Recap of 2010-2011 Snow Mold Trials

It seems funny to talk about snow mold on April 26th, but thanks to mother nature there isn't much else to talk about in the Midwest. We have experienced a very cool, wet spring so far this year. Just last week northern areas of Wisconsin received 7 to 9 inches of snow! We were very lucky that the dates we picked for our snow mold field days were nice, well at least the weather was nice at two of the locations. We have five locations for our snow mold trials: Brainerd, MN, Les Bolstad Golf Course in St. Paul, MN, Grant Park Golf Course in Milwaukee, WI, Sentryworld Golf Course in Stevens Point, WI and Wawonowin Golf Club in Champion, MI. We travel to these different locations in order to test fungicides against as many snow mold pathogens as possible.

For this post I thought I would summarize the a portion of the results from Sentryworld. The picture at the upper right hand portion of this post was taken by Dr. Derek Settle at the CDGA and shows the level of disease at this trial. Although the non-treated controls averaged 74%, this is misleading because a single control somehow escaped with only 22% disease. The primary pathogen observed at this location was Typhula ishikariensis. Once again we observed that mixtures of fungicides that incorporate multiple modes of action worked very well. The graph below depicts a sample of results from this trial. There were 90 entries and the remaining treatments as well as the other sites can be accessed through our webpage soon. Mixtures with Torque (tebuconazole) worked very well, especially a mixture of Torque and Affirm (polyoxin-D). An interesting new fungicide is Velista, which is a carboximide fungicide (other members of this family are Prostar and Emerald). It does have activity against snow mold fungicides on its own, but not enough to provide acceptable control. When Velista was mixed with a DMI (in the figure Banner MAXX is presented) and chlorothalonil, these mixtures performed well.

Instrata at 9.3 oz performed well in our trials as it has for many years. Concert provided significant reductions in snow mold even when applied by itself at the 8.5 fl oz rate. This year we had a number of Civitas mixtures in our trials and they performed well. The product applied alone will not control snow mold, but when applied as a tank mix component results were quite good. Finally, Interface continued to show good efficacy against snow molds. Interface by itself did reduce snow mold severity, but not to a level that we consider acceptable (<5%). Yet, adding Daconil dropped snow mold severity to acceptable levels.

Now that the season is finally getting going, I will start posting once a week again. We have initiated a number of very interesting research projects that I will post about this year as well as updates on what we see in the TDL, so stay tuned!

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.