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On June 04, 2020

To Scout For Chilling Injury In Newly Planted Corn And Soybeans.

The general consensus is that for proper germination of corn and soybean seeds, we should have a minimum soil temperature of 50 degrees Fahrenheit. But what happens when we plant into soils that haven’t yet reached that threshold or when a period of cold, wet weather follows soon after planting? 

Extension Agronomist Dwane Miller explains under those conditions we certainly risk susceptibility of the seed to imbibitional chilling injury. Imbibition is the uptake of water by a newly planted seed. In corn this happens usually during the first 24-48 hours after planting, assuming the soil is moist. For soybeans, imbibition usually occurs within 24 hours of planting. 

The seed swells as it takes on moisture and its cell structure is damaged. Under warm conditions the cell damage is quickly repaired during the germination process and plant growth continues normally. However under cold conditions the cell membranes are less flexible and the damage to the cell is worse and the repair of the damage is slower or may stop completely. This can lead to leaking of the cell contents and ultimately the death of the seed. 

Much of the research is not clear-cut as to how long the seed needs to be exposed to sub-50 degree soil temperatures for this damage to occur. But if the seed is planted and soil temperatures are below 50 degrees during the first 24-48 hours chilling injury is possible. Once seeds have imbibed their needed water, if soils then drop below 50 degrees, emergence may be delayed, but chilling injury should not be a problem. 

At this point, there is really nothing that can be done for corn and soybeans that are already in the ground. If you have planted corn or soybeans and experienced a cold rain and/or prolonged cold soil temperatures, you will want to scout your fields for possible emergence problems. For more information on chilling injury, check out these articles from Purdue University https://www.agry.purdue.edu/ext/corn/news/timeless/ImbibitionalChilling.html, and from The University of Nebraska: https://cropwatch.unl.edu/chilling-injury-corn-and-soybeans. 

To Choose The Right Dicamba Or 2,4-D Products To  Use As Burndown In Xtend Or E3 Soybeans

Extension Agronomist Dwight Lingenfelter has received questions about the use of certain dicamba products (Clarity, Banvel, etc.) regarding preplant applications prior to planting Roundup Ready 2 Xtend soybeans and 2,4-D product use in Enlist E3 soybeans. In short, they were asking if Banvel, for example, can be sprayed in the burndown mixture and then immediately plant Xtend soybeans. 

The answer is no. Whether it is Clarity, Banvel, or most other generic dicamba-containing products, the label states that at least 28 days plus 1 inch of rainfall/irrigation is necessary before any kind of soybean is planted if, 1 pint of product is applied. The labels of the specific products may vary slightly, but state similar information. 

Since Xtend soybeans are not specified on their labels this longer wait period must be applied. Currently, the only dicamba products that can be legally applied near planting or over-the-top in Xtend soybeans are Enginia, FeXapan plus Vapor Grip Technology, Xtendimax with Vapor Grip Technology, and Tavium plus Vapor Grip Technology.  

Similar regulations hold true for the use of 2,4-D products in Enlist E3 soybean. Enlist E3 soybean varieties can be planted immediately after an application of Enlist One or Enlist Duo (choline salt) in a burndown program. Any other 2,4-D product (LV4 ester, amine, etc.) must adhere to the 7-15 day wait period before planting depending on use rate. Once the E3 soybeans emerge only Enlist One or Duo can be applied as an in-crop application, no other 2,4-D products can be sprayed over-the-top and using them would be in violation of the Technology Use Agreement.

In either the Xtend or E3 system, certain herbicides, adjuvants, and other pesticides can be tank-mixed with the core auxin herbicide, however you must first check the specific websites to be sure what combinations are allowed.

Also, before any application can be made all the guidelines must be followed, especially to reduce off-target spray drift to other crops which is a significant concern. Other guidelines include prescribed nozzle types, boom heights, sprayer speed and wind speed limits. Also, depending on the landscape setting, field buffers must be included if susceptible crops are present and downwind at the time of application. 

Guidelines for using Xtendimax, Engenia, FeXapan, and Tavium can change periodically as new information is acquired. Refer to their labels and websites for additional information and updates online by Bayer, BASF, Corteva, and Syngenta. Application information for the Enlist E3 soybean system can be found here: https://www.enlist.com/en/herbicides/application-guide.html

Finally, Enlist E3 and Xtend soybeans are not cross tolerant to the auxin herbicides. If you apply 2,4-D post to Xtend soybean it will severely injure or kill them. The same is true if you spray dicamba on E3 soybeans. Currently, Xtend soybeans are tolerant to dicamba and glyphosate and E3 are tolerant to 2,4-D choline, glyphosate, and glufosinate (Liberty). Other conventional soybean herbicides can be used in either system.

Quote Of The Week: “It pays to know the enemy — not least because at some time you may have the opportunity to turn him into a friend.” Margaret