New Granular Fungicides for Turf

Historically, fungicides on granular formulations have never been used frequently on turf. With the exception of late fall snow mold applications and damping off applications to the seedbed, there weren't many situations in which granular fungicides were recommended.

Two things were limiting the usefulness of granular fungicides: a limited selection of products and low-tech carriers that weren't very effective for foliar disease control. As a result, my standard recommendation has always been that if you want good disease control,  you should spray instead of spread. As an example, look at the tall fescue plots to the left that were both treated with triadimefon at the same rate of active ingredient per acre. Triadimefon is not a very effective brown patch fungicide to begin with, but the sprayable formulation (Bayleton) is much more effective that the granular formulation (Fungicide VII).

Things changed quickly, though, and today many more products are available on granular carriers, including recent products like Armada, Disarm, Heritage, and Headway. Several others are currently being tested as experimentals. Furthermore, these new products take advantage of modern granular formulation technology that makes them more effective against foliar diseases by increasing foliar absorption of the active ingredient.

We've evaluated a number of these new granular formulations, mostly against brown patch in tall fescue in a lawn care scenario. I will include a couple of examples here. I would summarize by saying this: these new granulars are more similar to their sprayable counterparts for brown patch control, but generally their efficacy is a erratic and they require more frequent applications. I still think that if you have the capability to spray, it's still better to spray. But these products provide more options to turf managers in situations where spray applications are not possible or practical.

Another possible advantage of a granular formulation is for control of root diseases like summer patch, spring dead spot, fairy ring, take-all patch, etc. To control these diseases most effectively, you obviously want the active ingredient to be in the root zone. With a granular, you can make the application and then water in later at your convenience, rather than having to worry about running the heads right behind the sprayer before it dries on the foliage. While we haven't tested these newer products against root diseases, we always used to see very effective spring dead spot control from granular formulations of Rubigan.

I'd like to hear some comments from our readers on this topic: What are the advantages and disadvantages of these granular formulations in your experience? If you are using these products, how and for what are you using them?