Changing Of The Guard October 6, 2010 By Jim Skorulski

The loss of PCNB will result in significantly higher costs for fungicides to manage microdochium patch, gray and speckled snow mold diseases.

The first real signs of fall are here, with reports of scattered frost in the North, the arrival of pumpkins, squash and cornstalks at road side stands, and the color changes taking place outside. Just about everything has been two weeks ahead of schedule this year. Considering the summer we just experienced, the shorter days and cooler nights, and a less intense schedule, provide an opportunity to heal from the summer grind and begin preparing for the winter.   

Winter preparation on many northern golf courses has become more complicated with the recent loss of PCNB fungicide. As the backbone of many fairway management programs, the fungicide was a reliable and inexpensive option to manage the snow mold pathogens. The recent restriction on PCNB pertains to product being sold, so any product on hand can still be used as in the past.  The good news is there are a number of fungicide chemistries that perform equally, if not better, than PCNB formulations. The bad news is that the cost for those products may be 3-4 times higher, depending on the product and the applied rates.  

The impact of the loss of PCNB will be felt mostly at northern golf courses that experience higher disease pressure due to a longer duration of snow cover. Those areas often experience more than 60 days of snow cover, with much higher levels of Microdochium patch and gray snow mold (Typhula incarnata), and possibly speckled snow mold (Typhula ishikariensis). Speckled snow mold usually is more of a problem in the snowbelt regions, and, unlike gray snow mold, the damage is more persistent and difficult to recover from.     

Field trials in the New England, the North Central and the Northwest regions consistently show that combinations of at least two different fungicide chemistries are required to suppress snow mold when disease pressure is high. The performance of the fungicides varies based on disease pressure (length of snow cover) and the pathogens that are present. Generally, courses that experience a longer duration of snow cover can expect higher disease pressure and will require the more effective and higher-cost fungicide combinations for satisfactory control. Areas that are further south in the region (where snow cover is typically 40 days or less) may be able to get by with the less-expensive fungicide options, or take their chances and forego the late fall fairway fungicide application. That decision will be based on the cost of the application and the willingness of the golfers to tolerate some fairway damage in the spring.

In any event, the dependency on PCNB for snow mold management programs is ending. The sudden ‘stop sale’ order imposed by the EPA may be temporary, but the likelihood of the product being reregistered in the future is low. Life without PCNB will just be a bit more complicated and a lot more expensive. More information about alternative management options can be found in the Green Section webcast “An Update on PCNB and Alternatives” found at:

The effectiveness of alternative fungicides for snow mold can be seen in the UMASS 2009-2010 Snow Mold Filed Trials at following link:  /content/dam/usga/pdf/imported/course-care/2010_snow_mold_jung.pdf

Northeast Region Green Section- Dave Oatis, Director; Adam Moeller, Agronomist Jim Skorulski, Senior Agronomist