Pathogenicity of Tubakia dryina. G. P. Munkvold, Former Research Associate, Department of Plant Pathology, University of Illinois, Urbana 61801. D. Neely, Plant Pathologist, Illinois Natural History Survey, and Professor, Department of Plant Pathology, University of Illinois, Urbana 61801. Plant Dis. 74:518-522. Accepted for publication 22 January 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0518.

Tubakia dryina has been associated with leaf spots of Quercus spp. and trees of other genera, but its pathogenicity has not been established. Isolates of T. dryina were collected from several Quercus hosts. Excised leaves of Q. alba, Q. rubra, Q. robur, Q. velutina, Q. imbricaria, Q. falcata var. pagodaefolia, Q. palustris, and chlorotic Q. palustris developed necroses when inoculated with isolates from Q. palustris or Q. imbricaria. Excised leaves of Acer saccharum, Nyssa sylvatica, Cercis canadensis, Carya ovata, Fraxinus americana, and Liquidambar stryaciflua did not develop necroses after inoculation. An isolate of T. dryina from Castanea pubinervis also caused necroses on excised oak leaves but not on other leaves. Branches of Q. rubra, Q. falcata var. pagodaefolia, Q. palustris, and chlorotic Q. palustris developed symptoms after inoculation in the field with an isolate from Q. palustris. Symptoms developed more rapidly with later inoculations and were more severe on chlorotic Q. palustris than on any other species.

Keyword(s): Actinopelte dryina.