PCNB Developments and Snow Mold Management

Oct. 22, 2010

Developments Surrounding PCNB and Snow Mold Management

Mr. Joseph Rimelspach, The Ohio State University / Dr. Jim Kerns, University of Wisconsin

There are many questions being asked about the recent EPA decisions regarding PCNB. There are many concerns and inpiduals want to start making plans for alternative at least for this year. The following is an update from Dr. Jim Kerns, turfgrass pathologist at the University of Wisconsin, posted Wednesday, September 8, 2010. If you have additional questions please contact us.

Late this summer there were changes made about PCNB products. Basically the US EPA had reason to believe that there were impurities in the pesticide that could have toxicological significance. Consequently the US EPA ordered a stop sale, use or removal order effective immediately for all products containing PCNB or derived from Technical Grade PCNB. The company who manufactures Technical Grade PCNB sued the US EPA in order to have the stop sale order temporarily lifted, but was denied on September 3rd.

It is imperative to understand that this is not a permanent halt on PCNB distribution and sales. The company is seeking other alternatives within the legal system and it was emphasized in the aforementioned article that this issue is fluid. However, I do think it is important to think of an alternative to PCNB for this year. This is difficult situation because PCNB is a great snow mold product and it is inexpensive. I do think there are alternatives though. Not to beat a dead horse, but the best thing to do is to review Wisconsin snow mold trials at the following site (http://tdl.wisc.edu/pdf/Snow%20MoldReports2010_Live/index.html)

One thing to consider is thiophanate methyl. This a.i. is frequently overlooked, but is an excellent snow mold product. Products such as Instrata and Interface have performed exceptionally well in our trials, but some course may have the budget to apply these to fairways. Mixtures of chlorothalonil, iprodione and propiconzole or chlorothalonil, iprodione and myclobutanil have performed well in our trials. Other a.i.'s that stand out are triticonazole (Trinity, BASF and Triton FLO, Bayer) and metconazole (Tourney Valent BioSciences). Unfortunately I do not know what these products cost, so my suggestion is to sit down with our reports and your local salesperson to figure out what will work for your course and budget.

This is rather unfortunate development for this year considering the condition of the economy.

Following are some recommendations based on research done at the University of Wisconsin. These are based on having both Gray and Pink Snow Mold being present in the turf:

  1. Good: 2 oz T-methyl + 5.5 oz chlorothalonil (most of Ohio this should work, in Cleveland / snow belt areas will probably see significant break-through)
  2. Better: 4 oz iprodione + 5.5 oz chlorothalonil (most of Ohio as well, but significant break-through in Cleveland possible)
  3. Best: 4 oz Iprodione + 5.5 oz chlorothalonil + 2 oz of propiconazole applied as a microemulsion formulation or 0.72 oz applied as the concentrated EC formulation
  4. Excellent: 3 oz of propiconazole (microemulsion) + 0.3 to 0.5 oz of Medallion (excellent for high pressure areas, but fairly expensive!)
  5. Supreme: 7 to 9 oz Instrata + 4 to 6 oz Interface + 2 oz of propiconazole (again as the microemulsion formulation)

We will keep you informed if there are additional developments in this area.

bygl 1 10-22-10 bygl 2 10-22-10
Pink Snow Mold in Creeping Bentgrass Lawn Gray Snow Mold in Tall Fescue lawn after winter of 2009-2010, Columbus, Ohio