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More on the DMIs and Bermudagrass Greens


It is often said that good research raises more questions than it answers. Maybe the same can be said about blog posts? And no, I am not referring to Megan's California Gurls post from last Friday. (Side note: My main motivation for posting today was to bury that thing as quickly as possible. No pun intended.)

In last week's post about Torque for spring dead spot and fairy ring control, I casually mentioned that tebuconazole can injure ultradwarf bermudagrass putting greens. Since then, I've had a lot of questions about Torque and other DMIs and their safety on bermudagrass greens. It's a complex issue, and one that we don't have all of the answers to. Your questions will motivate us to do more research on this next year.

Although many of the newer DMI fungicides on the market are more safe on cool-season putting greens, they can be more injurious on bermudagrass greens. Looking at the graph to the left, you see that applications of Trinity (triticonazole) and Lynx (tebuconazole) caused severe damage to Tifeagle bermudagrass, Bayleton caused a slight reduction in quality, and Banner and Eagle had no effect. This is almost exactly the opposite of what you would see on creeping bentgrass or annual bluegrass putting greens.

Of course, application rate and time of year influence the amount of injury that is caused by DMIs, with the greatest injury caused by high rates, repeated applications, and high temperatures. You will notice that in the above example, we made 5 applications in a row at high label rates during the heat of the summer. No wonder some of them caused injury!

However, don't make the mistake of thinking that that all of the DMIs are safe on the ultradwarfs in the fall and spring or if you're only making one application. As an example, refer to my post from last fall entitled Effects of DMI Fungicides on Bermudagrass Putting Greens. In this example, we saw pretty significant phytotoxicity from some of the DMIs even after one application when temperatures were relatively mild.

I don't mean to scare everyone away from using the DMIs. We never see issues on bermudagrass fairways or athletic fields, and some of the DMIs are perfectly safe on greens. Just choose your products wisely and don't jump on the newest products right away just because they are new!

4 Responses to “More on the DMIs and Bermudagrass Greens”

John Kaminski said...

That was a "Like" for burying Megan's post, not for your DMI post...although that was good too.

Megan said...

Come on, that was the greatest post of all time! John is just mad that I didn't make HIM Snoop.

Nice info on the DMI injuries, though, and I'll try to rein it in next time with the celebrities, etc, but sometimes it's hard to resist...

Bermuda Grass said...

Wow!!!! so nice blog. I like the Green everywhere. I tell to every one Go Green and live Green. Thanks so much...........

Anonymous said...

I want to use Rubigan as poa control on my overseeded and non-overseeded greens. How do you think it would rank for bermudagrass injury with the DMI's above?

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