Why Rotate? An Herbicide Strategy.

If it ain’t broke, don’t fix it, right? Unfortunately, this is the approach many LCO Managers and Golf Course Superintendents take with regards to herbicide programs. I get it. As an LCO owner/applicator myself there are a handful of reasons why you continue with what’s been working. Such as… Simplicity and familiarity of sticking with what you have historically been doing, satisfaction with the results to date, the learning curve and potential risks associated with new programs. Fair enough, and I’m not suggesting you completely throw away a competent herbicide program that’s provided satisfactory results but here are the bullet points of why you should rotate:

  1. Weed resistance prevention. From Poa to Sedges to other weeds, we are running out of modes of action to control some of our most troublesome weeds. Rotating different “modes of action” does work and should be implemented to keep current herbicides relevant and effective in the future.
  2. Weed shifts. As good as your current program is, there are weeds it does not control – especially pre-emergent programs. And after several years of the same program’s use, you will begin to see the weeds it doesn’t control become your new weed problem spectrum. You are selectively cultivating new weed problems by not rotating to a program that controls them.
  3. To keep your current program viable. I’m not suggesting discarding the previous program. I am recommending rotating out to another equally efficacious or better herbicide program and alternate them to keep both working at peak performance. Ideally with different mode of action.

To illustrate my points above, let’s take a prominent herbicide that many have been using continuously for several years to control Poa and various other weeds, Specticle®. It’s a very good herbicide and one of the last pre-emergent herbicides left to control Poa resistant to other modes of action. Let’s preserve it (point #1 and #3) by rotating to another option like Coastal® herbicide that contains 3 different modes of action for pre-emergent control of Poa. And unlike Specticle®, Coastal® has 2 modes of action for post-emergent control of Poa. Coastal® also controls many weeds Specticle® does not (point #2), like Wild Garlic, Dollarweed and Purple Deadnettle (stickers) among others. Both products have their advantages and disadvantages, but this is a great example of two different herbicides that can be rotated without a drop off in broad-spectrum weed control. And by doing so address Resistance prevention, Weed shifts and future program viability.


By Michael Prudhomme, Utopia Yards LLC (LCO Owner/Applicator)

Specticle® is a trademark of Bayer Environmental Science USA

Coastal™ is a trademark of Sipcam Agro USA