By Joseph M. Vargas Jr.
Years ago, controlling snow mould was easy and simply involved applying mercury fungicide in the fall. Then, mercury fungicides were banned and controlling snow mould became a little more difficult. There were still quintozine products for control, which made things a bit easier; however, this author did not like to see them used on greens because of their root-pruning properties.
Quintozine was a good fairway product and was inexpensive, but it has now been banned. Fortunately, many researchers felt this restriction was coming and began testing existing products as replacements. What they found was to get adequate snow mould control of the three dominant pathogens—Typhula incarnata, Typhula ishikariensis, and Microdochium nivale—three-way fungicide combinations were needed. Many different combinations were found to work, but the reliable tank mix is generally chlorothalonil and a DMI fungicide, which work well on the Typhula species, and then QoI or iprodione fungicide added to assist with control of Microdochium nivale.
There is a three-way product with a different combination of fungicides (i.e. propiconazole-fludioxonil-chlorothalonil). All three are necessary to control the snow mould complex. Additionally, it only requires one annual application. Resistance develops quickly when repeated applications are made throughout the season against a single fungal pathogen. We are dealing with multiple pathogens requiring different chemistries for control.
Read the full article: Controlling Turfgrass Diseases