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Disease Note.

First Report of Stem Cankers Caused by Cytospora Specie on Alnus incana in Oregon. G. M. Filip, Department of Forest Science, Oregon State University, Corvallis 97331. C. A. Parks, Pacific Northwest Research Station, USDA Forest Service, 1401 Gekeler Lane, La Grande, OR 97850. Plant Dis. 75:1186. Accepted for publication 11 July 1991. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/PD-75-1186B.

A geminivirus was widespread on cultivated tomato (Lycopersicon esculentum Miller) in west central and southwest Florida in the fall of 1989 (2), all of 1990, and the spring of 1991. Both field-collected adults of Bemisia tabaci (Genn.) from symptomatic tomato plants and laboratory-reared adults from a 2-yr-old colony on poinsettia confined 72 hr on symptomatic field plants transmitted the virus to healthy tomato seedlings in the greenhouse. Symptoms appeared on 70% of the seedlings in 2-3 wk. Colony whiteflies (20 per plant) transmitted the virus from the newly infected greenhouse tomato seedlings to healthy seedlings at the rate of 70% when given 72-hr acquisition and inoculation periods. Presence of gemini virus was confirmed by microscopic examination of symptomatic leaf tissues for characteristic nuclear inclusions (1). This is the first report of a whitefly-transmitted geminivirus on tomato in Florida.

References: (1) R. G. Christie et al. Phytopathology 76: 124, 1986. (2) G. W. Simone et al. Phytopathology 80: 1063, 1990.