Table 2.2-12. Maximum corn and weed sizes for delayed preemergence/early postemergence herbicide applications
See specific herbicide label(s) for additional information on application.
- This type of application generally is used when weather conditions preclude use of standard preemergence program.
- For most products, do not apply in liquid fertilizer if corn has emerged.
- Poor control from residual herbicides may result if annual grasses such as foxtail and panicum have emerged at time of application; tank-mix with product that controls emerged grasses.
- Delayed preemergence/early postemergence programs can work well with herbicide-resistant corn hybrids now available (e.g., Roundup Ready, Liberty Link, Clearfield-CL or IMI)
- When tank-mixing with other pesticides, follow the most restrictive product label.
| Herbicide | Maximum corn size | Maximum weed size |
|---|---|---|
| Verdict |
before emergence |
before emergence |
| Zemax |
30 inches (8-leaf) |
3-inch broadleaves; before grass emergence |
| Zidua |
early postemergence |
before emergence or by tank-mix partner |
|
||
| Atrazine | 12 inches | 1.5 inches |
| Axiom | before emergence | before emergence |
| Balance Flexx | 2-leaf (V2) | 1 true leaf stage |
| Balance Pro/Radius | before emergence | before emergence |
| Bicep II Magnum, Cinch ATZ + Prowl | 4-leaf or 2 collars | 1- to 2-leaf |
| Bullet or Micro-Tech + atrazine | 5 inches | 2-leaf |
| Clarity or Marksman + Dual or Lasso EC | 3 inches | 2-leaf grass |
| Clarity or Marksman + Outlook | 8 inches | 1-inch grass |
| Corvus | 2-leaf (V2) | <2 inches (in general) |
| Define/Radius | before emergence | before emergence |
| Dual + Marksman |
3 inches | 2-leaf |
| Dual II Magnum (Dual + atrazine), Bicep II Magnum, Bicep Lite II Magnum, Ci | 5 inches | 2-leaf |
| Dual II Magnum + Clarity | 5 inches | 3-inch pigweed |
| Dual or Intro + atrazine, Bullet | 5 inches | 2-leaf |
| Fierce |
before emergence |
2-inch broadleaves; by tank-mix partner for grasses |
| Guardsman Max/G-Max Lite | 12 inches | 1.5 inches broadleaves; before grass emergence |
| Halex GT | 30 inches | 4 inches |
| Harness, Harness Xtra², Degree, Degree Xtra | 11 inches or by tank-mix partner | before broadleaf emergence, 2-leaf grasses or by tank-mixed partner |
| Instigate | 2-leaf (V2) |
3 inches |
| Lexar EZ |
12 inches | 3-inch broadleaves; before grass emergence |
| Lumax EZ |
12 inches | 3-inch broadleaves; inconsistent on emerged grasses |
| Marksman + Prowl | 2-leaf | 1-inch grass |
| Outlook | 12 inches | before emergence or by tank-mix partner |
| Prequel | before emergence | before emergence |
| Princep | before emergence | before emergence |
| Prowl + Accent¹ or Prowl + Accent + Beacon¹ | 6-leaf | see herbicide labels |
| Prowl + Atrazine, or Prowl + Banvel | 12 inches | 1 inch |
| Prowl + Beacon¹ | 6-leaf | depends on weed (see Beacon label) |
| Prowl H2O | 30 inches | before weed emergence |
| Python WDG | 2 inches | before weed emergence |
| Resolve | 12 inches | 2-inch grasses; 3-inch broadleaves (in general) |
| Surestart, TripleFLEX | 11 inches | limited activity on 1-inch broadleaves; before grass emergence |
| Surpass, FulTime, TopNotch, or Keystone³ | 11 inches or by tank-mix partner | before emergence or by tank-mix partner |
