pnut pnut Peanut Science 0095-3679 0095-3679 American Peanut Research and Education Society 10.3146/i0095-3679-5-1-4 Articles Determination of Leaf Necrosis Caused by Cercospora arachidicola Hori in Peanut as Measured by Loss in Total Chlorophyll1 H. A. Melouk 2 Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Department of Plant Pathology, Oklahoma State University, Stillwater, OK 74074

1Cooperative investigations of Agric. Res. Serv., USDA, and Oklahoma State University, Journal Article No. 3378, Oklahoma Agricultural Experiment Station, Oklahoma State University, Stillwater, OK 74074.

3Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the USDA or by Oklahoma State University, nor imply their approval to the exclusion of other products that may also by suitable.

 1 1978 5 1 17 18 American Peanut Research and Education Society 1978 American Peanut Research and Education Society Abstract

Percent leaf necrosis can be used to assess severity of early leafspot caused by Cercospora arachidicola Hori on peanut (Arachis hypogaea L.). Measurements of leaf necrosis (%), as determined by area, and the corresponding loss (%) in total chlorophyll content were made. Correlations were calculated using linear regression, and logarithmic curve fit analyses. High positive correlation values were obtained between leaf necrosis and loss in total chlorophyll. Therefore, this method is suggested for a reasonably accurate and fast assessment of leaf necrosis of peanut caused by C. arachidicola.

 Key Words Leafspot; , disease assessment; , insoluble polyvinylpyrrolidone; , polyphenols