ROOTED INRESEARCH THE STORY BEHIND-THE-STORY OF DACONIL


By Mike Fidanza, PhD


Daconil is perhaps the most recognized brand name among the turfgrass fungicides. Te active ingredient is chlorothalonil (Figure 1). Evidently, chlorothalonil is the third most used fungicide in the USA, behind sulfur and copper. Also in the USA, chlorothalonil is used mostly on peanuts, potatoes, tomatoes, and on other agricultural and horticultural crops, on managed turfgrass (i.e., golf courses, lawns and landscapes, athletic fields, sod farms), and as a preservative added to paints, resins, emulsions, and coatings.


Figure 1. Te chemical structure of chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile).


Te fungicide has a contact site-of-activity on the turfgrass plant; thus it is used to control diseases of the aboveground leaves and stems (Figure 2). Te mode-of-action (i.e., how the active ingredient affects the fungal pathogen) is the nonselective inhibition of enzyme


reactions at many sites within the fungal cells. Daconil WeatherStik, Daconil Ultrex, Daconil Action, Daconil ZN are branded chlorothalonil fungicides (from Syngenta). Examples of post-patent chlorothalonil products include: ArmorTech CLT 720XL (Advanced Turf ); Chlorothalonil Select (Albaugh/Prime Source); Previa (AMVAC); Chlorothalonil 720SFT and Chlorothalonil DF (Quali- Pro); Echo 720 (Sipcam Agro); and Pegasus (UPL).


But what’s the historical “back story” with Daconil fungicide? It all starts with Lee Kozsey. Some people who know Lee Kozsey, recently retired Syngenta sales representative, might think his brush with fame is that his second cousin is Don Shula, the famous Miami Dolphins coach and member of the NFL Hall of Fame. In the turfgrass industry, Lee is known for Daconil fungicide. Back in 1963, he was working in the laboratory that


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Figure 2. Daconil Action (fungicide) plus Appear II (potassium phosphite) plus Primo MAXX (plant growth regulator) is an effective treatment against cyanobacteria on an annual bluegrass putting green. Photo by Dr. Dean Mosdell


produced the very first pound of DAC-2787, the numbered compound that we know today as Daconil.


Lee grew up on the shores of Lake Erie, near Cleveland, OH. At age 10, with his strong work ethic attributed to a Hungarian and Finnish heritage,


he made five cents for each tree he planted at a local nursery. As a young man, he joined the Merchant Marines and “sailed” on Te Lehigh, a 600-foot-long iron-ore ship, in the Great Lakes that hauled ore from Duluth, MN, to Buffalo, NY. Te ore was used by the famous Bethlehem Steel Company. Of note, Lee now lives in Bethlehem, PA, with his wife, Lucille, in an area known as the Lehigh Valley. Lee didn’t have the opportunity to attend college, but he committed himself to learning throughout his career. In 1962, he was hired by the Diamond Alkali Company at their chemical plant at Fairport Harbor, OH, to work in Process Development, which was basically figuring out how to make newly discovered chemical compounds in the laboratory.


Lee worked on many different types of compounds and polymers that found their way into many consumer and industrial products, and he even received clearance from the Atomic Energy Commission when he worked on projects for the military. In 1961, head chemist Dr. Bob Battershell discovered DAC-2787 (“DAC” meaning Diamond Alkali Company, and “2787” meaning the two- thousand, seven hundred-and eighty-seventh compound synthesized). DAC-2787, which became Daconil fungicide, was made by “tweaking” DCPA (the active ingredient


TPI Turf News November/December 2023


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