By: Keith Perl, President
Snow mold is arguably one of the toughest diseases to manage. If you do not prepare to prevent it, prepare for a battle in the spring for recovery. A preventative approach is critical to great control. Even with the best practices, there are many variables that can affect control and ultimately create very undesirable turf in the spring. Required spring maintenance practices are already time consuming. Do not add to your list by “short-changing” your preventative approach to snow mold control this fall.
In our area, the biggest concerns are gray snow mold and pink snow mold. Gray snow mold requires snow cover, whereas pink snow mold can be active in cool, damp conditions. Either type can be much more aggressive when the snow falls on unfrozen ground.
In the not too distant past, PCNB was the “go to” product for snow mold control. A few years ago, the EPA canceled registrations on the chemistry for about 2 years. During this ban of PCNB, turf managers reached for other options. (It should be noted that PCNB is again available and AMCAC (the producer) is promoting PCNB and other products that include 2 chemistries.)
We have reviewed several years of data from many snow mold test sites over the past several years and the following are general recommendations. We would encourage you to discuss this topic with your representative, as there are many options and price ranges of combinations that are currently available.
In reviewing the trial results, it was observed that the best control was obtained by combining several different classes of chemistries. As the inputs were decreased, cost was decreased, and control also decreased. In some cases, the decrease was substantial, especially if you are trying to protect highly maintained surfaces such as greens. Repair of these areas is harder to manage in the spring and it is recommended that your investment in these areas is not short-changed.
At the very minimum, you should be using a contact fungicide such as chlorothalonil and another product that demonstrates very good activity against pink snow mold such as iprodione. From there you could add a strobilurin or a DMI, or both. A four-way combination repeatedly produced the best results.
When using these products, it is not as critical to wait as long as possible. In fact, it is widely believed that making the application a little earlier has the benefit of allowing the material to get “into” the plant, allowing the application to be more effective and last longer. Another general rule is that once the application is made, mowing should cease until spring. If winter golf is allowed at your facility, consider rolling to smooth surfaces. If you need to mow, repeat applications may be necessary.
In closing, it is highly recommended that you do not skimp on your most valued assets (the greens). If your budget allows treating other areas, treating with as few as 1 or 2 products will likely be sufficient to at least keep this troublesome foe from becoming severe and requiring major inputs in the spring.
Please consult your Walker Supply Territory Manager for more details.