox, Perry, Pike, Posey, Spencer, Vanderburgh and Warrick. In Kentucky they are Daviess, Henderson, McLean, Ohio, Union and Webster.

 

A flyer for the program is available here.

Plant Pathologist: Wheat Planted in Corn Stubble at Risk for Head Scab

More corn acres brought on by high corn prices in recent years could tempt winter wheat growers to plant the crop into corn stubble, but a Purdue Extension pathologist says the practice puts wheat at risk for head scab development.

Head scab, or Fusariam head blight, is caused by the fungus Gibberella zeae, also known as Fusarium graminearum, which is harbored in corn residue. In corn, the fungus causes ear and stalk rots, and in wheat can lead to yield loss and reduced grain quality. The disease also produces a mycotoxin called deoxynivalenol, also called DON or vomitoxin, which is toxic to humans and livestock.  <Read More>

2012 Wheat Variety Trial Results Now Posted

The results of the 2012 Wheat Variety Trials conducted in Spencer and Posey Counties are now available.  The 2012 plots contained 39 wheat varieties, replicated four times.  The results for both plots are located on the Purdue Extension-Spencer County website.   

Weekly Outlook - Update on Export Progress

Much of the attention in the crop markets is rightly focused on the potential size of the northern hemisphere crops. Still, the on-going pace of consumption is an important measure of demand strength and the likely level of year ending stocks. Here we focus on the U.S. export sector for wheat, corn, and soybeans.

For wheat, the 2011-12 marketing year ended on May 31. Cumulative export inspections for the year totaled 1.036 billion bushels, slightly above last month's USDA projection of 1.025 billion bushels. Through April, cumulative Census Bureau export estimates were about 4 million bushels less than cumulative inspections. Assuming that margin persisted through May, marketing year exports were about 7 million bushels larger than forecast. For the marketing year that began on June 1, the USDA has projected exports at 1.150 billion bushels. As of May 31, new sales plus unshipped sales from the past marketing year totaled 235.6 million bushels, near the level of sales of a year earlier. To reach the USDA projection, shipments will need to average about 22.1 million bushels per week this year. Export inspections during the first week of the year were reported at 21.5 million bushels.  <Read More>

Prospective Plantings Outlook 2012

The USDA Prospective Plantings and Grain Stocks Report is an annual report providing a first look at US farmers' planting intentions for the current crop year.  Soon after the 2012 report was issued this morning, Dr. Chris Hurt and Dr. Corinne Alexander of the Purdue Agricultural Economics Department presented a Prospective Plantings Outlook discussion webinar to help farmers, agribusinesses, and others involved in the grain industry make sense of the USDA report and its potential effects on grain markets.  If you missed the live presentation and would like to hear their analysis, a recorded version of the webinar is available here.  A high-speed internet connection is recommended for viewing.