THE BIONOMICS OF THE PSEUDOV ALSELLA AND CORYNEUM CANKER OF CHINESE CHESTNUT

It has been demonstrated that this canker is caused by Pseudovalsella sp., whose clonal name is Coryneum kunzei Corde var. castaneae Sacc. & Roum, and which is hiterto found in Southwest of China only. The fungus is a weak parasite. This article describes the bionornics of the pseudovalsella sp. and Coryneum kunzei var. castaneae. The optimum temperature of the germination is 30℃ for eonidia, 35℃ for ascospore, and the best relative humidity is 65%. Sugar solution, the extract of the host's bark, pH 4 or pH 8, naturally diffused light and some ultraviolet light are beneficial to the germination of conidia and ascospore.