Pre-emergence herbicides with residual activity are an important component of high-yielding cropping systems. They are used less frequently in wheat production compared to other cropping systems in Kansas, but residual herbicides applied prior to wheat emergence can be part of a good weed management system in wheat production.
Most residual herbicides labeled for pre-emergence application in wheat are Group 2 (ALS-inhibiting) herbicides, which are associated with herbicide resistant populations of kochia, marestail (horseweed), bushy wallflower, flixweed, henbit, and brome species in Kansas. Products in Groups 14 (the PPO-inhibiting herbicides) and 15 (the long-chain fatty acid inhibiting herbicides) are also labeled; however, they are generally more dependent on rainfall for activation than the Group 2 herbicides.
Herbicides without residual activity may be applied with or without residual herbicides in the weeks prior to planting wheat. Older products include the Group 2 herbicides Amber, Olympus, and Pre-Pare, as well as Group 4 (plant growth regulating) herbicides like 2,4-D, dicamba, or fluroxypyr. It is especially important to be aware of planting interval restrictions for Group 4 herbicides, which range from 10 to 45 days.
One new product is Pixxaro. Pixxaro is a combination of two Group 4 herbicides: fluroxypyr (Starane Ultra, others) and halauxifen (Elevore). It is labeled for control of emerged weeds both before wheat planting and after emergence when wheat is at the 2-leaf through flag leaf stage. The application rate for both timings is 6 fl oz/A.
When selecting pre-emergence herbicides for use in wheat production, keep in mind that many of these products are also labeled for use in emerged wheat. Unless using a planned split-application, avoid repeated use of products from the same herbicide group to slow the development of herbicide-resistant weed populations in your fields.
Table 1. Selected herbicides for pre-emergence or pre-plant applications in winter wheat.
|
Trade name |
Common name |
Herbicide group |
Application timing* |
Comments |
|
Amber |
Triasulfuron |
2 |
BD, PRE or POST |
Requires tank mix or sequential application of herbicide from different group |
|
Anthem Flex |
Pyroxafulfone + carfentrazone |
15 + 14 |
DPRE |
Plant wheat 1 – 1.5” deep |
|
Dicamba |
Dicamba |
4 |
BD |
Apply at least 45 days before planting wheat |
|
Finesse |
Chlorsulfuron + metsulfuron |
2 + 2 |
PRE, POST |
Suppression only of cheat, downy brome, and Japanese brome |
|
Kochiavore |
Fluroxypyr + bromoxynil |
4 + 6 |
BD |
Apply at least 30 days before planting wheat |
|
Olympus |
Propoxycarbazone |
2 |
PRE, POST |
Mix with glyphosate for BD |
|
Outrider |
Sulfosulfuron |
2 |
PRE, POST |
Apply after planting but before wheat emergence; |
|
Pixxaro |
Fluroxypyr + halauxifen |
4 + 4 |
BD, POST |
Do not use multiple applications or in successive years at the same site |
|
Pre-Pare |
Flucarbazone |
2 |
BD, PRE |
Mix with glyphosate for BD; |
|
Scorch |
Fluroxypyr + dicamba |
4 + 4 |
BD |
Apply at least 30 days before planting wheat |
|
Sharpen |
Saflufenacil |
14 |
BD, PRE |
Rainfall required for activation; |
|
Zidua |
Pyroxasulfone |
15 |
DPRE |
Rainfall required for activation; Plant wheat 1 – 1.5” deep |
*BD = burndown; PRE = pre-emergence to wheat and weeds; DPRE = Delayed pre-emergence application after wheat emergence; POST = post-emergence
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 and update use requirements.
Sarah Lancaster, Extension Weed Science Specialist
slancaster@ksu.edu