First Report of Zonate Leaf Spot on Tomato, Caused by Cristulariella moricola, in New York. H. R. Dillard, New York State Agricultural Experiment Station, Geneva 14456. A. C. Cobb, Cornell University. New York State Agricultural Experiment Station, Geneva 14456; W. C. Carman and R. Brewer, Furman Foods Inc., Northumberland, PA 17857. Plant Dis. 79:319. Accepted for publication 19 January 1995. Copyright 1995 The American Phytopathological Society. DOI: 10.1094/PD-79-0319A.
Severe defoliation, fruit rot, and premature abscission of fruit occurred in two commercial fields (38 acres) of processing tomatoes (Lycopersicon esculentum Mill.) in Southport, NY, in the summer of 1994. Yield reduction due to zonate leaf spot was estimated at 50% in three tomato cultivars, Hypeel 696, Hypeel 2196, and Ohio 8245. The early symptoms consisted of light tan lesions with concentric rings on the leaflets that expanded and coalesced, resulting in rapid defoliation. Lesions also formed on the stems. Fruit infections appeared to result from expansion of lesions on the sepals and peduncle, and sclerotia were sometimes produced at the peduncular end. Infected fruit were water soaked and abscised readily. After periods of high humidity, pyramid-shaped conidia were formed on the older leaf lesions. Cristulariella moricola (Hino) Redhead (= C. pyramidalis Waterman & Marshall) was isolated from lesions on potato-dextrose agar and V8 juice agar. Inoculations of tomato plants grown in the greenhouse resulted in zonate leaf spots on leaflets similar to those in the field. Cristtilariella moricola was reisolated from artificially inoculated plants to complete Koch's postulates. Affected tomato fields were surrounded by woods containing box elder (Acer negundo L ) and black walnut (Juglans nigra L.) trees, which also showed symptoms of zonate leaf spot. Zonate leaf spot was severe on box elders and C. moricola was observed sporulating in young lesions. The pathogen was isolated from leaf spots on both box elder and black walnut. The infected trees are suspected of providing primary inoculum for infection of the tomatoes Disease gradients in the field suggested movement of the pathogen from the woods to the tomato fields. Cristulariella moricola has been reported previously on tomatoes in the U.S. in Arkansas, North Carolina, and West Virginia (1,2). This is the first report of C. moricola on tomatoes in New York.References: (1)J. C. Correll et nl. HortScience 27(6):628, 1992. (2) J. C. Trolingeret al. Plant Dis. Rep. 62:710, 1978.