Snow Mold Rating Season Has Begun!!

Whoopee! Snow mold rating season is in high gear for us. The first site we visited last week did not have a lot of activity, but our site in Stevens Point, WI was fantastic! The non-treated controls averaged 90% disease and a few products had some break through. For the most part however, most treatments did a good job preventing snow mold. We have not had a chance to enter the data and analyze it, but mixtures did exceptionally well. Products like Instrata at 9.3 oz, mixtures of Trinity/Insignia/Iprodione, Interface/PCNB, Chlorothalonil/Myclobutanil/Iprodione were just a few examples that performed exceptionally well. Interface is a new product from Bayer that will hit the marketplace some time this summer. Typically most products do well at our site in Stevens Point WI, but some of the excellent products and mixtures break down under the intense snow mold pressure at our site in Marquette, MI. We really do not know what to expect at our sites in Minnesota this year. I think both sites had substantial snow fall and cover, but one site is new and snow mold development at the other site is variable.



We do exhaustive testing of products for snow mold control and the main lesson is to combine fungicide families to achieve excellent results. Using just a single product with a single active ingredient is asking for break through. At least that is the case in the Upper Midwest. We do not have a single answer for what to apply for snow mold control because it depends on the pathogen normally observed, the courses budget and the threshold for damage. Since we do not have crystal balls to forecast the amount of snow during the winter months, combining active ingredients will ensure protection against Microdochium nivale and the two Typhula species. Combining a.i.'s usually works very well in our trials, especially those combos that are strong on ascomycetes and basidiomycetes. Pre-mixed products like Instrata and Interface usually accomplish this strategy. Chlorothalonil, propiconazole and fludioxonil are the a.i.'s in Instrata and Interface is a mixture of iprodione and trifloxystrobin, both mixtures have good activity on snow mold fungi. Pre-mixed products are not necessarily the best and golf course superintendents can develop their own mixtures. We have last year's snow mold data posted on the Turfgrass Diagnostic Lab's website, but if you are interested please check back in a couple weeks to see this year's data! For those in the Upper Midwest, we will be conducting Snow Mold Field days on April 14th (Minnesota??), 15th (Stevens Point, WI) and 16th (Marquette, MI). Please contact me (jkerns@wisc.edu) if you would like to attend. We do not charge for the events and we will have the specifics after next week. Stay tuned for photos from our more northern sites next week.