Initiation and development of cankers caused by virulent and cytoplasmic hypovirulent isolates of the chestnut blight fungus

Publisher Website
Google Scholar
Abstract
Stems of American chestnut were inoculated with a virulent (V) isolate of Endothia parasitica alone or containing different agents for cytoplasmic hypovirulence (CH). The V isolate (EP 155) initiated cankers in cork borer wounds 0,1,2,4,7,14,21, or 28 days old. Infection of this V isolate with CH agents Hl2 (EP 780), HMU (EP 868) or HT2 (EP 905), restricted canker development to wounds 0–7 days old, Odays old, or to none of the wounds 0–28 days old, respectively. Inoculation of several wound types with V or CH conidia collected from cankers or agar cultures resulted in few cankers. Measurement of electrical resistance (ER) of bark at different heights along chestnut stems indicated that ER was lowest at stem bases. Cankers initiated artificially at stem bases with mycelium from V or CH isolates were smaller and enlarged more slowly than did cankers initiated at more elevated stem positions. Areas of cankers initiated in detached chestnut stems in which moisture contents were regulated were inversely related to moisture content and directly related to ER of chestnut bark.

This publication has 0 references indexed in Scilit: