Don’t Let Weeds Win: Management Strategies for Herbicide Resistance

Herbicide resistance limits the options available to control harmful weeds that are common in soybeans, but one or two ineffective herbicides is only the tip of the iceberg. Recently, waterhemp populations have shown resistance to six different herbicides: 2,4-D, atrazine, chlorimuron, fomesafen, glyphosate and mesotrione, leaving only dicamba and glufosinate available as viable chemical methods of control.

 

Farmers must begin to think of weed management more holistically and adopt broader methods of control, or resistance is just one of many problems that could arise.

 

The key to preventing resistance in one — if not multiple — herbicide modes of action is a diversified management strategy, including a combination of cultural, mechanical and biological controls.

 

 

Decisions like crop rotation, seed selection, planting and seeding rates, and row widths all can make or break your crop’s ability to suppress the reproduction ability of weeds and slow weed growth. Making proper management decisions gives your crop a competitive advantage over weeds.

 

 

Cover crops keep the ground covered while cash crops are not in the ground. By holding the soil in place, they prevent soil erosion. Cover crops also improve soil structure and enhance soil nutrients. While all of these are beneficial on their own, cover crops also contribute to weed suppression.

 

Tillage is also an effective means of weed control but should not be the first option in areas susceptible to wind or water erosion. If chosen as an approach to control, tillage methods should be changed regularly to prevent buildup of a particular species or group of weeds in the soil.

 

 

In-season management of weeds and herbicide resistance is important. Employing long-term strategies focused on delaying the evolution of resistance and reducing the population of weed seeds is also key to handling weeds. This means managing the seed bank and limiting weed seed production to keep resistant genes from spreading.

 

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.