VIEW ARTICLE

Etiology

Verticillium Wilt of Yellow Poplar. A. L. Morehart, Associate professor of Plant Pathology, Plant Science Department, University of Delaware, Newark 19711; F. M. Donohue III(2), and G. L. Melchior(3). (2)(3)Graduate research assistants, respectively, Plant Science Department, University of Delaware, Newark 19711, (2)Present address: American Cyanamid Company, Agricultural Division, P.O. Box 400, Princeton, NJ 08540. Phytopathology 70:756-760. Accepted for publication 28 January 1980. Copyright 1980 The American Phytopathological Society. DOI: 10.1094/Phyto-70-756.

The pathogenicity of Verticillium dahliae and V. albo-atrum to yellow poplar was demonstrated. Five V. dahliae and two V. albo-atrum isolates from four host species were tested for pathogenicity to six hosts. The order of relative susceptibility of these hosts, from most to least, was eggplant, maple, tomato, yellow poplar, potato, and dahlia. Cultures from root and soil samples collected in a survey from 96 yellow poplar sites located in woodlots throughout Delaware indicated an incidence of Verticillium spp. of 14.6%. V. albo-atrum was isolated from the roots of asymptomatic mature yellow poplar trees and diseased yellow poplar seedlings; whereas, V. dahliae was isolated only from rhizospheres. Eleven isolates obtained from the survey all induced disease when inoculated into yellow poplar or Bonnie Best tomato seedlings.