Soybean herbicide trait stacks are becoming more complex with multiple sites of action to help farmers gain the upper hand on weeds that are becoming increasingly difficult to control. Some of the chemistries used can cause significant damage to sensitive crops if the proper steps are not taken to ensure complete sprayer cleanout. As little as a thimble (1/16,384th of the full rate) of dicamba left in the volume of a 1,000-gallon sprayer tank system is enough to cause symptomology on nonresistant soybean plants. The higher use of post emergent herbicide applications, increasing trends of tank mixing with adjuvants, and complex plumbing in sprayers and handling systems can all increase the chances of cross contamination when switching between crops or traits. The important steps and possible problem areas are shown below:
- Triple rinse the entire sprayer (Figure 1).
- Fill the sprayer tank ½ full of water then flush.
- Fill the sprayer tank ½ full of water, add an approved tank cleanout agent and circulate for 15 minutes, then flush.
- Fill the sprayer tank ½ full of water, then flush.
- Examples of places pesticide residue can hide in a sprayer even after a thorough triple rinse (Figure 2).
- Nozzles, screens and filters should be removed and manually cleaned with warm soapy water or with an approved cleaning agent (Figure 3).
- Sprayer “dead ends” and end caps should be removed and flushed during each cleaning.
- Just a couple of best practices that can help avoid many of these sprayer contamination issues are:
- Start with a clean sprayer, even a small amount of AMS left over from the previous tank load can overwhelm the VaporGrip® Technology in XtendiMax® herbicide and increase the possibility of off-target movement.
- During hot summer days, sprayer hoses expand, causing open pores which absorb active ingredients and trap those possible contaminants as temperatures drop. Load and spray the product in a short amount of time, especially in higher-temperature conditions.
- Do not allow a load of dicamba-based product to sit in a sprayer overnight because the longer chemistries are left in the tank, the greater the chance the mixture may settle out, making them harder to get the mixture back into solution. The active ingredients may be absorbed into hoses or settle in the sump or other dead spots within the sprayer.
- If you have multiple sprayers, nurse tanks and delivery hoses, creating dedicated sprayers, nurse tanks and delivery hoses for specific sets of active ingredients can eliminate some of the above described issues.
In conclusion, low-volatility dicamba-based products like XtendiMax® herbicide with VaporGrip® Technology, a restricted use pesticide, are effective weed control agents in soybeans. Following application requirements and performing sprayer system cleanouts as described in this article can help you avoid damaging a susceptible crop the next time you use your sprayer. If you have further questions about this topic, your Channel Seedsman is a good resource for walking you through the issues and helping you discuss and find solutions that fit your farm operation.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Performance may vary, from location to location and from year to year, as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on the grower’s fields. XtendiMax® herbicide with VaporGrip® Technology is part of the Roundup Ready® Xtend Crop System and is a restricted use pesticide.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. It is a violation of federal and state law to use any pesticide product other than in accordance with its labeling. XtendiMax® herbicide with VaporGrip® Technology may not be approved in all states and may be subject to use restrictions in some states. Check with your local product dealer or representative or U.S. EPA and your state pesticide regulatory agency for the product registration status and additional restrictions in your state. For approved tank-mix products and nozzles visit XtendiMaxApplicationRequirements.com. Channel® and the Arrow Design® and Seedsmanship At Work® are registered trademarks of Channel Bio, LLC. VaporGrip® and XtendiMax® are registered trademarks of Bayer Group. ©2020 Bayer Group. All rights reserved.