2022 Pest Alert #1 Snow Molds — Hello March, How Did Winter Go?, and Where are the Pesky Snow Molds?

Mild Winter Weather? Weather Summary Report for Chicago Area reporting by, Shehbaz Singh, MS

Winter (2021–22) in Chicago, Illinois was pretty mild versus the usual weather pattern for this area.

December. The highest temperature recorded was about 66°F in the month of December while, the lowest temperature recorded was -7° F in the month of January. Overall, the temperature in December ranged from 13 to 66° F which was higher than the normal temperature range for this month over Chicago area.

January. The temperatures in January were lower than the normal temperature range for this month.

February. The temperatures in February were quite similar to normal trends but in general towards its higher end. Significantly, temperatures during February, 2022 were much higher than last year.

Figure 1. Air Temperature: Blue bars = Chicago-area max/min temperatures recorded during winter 2021–2022.

Snowfall 2022 vs 2021. The snow accumulation this winter was about 30 inches. This was quite lower than the accumulation of about 45 inches last year. Most heavy snowfall occurs during January to mid-February.

Figure 2. Snow Accumulation: Green line = Comparison of snowfall for Chicago-area across winters of 2020–21 (left) and 2021–22 (right). Note: Blue line = 1978–79 represents highest snowfall ever (recordings to date).

Where are the Pesky Snow Molds? reporting by Derek Settle, PhD

We got a little. Pink snow mold (Microdochium nivale), also known as Microdochium patch and formerly as Fusarium patch, is the main snow mold that we see in the Chicago area. You see, it thrives under conditions of intermittent snow cover. That sounds like winter 2021–22 doesn’t it? A little further to the north, in say Wisconsin, it’s a whole different story where snow molds are PROBLEMATIC. I like that word. Anyhow, it means golf course superintendents in the U.S. that are closer to Canada have to be on their toes with fungicide programs. Because there are multiple snow molds, preventative programs applied in the fall must be designed with broad-spectrum ability. Otherwise some ugly turfgrass will appear about March. Speed of recovery will vary each year. It can be rapid or slow (depending on weather conditions). In a cool spring, damage via snow molds can be long-lasting. What will spring 2022 be like?

Research. Some of the best snow mold research in the country is conducted just to our north at the University of Wisconsin by Dr. Paul Koch et al. Check it out. https://tdl.wisc.edu/2020-2021-snow-mold-fungicide-research-reports/

Diagnostics. As we come out of the current 2021–22 winter in Chicago we are not seeing a lot of damage by snow molds and that just makes sense. We just didn’t get the long periods of snow cover required for things like gray snow mold/speckled snow mold or Typhula spp. (80+ days is necessary for development).

Image 1. Injury of a golf green surround following snow melt in Chicago. Microdochium or pink snow mold most probable. Damage is observed is minor and quick recovery in spring will occur. Scott Pavalko, Mar 1, 2022

Image 2. White fluffy mycelium is typical of pink snow mold (Microdochium nivale). Scott Pavalko, Mar 1, 2022

Image 3. Close up image of putative pink snow mold (Microdochium nivale). Scott Pavalko, Mar 1, 2022

Fungicide Recommendations. Click on link below. For pink snow mold/Microdochium patch see page 18. For gray snow mold/speckled snow mold see page 20. http://www2.ca.uky.edu/agcomm/pubs/ppa/ppa1/ppa1.PDF