Pre-Harvest Weed Control in Wheat

May 22, 2023

By Sarah Lancaster

This year’s short, thin wheat crop is generating some discussion regarding what to do with weeds at this point in the growing season. Broadleaf weeds that grow rapidly at the end of the growing season present several potential concerns, such as harvest difficulties, dockage problems, weed seed production, soil water depletion, and potential interference in summer crops planted after wheat harvest. Unfortunately, once wheat has reached the boot stage, there are no herbicide options until wheat begins to dry down and herbicides can be applied as harvest aids. The decision to spend resources on a herbicide application that will not directly influence crop yield is a difficult decision to make; however, pre-harvest applications may be beneficial this year.

Herbicides labeled for use as harvest aids in wheat are listed in Table 1. There are differences in how quickly they act to control the weeds, the interval requirement between application and grain harvest, and the level or length of control achieved. All of them will require thorough spray coverage to be the most effective. Paraquat is sometimes mentioned as a possible herbicide for pre-harvest application but is not labeled for pre-harvest treatment in wheat. Application of paraquat to wheat is an illegal treatment and can result in quarantine and destruction of the harvested grain, along with severe fines.

CROP

Figure 1. Weeds in wheat near harvest time. Photo by Dallas Peterson, K-State Research and Extension.

Table 1. Herbicides for use a pre-harvest weed control options in wheat.

*PHI = Pre-harvest interval, or days required between application and harvest.

For more detailed information, the “2023 Chemical Weed Control for Field Crops, Pastures, and Noncropland” guide is 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.

Source : ksu.edu

Video: Winter Canola Trial in Mississippi | Can It Work for Double Cropping? | Pioneer Agronomy

Can winter canola open new opportunities for growers in the Mid-South? In this agronomy update from Noxubee County, Mississippi, Pioneer agronomist Gus Eifling shares an early look at a first-year winter canola trial and what farmers are learning from the field.

Planted in late October on 30-inch rows, the crop is now entering the bloom stage and progressing quickly. In this video, we walk through current field conditions, fertility management, and how timing could make this crop a valuable option for double-cropping soybeans or cotton.

If harvest timing lines up with early May, growers may be able to transition directly into another crop during ideal planting windows. Ongoing field trials will help determine whether canola could become a viable rotational option for the region.

Watch for:

How winter canola is performing in its first season in this Mississippi field

Why growers chose 30-inch rows for this trial

What the crop looks like as it moves from bolting into bloom

Fertility strategy, including nitrogen and sulfur applications

How canola harvest timing could enable double-cropping with soybeans or cotton

Upcoming trials comparing soybeans after canola vs. traditional planting

As more growers look for ways to maximize acres and diversify rotations, experiments like this help determine what new crops might fit into existing systems.