Limited Choices for Post Emergent Herbicides

There are limited choices for post emergent herbicides in sunflowers and the window is small. Understanding how to stage sunflowers will help you not get caught off-guard and apply your post-emergent herbicide on-time.

Factors to Consider

  • The early stages are considered vegetative and start with a “V” followed by the number of leaves
  • When first emerged out of the ground that is considered Vegetative Emergence (VE)
  • Sunflowers put on 2 leaves at a time (V2, V4, V6, etc)
  • Growing degree days for sunflowers have a lower end (44 vs 50 deg F) and higher end (no top end vs 86 deg F) than corn

Action Plan

  1. Plants with the Express® trait can be sprayed from V2 to pre-bud (safe bet to have it on by V10)
  2. The Clearfield® trait can be sprayed from V2 to V8 with the Beyond herbicide at 4 oz per acre. If you have Nuseed’s new Clearfield Plus hybrid, N4HP470, you can tank-mix in a Methylated Seed Oil instead of a Non-ionic surfactant for a better weed kill.
  3. Zidua is also labeled post-emerge V2-V8 for residual control (needs a rain to activate). Zidua won’t kill what has emerged

Summary

With all of these products, consult your local agronomist or the label for proper rates and adjuvants

#winningwithsunflowers

Resources

https://www.ag.ndsu.edu/extensionentomology/recent-publications-main/publications/A-1331-sunflower-production-field-guide

https://www.ag.ndsu.edu/weeds/weed-control-guides/nd-weed-control-guide-1/wcg-files/6-Snfl.pdf