HRAC (Herbicide Resistance Action Committee) classification groups herbicides by their specific mode of action, using a letter or number code printed on the label — and rotating between different groups, not just different product names, is what actually protects against resistance building up over repeated seasons of use.
Why This Classification Exists
Two herbicides can have completely different brand names and even different active ingredients while still working through the same underlying biological mechanism. If you rotate between products that are actually in the same HRAC group, you're not achieving genuine resistance management, even though it looks like you're using "different" herbicides.
How to Find the Group on a Label
Look for a letter or number code, often near the active ingredient information, sometimes explicitly labeled "HRAC Group" or "Mode of Action Group." This code is what actually matters for rotation purposes — not the product's brand name or even its specific active ingredient percentage.
Pro tip: Keep a simple written record of which HRAC group you've used on a given area each season. Memory alone is unreliable across multiple seasons and multiple products, and a genuine rotation strategy depends on knowing your actual history, not just an impression of "I've been switching things up."
Why Rotation Actually Works
| Approach | Resistance Risk |
|---|---|
| Same product, every application | High — consistently selects for the same resistant survivors |
| Different products, same HRAC group | Still high — the underlying selection pressure is identical |
| Genuinely different HRAC groups, rotated | Meaningfully lower — different mechanisms target different vulnerabilities |
A Practical Rotation Approach
Rather than switching products randomly, deliberately alternate between two or more genuinely different HRAC groups across seasons on the same land. Our Glufosinate 10% SL and Ammonium Glyphosate 15% work through different mechanisms, making them a genuine rotation pair rather than two options from the same underlying group.
Watch out: Don't assume "I bought a different brand this time" means you've rotated modes of action. Many products across different brands share the same underlying HRAC group — check the actual classification code, not just the packaging or marketing name, before considering your rotation genuine.
Frequently Asked Questions
What does HRAC group mean on a herbicide label?
It's a classification code indicating the herbicide's specific mode of action — the biological mechanism it uses to kill the plant — which is the relevant factor for resistance management, not the brand name.
Does switching herbicide brands count as rotation?
Not necessarily — different brands can share the same underlying HRAC group and mode of action, so genuine rotation depends on checking the actual classification, not just the product name.
How often should I rotate herbicide groups?
Many resistance management programs recommend alternating groups each season or application cycle on the same land, rather than using the same group repeatedly over multiple consecutive treatments.
Compare our full herbicide range to build a genuine rotation strategy for your land.