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Etiology

Microorganisms Isolated From Wounds Inflicted on Red Maple, Paper Birch, American Beech, and Red Oak in Winter, Summer, and Autumn. Alex L. Shigo, Chief Plant Pathologist, U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station, Durham, New Hampshire 03824; Phytopathology 66:559-563. Accepted for publication 12 November 1975. DOI: 10.1094/Phyto-66-559.

Microorganisms were isolated from wood adjacent to 459 wounds inflicted during winter, summer, and autumn on 42 trees: 27 Acer rubrum, five Betula papyrifera, five Fagus grandifolia, and five Quercus rubra. The fungi isolated most frequently from 1- to 4-week-old winter wounds were Cytospora spp.; from the same age summer wounds, Ceratocystis spp.; and from the same age autumn wounds, Phialophora spp. Bacteria were isolated frequently from 1- to 4-week-old summer and autumn wounds, but seldom from 1- to 4-week-old winter wounds. Bacteria and nonhymenomycetous fungi were the only microorganisms isolated from recently inflicted wounds. Hymenomycetes were isolated from a few 7-, 8-, 9-, and 10-week-old summer wounds, but not from winter wounds until after 5 months. These data indicate that the first microorganisms to invade wounds inflicted at different seasons in the northeastern USA are different and that the time before Hymenomycetes are isolated also differs for wounds inflicted at different times of the year.