Infection, Disease Development, and Axenic Culture of Entyloma compositarum, the Cause of Hamakua Pamakani Blight in Hawaii. E. E. Trujillo, Professor, Department of Plant Pathology, University of Hawaii, Honolulu 96822. M. Aragaki, and R. A. Shoemaker. Professor, Department of Plant Pathology, University of Hawaii, Honolulu 96822, and Head, Mycology Section, Biosystematics Research Institute, Wm. Saunders Bldg., C. E. F., Ottawa, Ontario, Canada K1A 0C6. Plant Dis. 72:355-357. Accepted for publication 4 November 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0355.

A Hamakua pamakani pathogen introduced from Jamaica in 1974 on Ageratina riparia leaves was isolated and pure cultures were grown on yeast morphology agar. Inoculations of axenically grown A. riparia seedlings resulted in typical leaf spots and abundant pathogen sporulation after 13 days of incubation at 18 C. There was no significant difference in numbers of spots produced on leaves inoculated through abaxial or adaxial surfaces. Germ tube penetration occurred between epidermal cells by dissolution of the middle lamella. This fungus is tentatively placed in the genus Entyloma, based on the two distinct types of conidia produced: short, broadly falcate conidia (15–20 × 3–3.5 ?m) and long, slender, arcuate conidia (30–40 × 1.5–2.5 ?m), characteristic of E. compositarum.