pnut pnut Peanut Science 0095-3679 0095-3679 American Peanut Research and Education Society 10.3146/i0095-3679-8-1-3 Articles Effect of Cyhexatin (Plictran) on Growth, Conidial Germination And Sporulation of Cercospora arachidicola1 H. A. Melouk 2 Research Plant Pathologist, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Department of Plant Pathology, Oklahoma State University, Stillwater, OK 74078. Mention of a trademark, proprietary product or vendor does not constitute a grarantee or warranty of the product by the USDA or by Oklahoma State University, nor imply their approval to the exclusion of other products or vendors that may also be suitable

1Cooperative investigations of Agr. Res., Science and Ed. Admin., USDA and Oklahoma State University. Journal Article No. 3803, Oklahoma Agricultural Experiment Station, Oklahoma State University, Stillwater, OK 74078.

This is a report on the current status of research concerning use of a chemical that requires registration under the Federal Insecticide, Fungicide, and Rodenticide Act, as amended by the Federal Environmental Pesticide Control Act. Cyhexatin is not presently registered on peanuts with the Environmental Protection Agency. No recommendations for use of this chemical are implied in this report.

 1 1981 8 1 11 12 4 12 1980 American Peanut Research and Education Society 1981 American Peanut Research and Education Society Abstract

Growth of Cercospora arachidicola Hori, the causal agent of early leaf spot disease on peanuts, was completely inhibited on Czapek-Dox broth medium amended with the acaricide cyhexatin (Plictran) at ≤ 73.5 μg/ml; however, at 14.7 μg/ml traces of growth occurred after 6 weeks of incubation at 27±2C and continuous fluorescent light (800 lux). Aqueous preparations of cyhexation at ≤ 147.0 μg/ml completely inhibited the germination of conidia of C. arachidicola. At a concentration of cyhexatin ≤ 73.5 and 14.7 μg/ml, less than two percent of the conidia germinated as compared with more than 95 percent germination in distilled water. Misting of aqueous preparations of cyhexatin at ≤ 147.0 μg/ml on the adaxial or both surfaces of peanut leaflets with mature leafspot lesions was very effective in reducing the sporulating potential of C. arachidicola.

 Key Words Arachis hypogaea; , anti-sporulants; , chemical control; , tricyclohexyl hydroxystannane; , tricyclohexyltin hydroxide