U of G UPDATE
Coming Out of the Winter That Wasn’t
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uperintendents here in Ontario are no strangers to long, cold winters. Although not as extreme as what is experienced in other parts of the country, winters here result in snow molds, ice sheets, thaw-refreeze events and extended snow cover. Each year seems to be a guessing game as to how the turf will fare come spring. In my six years here in Ontario, there are two things I have learned about winter injury. One, there will always be a huge range of damage occurring through the province from little or no damage to greens being wiped out. The second thing I have learned is that winter preparation is just as much about feel and experience as it is about science. All that said, this is the oddest winter I have experienced since moving to Canada. In a year like this one, I have no idea how the greens will look once the season begins and we really don’t know what Mother Nature has in store for us. The focus of this article is to discuss possible outcomes of a mild winter and to try and predict what might happen, but more importantly, what you can do to mitigate any damage that does occur on your greens this year.
Ice damage Each year, a number of superintendents ask me whether or not they should tarp their greens. In areas where the weather is somewhat predictable and less variable, it is a much easier question. In the Prairie provinces where snow cover is shortlived and winds are often howling across the turf, the use of permeable covers makes sense to prevent winter damage from cold temperatures and desiccation. In areas of Quebec
22 Green is Beautiful • Winter 2012
Figure 1. Pink snow mold (Microdochium nivale) on a mixed creeping bentgrass/annual bluegrass collar (Photo courtesy Sean Jordan)
Figure 2. Damage likely resulting from crown injury in late winter (Photo courtesy John Bladon)
where it gets very cold and where ice formation is quite common, often a hybrid type of tarp that has elements of permeability, insulation and impermeability is used. But here in Ontario, it’s a really tough call. Snow does a wonderful job of insulating turf, but we never really know for how long sufficient snow cover will remain. More often than not, we are plagued with prolonged ice sheet formation as we experience extended periods above freezing followed by deep freeze periods where ice forms. In winters such as these, the use of impermeable covers can certainly prevent some damage, as long as they are applied properly, allowing for air exchange while preventing water flow onto the green. For the most part, however, the use of covers in Ontario is not a necessity and while they can be helpful, they may not always be worth the cost and potential risk of dehardening the plant tissue.
nobody wants to take chances is where snow molds are concerned. We may not always have the ideal conditions for gray snow mold (Typhula incarnata, T. ishikariensis) but we quite often have the ideal weather for Microdochium patch (aka Fusarium patch/Pink Snow Mold) (Microdochium nivale) (Fig 1.). Either way, applying a preventative fungicide for these diseases is critical in Ontario as either disease can wipe out a green if left unchecked over the winter. The most commonly used fungicide for these diseases, quintozene, is no longer available and this has led to some difficult management decisions. There are several other products on the market, but there are some trade-offs regarding relative efficacy for each of the potential diseases. In addition, timing is a bit more critical as many of the products need to be taken up by the plant for maximum effectiveness. It becomes difficult to predict when the plant is still able to absorb the product while being close enough to hardening off to ensure that the fungicide will not be metabolized too early. This particular winter, it is difficult to predict whether
Snow mold prevention With the new IPM regulations in place, golf courses are showing a reduction in preventative pesticide applications, but one place where