As summer weather looms ahead, farmers must keep a close watch on both the forecast and the calendar date to ensure they manage dicamba technology appropriately.

The temperature on the thermometer is another area of importance when following the dicamba product label. Applicators must understand air temperature restrictions before applications, especially as temperatures begin to rise throughout the state.

The Illinois Department of Agriculture (IDOA) included language in the 2020 Special Local Needs Labels that stated the following regarding air temperature restrictions:

DO NOT apply this product if the air temperature at the field at the time of application is over 85 degrees Fahrenheit or if the National Weather Service’s forecasted high temperature for the nearest available location for the day of application exceeds 85 degrees Fahrenheit.

For the most accurate temperature forecast, the applicator should check the local National Weather Service (NWS) website on the day of the proposed application. The forecast is obtained by entering the zip code of the nearest town to the proposed field of application.

IDOA will require consultation of www.weather.gov no earlier than one calendar day prior to the date of application. IDOA recommends the applicator print a copy of the forecast to include with the application records.

Here are a few examples concerning air temperature influences:

  • On the day of application, the forecasted high temperature for the day per the NWS website is 84 degrees and the air temperature at the time of application is measured – as required by the product label – by the applicator to be 83 degrees. The application may proceed.
  • In another scenario, the high temperature for the proposed application date per NWS website is forecast to be 87 degrees at 5 p.m. The applicator measures the air temperature at the field at 10 a.m. to be 76 degrees. This is a DO NOT APPLY situation, because the forecast high for the day of application exceeds 85 degrees.
  • In a third scenario, the high temperature for the proposed application date per NWS website is forecast to be 83 degrees at 5 p.m. The applicator measures the air temperature at the field at 2 p.m. to be 86 degrees. This is a DO NOT APPLY situation, because the air temperature at the time of application exceeds 85 degrees.

Just as applicators take note of projected temperatures, they must also only apply dicamba within the allotted window of application. Spraying beyond the cut-off date puts the applicator off-label, regardless of who is making the application.

The IDOA included language in the 2020 Special Local Needs Labels that included a condition stating:

DO NOT apply this product after June 20, 2020.

It is important to note that the requirement of the federal label also factors in here as well such that over-the-top application of dicamba on soybeans is prohibited 45 days after planting.

Given weather variables, there could be a limited window of opportunity to spray this season. Farmers must be proactive and perceptive as they steward this technology and should not be tempted to spray during less-than-ideal situations.

From the Editor: This series of articles is written for the purpose of providing IFB members education on the requirements surrounding usage of dicamba on soybeans as they head into the 2020 growing season.