Chemotherapy of Cherry Buckskin and Peach Yellow Leafroll Diseases: An Evaluation of Two Tetracycline Formulations and Methods of Application. R. F. Lee, Associate Professor, University of Florida, Institute of Food and Agricultural Sciences, Citrus Research and Education Center, 700 Experiment Station Road, Lake Alfred 33850. George Nyland, and S. K. Lowe. Professor, and Staff Research Associate, University of California, Department of Plant Pathology, Davis 95616. Plant Dis. 71:119-121. Accepted for publication 29 July 1986. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-0119.

Two formulations of tetracycline, N-pyrrolidinomethyl tetracycline and oxytetracycline hydrochloride, were tested for their efficacy by high-pressure or syringe injection on cherry trees affected with buckskin disease and by high-pressure, syringe injection or gravity bag infusion on peach trees affected with yellow leafroll (PYLR). The trees were treated in August 1983 and evaluated before harvest in 1984. The disease rating of cherry trees affected with buckskin disease was reduced from severe to mild by both antibiotic formulations when 4 g a.i. was injected per tree, providing economic control. When peach trees affected with PYLR were injected with 2 g a.i. of antibiotic per tree, the average disease rating of the trees was reduced from severe to moderate by high-pressure injection, syringe injection, and gravity bag infusion of both formulations. No significant differences in efficacy were found between the two tetracycline formulations or between the method of application in either cherry or peach. Three grams active ingredient of either formulation will provide economic control of PYLR disease in peach.