COURSE CARE
Tried And True April 18, 2011 By Bob Vavrek

Pink snow mold and Microdochium patch are caused by the same pathogen at different times of the season. Pink snow mold is relatively easy to diagnose just after the snow melts, but Microdochium patch can occur anytime later in the season when conditions are favorable for disease activity and often can be mistaken for dollar spot.  

There’s not much to like about the extended period of exceptionally cool, wet weather this spring unless you are the fungus that causes Microdochium patch (pink snow mold).  No doubt, the thunder that accompanied heavy rain and sleet in Milwaukee must be music to the ears of this and other pathogens that cause a variety of cool temperature turf diseases.

Spring green-up at golf courses across the Region is nearly a month behind the early start to the season last year.  No doubt, it is difficult to think about firing up the sprayer when only a handful of rounds have been played and a considerable amount of turf on the course is still semi-dormant. 

The fact that it may be approaching six months since the greens have been treated with any fungicide should provide turf managers ample encouragement to replace nozzles, calibrate the sprayer, and begin a thorough scouting program for disease activity.   Keep in mind that turf treated with fungicides, particularly contact materials, just prior to snowfall last year may have already been exposed to sunlight for six to eight weeks by now, so there is no reason to expect any residual protection.

Yet, significant springtime Microdochium activity still comes as a surprise to some --- it shouldn’t, but it does.   Maybe the expensive tank mix of multiple fungicides at high rates made last fall lulls us to sleep with the unreasonable expectation that the protection should certainly last until we are good and ready to spray the next season.   Carry-over effect was likely when high rates of heavy-metal-based fungicides, such as PMAS, were used in days gone by, but that is not the case with current fungicide options.  Highly effective short-residual fungicides have completely replaced the old mercury and arsenic materials, and keeping on our toes with respect to scouting for diseases is a very small price to pay for making the environment a high priority on golf courses.

Controlling Microdochium patch during spring is not overly difficult or expensive once positive identification is made.  For example, a standard application of iprodione has, and continues to be, a tried and true treatment for this disease and has often been the first fungicide used on greens by experienced superintendents during spring at many courses across the north-central tier of states.   Never overlook this disease with the mindset that warm, sunny weather is sure to arrive soon, because an active infection can eat turf right down to the bone within a few days when the weather conditions are just right. 

Golf is trying hard to rebound in a sluggish economy.  The modest expense of treating greens for disease during spring can be a good investment when many nearby courses are competing for a fixed or dwindling number of potential members and green fees.  Remember, word gets around quickly with respect to a course with bad greens during the spring, and golfers always tend to exaggerate the amount of injury to a putting surface.  No one ever drives an extra five or ten miles to play a golf course because the fairway striping is unique or the tee markers are always set correctly, especially when gasoline begins to eclipse the $4/gallon mark.  It’s all about the greens, and a bad first impression of your course can last all season.

Bottom line...underestimate the potential for Microdochium disease to cause significant injury to slowly growing greens during cool, wet springtime weather and it will bite you on the gr ass

Source:  Bob Vavrek,rvavrek@usga.org or 262-797-8743