Some questions have recently come in looking for herbicide options for corn in later vegetative stages. Adequate pre-emergence herbicides were applied; however, excessive rainfall and sandy soils resulted in weed emergence. While early-season weed control is critical to protect yield potential, in some situations, late-season weed control may be needed to protect yield, prevent harvest difficulties, and reduce additions to the weed seed bank.
Table 1 lists products that can be applied to corn over 12 inches tall to control emerged weeds. Note that some of these products recommend or require drop nozzles to reduce crop injury and get better spray coverage on weeds that are shorter than the crop. Also of note, strategies for more successful herbicide applications in high temperatures were discussed in an eUpdate article published on June 13.
Table 1. Herbicides labeled for corn over 12 inches tall to control emerged weeds.
|
Herbicide |
Product |
Maximum |
Comments |
|
Glufosinate |
Liberty, others |
V6 |
|
|
Tolpyralate |
Shieldex |
V6 or 20 inches |
Can mix with Tough to enhance control |
|
Clopyralid |
Stinger, others |
24 inches |
Fair to good pigweed control |
|
Topramezone |
Armezon, Impact |
V8 |
Can mix with Tough to enhance control |
|
Pyridate (6) |
Tough |
V8 |
Can be used to enhance Group 27 herbicides |
|
Mesotrione (27) |
Callisto, others |
V8 or 30 inches |
Can mix with Tough to enhance control |
|
Glyphosate |
Many |
V8 or 30 inches |
RR2 hybrids use drop nozzles 30 to 48 inches |
|
Nicosulfuron (2) |
Accent |
36 inches |
Use drop nozzles >20 inches |
|
Tembotrione (27) |
Laudis |
V9 |
Can mix with Tough to enhance control |
|
Carfentrazone (14) |
Aim |
14 leaves |
Use drop nozzles > 8 leaves |
|
Bromoxynil |
Moxy, others |
tasselling |
Fair pigweed control |
|
Dicamba |
Clarity others |
tasselling |
Fair to good crop safety |
|
DiFlexx |
V10 |
Good crop safety |
|
|
Status |
V8 or 30 inches |
Good to excellent crop safety |
|
|
2,4-D (4)
|
Amine or ester |
tasselling |
Use drop nozzles if corn >8 inches |
|
Enlist One |
V8 or 30 inches |
|
For more detailed information, see the “2024 Chemical Weed Control for Field Crops, Pastures, and Noncropland” guide available online at https://www.bookstore.ksre.ksu.edu/pubs/CHEMWEEDGUIDE.pdf or check with your local K-State Research and Extension office for a paper copy.
The use of trade names is for clarity to readers and does not imply endorsement of a particular product, nor does exclusion imply non-approval. Always consult the herbicide label for the most current use requirements. Users should read and follow all label directions.
Sarah Lancaster, Weed Science Extension Specialist
slancaster@ksu.edu