Post Emergent Herbicide Spraying for Sunflowers
There are limited choices for post emergent herbicides for sunflowers and the window is small. Understanding how to stage sunflowers will help you to not get caught off guard and apply your post emergent herbicide on time.
Factors to Consider
- The early stages are considered vegatative and start with a “V: followed by the number of leaves
- When first emerged out of the ground that is considered Vegetative Emergence (VE)
- Sunflower put on two leaves at a time (V2, V4, V6, etc)
- Growing degree days (GDD) for sunflower have lower end (44 vs 50 degree F) and higher end (no top end vs 86 degree F) than corn
- Plants with the Express® trait can be sprayed from V2 to pre-bud (safe bet to have it on by V10)
- The Clearfield® train can be sprayed from V2-V8 with the Beyond herbicide at 4 oz per acre. If you have Nuseed’s Clearfield Plus hybrid, N4H470 CLP, you can tank-mix in a methylated seed oil instead of non-ionic surfactant for a better weed kill.
- Zidua® is also labeled post-emerge, V2-V8, for residual control (needs to rain to activate)
With all of these products, consult your local agronomist or the label for proper rates and adjuvants.