Department of Plant Biology and Pa thology Foran Hall, Room 366 Rutgers, The State University of New Jersey 59 Dudley Road New Brunswick, NJ 08901

- 8520 turf.rutgers.edu Clarke@aesop.rutgers.edu

848

- 932

- 6295
Fax: 732

- 932

- 9377

October 15, 2014 Mr. Ricardo Jones Chemical Review Manager Risk Management and Implementation Branch 1 (RMIB1) Pesticide Re

- evaluation Division (PRD) Office of Pesticide Programs US Environmental Protection Agency

Dear Mr. Jones :

I am the Extension Specialist in Turfgrass Pathology at Rutgers University

. My area of expertise is in mycology focusing on ectotrophic root

- infecting fungi

, as well as selected foliar pathogens such as Magnaporthe, Sclerotinia, and Colletotrichum . I have had a research, teaching, and extension appoint ment at Rutgers for the past 3 2 years

. Part of my job is to evaluate fungicides for their ability to control economically important turfgrass diseases and to make fungicide recommendations to turfgrass manage rs within the context of sound integrated disease management practices. My goal has always been to encourage turfgrass managers to reduce fungicide inputs on turfgrass sites whenever possible.

It has recently come to my attention that the EPA is re

- evalu ating fosetyl

- Al for use on turfgrass and is considering reducing the allowable amount of active ingredient for this product for the control of turfgrass diseases

. I have evaluated fosetyl

- Al (the product for turf is called Chipco Signature) for well over 20 years; first as an experimental material and then as a labeled turfgrass fungicide since 1996. Throughout this time, I have found fosetyl

Al to be an extremely effective fungicide for the control of anthracnose and Pythium diseases on turf with a docu mented record of safety when used according to label recommendations

. Anthracnose and Pythium Blight/Root Rot are two of the most economically important diseases of turf . Anthracnose has become one of the most destructive diseases of annual bluegrass p utting greens in North America and Pythium diseases affect all species of cool

season turfgrasses during the summer months in the US. Reducing the allowable amount of fosetyl

- Al on turf would render this material ineffective for the control of these diseases (the current label rate of fosetyl

- Al on turf is 17.6 lbs AI per acre per month)

. As you know, fungicide resistance has become a major problem in the turfgrass industry. As a result

, many fungicide chemistries are no lo nger effective against selected turfgrass diseases such as anthracnose and Pythium due to the development of fungicide resistance. In particular, the majority of golf course superintendents in the US can no longer rely on the benzimidazoles, dicarboximide s, and QoIs to control anthracnose, and many have experienced reduced sensitivity to the DMIs for the control of this disease. Because of its mode of action, no cases of fungicide resistance have been documented for fosetyl

- Al on turf diseases. As a resu lt, turf managers rely on fosetyl

- Al and chlorothalonil as the main means of controlling this disease and the amount of chlorothalonil allowed by the EPA foruse on golf courses has become increasingly restricted over the past decade. As I mentioned

earli er, r educing the allowable amount of fosetyl

- Al for use on turf would render this material ineffective against this disease. This would likely result in golf course superintendents and sports field managers using higher rate s of less effective product s for the control of anthracnose such as polyoxin

- D, f ludioxonil

, and f

luazinam . The same is true for Pythium diseases on turf, with many fungicide chemistries (e.g., the p henylamides ) no longer being effective or only effective at high label rates on many golf courses. Fosetyl

- Al is a very important rotational partner for the control of Pythium diseases (as well as anthracnose) on turf. Removing this chemistry would result in heavy reliance on other fungicide chemistries incre asing the potential for resistance.

With its systemic movement in turf, fosetyl

- Al is one of the only materials that can be sprayed on the foliage of turf to control Pythium root diseases. Although other phosphonate materials (e.g., the phosphites) are a lso be translocated to the roots, many are not registered as fungicides and thus would likely be used illegally in place of fosetyl

- Al i f it were to be removed from the marketplace. Moreover, in my efficacy studies over the past 20 years

, fosetyl

- Al + th e proprietary pigment in Chipco Signature has consistently been more effective than the phosphites for the control of anthracnose and often for the control of Pythium blight and root rot.

In closing, I would strongly recommend against reducing the allowa ble amount of fosetyl

Al on turf , since doing so would essentially remove it from the list of efficacious products available to the turfgrass industry. If I can provide any additional informati on, please feel free to give me a call (908) 227

- 1190

. Sincerely,

Bruce B. Clarke, Chairman Dept. of Plant Biology and Pathology Director, Center for Turfgrass Science Professor of Turfgrass Pathology Ralph Geiger Endowed Chair