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.
|VE Stage (cotyledons only)||V2 Stage (2 leaves)||V6 Stage (6 leaves)|
FACTORS TO CONSIDER
• The early stages are considered vegetative and start with a “V”, followed by the number of leaves.
• Vegetative Emergence (VE) is when the plant is first emerged out of the ground with cotyledons only and no true leaves.
• Sunflowers grow two leaves at a time (V2, V4, V6, etc.).
• Sunflowers have a lower end (44 vs 50 degrees F) and higher end (no top end vs 86 degrees F) of growing degree days than corn.
1. Plants with the Express® trait can be sprayed from V2 to pre-bud (to be safe, apply it by V10).
2. The Clearfield® trait can be sprayed from V2 to V8 with the Beyond® herbicide at four ounces 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® will not kill any weeds that have already emerged.
With all of these products, consult your local agronomist or reference the seed label for proper rates and adjuvants.