Pre-Seed for #Seed25

Herbicide resistance has become a growing challenge for farmers and effectively tackling it requires a fresh approach. For years, the advice was simple: rotate your herbicide groups. Then came tank-mixing, where multiple modes of action were applied together in one application. Now, research shows that herbicide layering could be a more effective way to manage resistance risks and stay ahead of stubborn weeds. 

What Is Herbicide Layering? 

Herbicide layering is about using different herbicides at multiple times during the season to tackle weeds at every stage of their lifecycle. It’s like creating a multi-layered defense for your fields, ensuring that tough, herbicide-resistant weeds like kochia, cleavers, and wild oats populations are managed and seed production is limited. 

For example, you might start with a pre-seed herbicide that combines multiple groups, then follow up with a different set of groups for in-crop spraying, and finish with another application after harvest. This method doesn’t just tackle today’s weeds—it helps prevent future resistance. 

How Does It Work? 

How Does Herbicide Layering Work? 

It starts with a pre-seed application. This step usually combines a burnoff product to kill early emerged weeds with a soil-applied herbicide to prevent new weeds from emerging.  

For example, Focus^® herbicide (Groups 14 (carfentrazone)and 15 (pyroxasulfone)) works with glyphosate to control tough annual broadleaved weeds like kochia while creating a protective barrier in the soil against germinating grass and broadleaved weeds. 

The pre-seed application can be followed by an in-crop/pre-harvest application to tackle any weeds that slipped through the cracks or emerged later. Finally, a post-harvest fall treatment targets perennials and winter annuals, setting your fields up for success in the spring.   

This layered approach doesn’t just manage the weeds you see now—it helps delay resistance in your fields. 

Why Layering Makes Sense 

Dealing with resistant weeds like wild oats, cleavers, and kochia can feel like an uphill battle. Herbicide layering offers several benefits that make it a game-changer: 

• Slows Resistance: Using different modes of action at other times makes it harder for weeds to adapt. 

• Covers All the Bases: Hitting weeds at multiple growth stages keeps them from stealing vital resources like water, sunlight, and nutrients. 

• Boosts Performance: Pre-emergent herbicides do the heavy lifting early, making in-crop herbicides more effective. 

• Reduces Future Problems: Stopping weeds before they go to seed reduces weed pressure in the years to come. 

Getting Started with Herbicide Layering 

If you’re ready to give herbicide layering a try, here are a few steps to help you get started: 

1. Know your weeds: Early-emerging annuals vs. perennials require different approaches. 

2. Choose the right timing: Early spring soil-applied products work for cool-weather weeds; pre-emerge soil-applied products work well for weeds that come up with the crop; post-harvest burnoff applications of systemic products are effective on winter annuals and perennials. 

Combine with Other Strategies 

While herbicide layering is a powerful tool, it works even better as part of an integrated weed management plan. Adding practices like crop rotation, cover crops, and harvest weed seed control can enhance results and reduce your reliance on herbicides over time. 

Don’t Rely on Glyphosate Alone 

Glyphosate is great for killing emerged weeds but doesn't offer any soil residual activity. Adding a soil-applied herbicide to your pre-seed glyphosate application can keep weeds at bay through the critical early growth stages, giving your crop the best chance to thrive. 

By targeting weeds with a combination of products at different times, herbicide layering is a smarter way to manage resistance and protect yields. It's all about staying one step ahead of the weeds and ensuring your fields are ready for success now and in the future.