Some species of weeds are challenging to control, such as the Palmer amaranth. When left untreated, this aggressive weed can have a detrimental impact on grain sorghum, but pre-emergence herbicides can help. Now, experts at Kansas State University’s Department of Agronomy are sharing their insight with agricultural producers who are attempting to leverage post-emergence herbicide.
Atrazine can be effective on sensitive populations of Palmer amaranth when used with other herbicides. It can be applied with crop oil or surfactant, but farmers should always observe rate limits in their specific area.
Aim, also known as carfentrazone, can be used on grain sorghum between four inches and boot stage. It requires sufficient coverage for maximum effectiveness, but it is worth noting that it is likely to burn sorghum leaves.
2,4-D can help limit weeds, but crops may respond with rolled leaves, lodging, and brittle stems. Dicamba can spur a similar crop response, especially if applied in hot and humid conditions. This response can be limited by applying lower rates with atrazine, Aim, bromoxynil, or Huskie.
Bromoxynil may be a better option, as the crop response it typically evokes is less severe. However, it is relatively ineffective in controlling Palmer amaranth larger than four-leaf. Furthermore, complete spray coverage is necessary for the best results.
Huskie, also known as pyrasulfutole and bromoxynil, may be the most effective option when mixed with atrazine. That being said, agricultural producers should still be aware that there is a potential for leaf burn, especially if mesotrione was previously applied.
More information on herbicides and weed control practices can be found by visiting Kansas State University’s Department of Agronomy website.