Phenolase and Pectic Enzyme Activity in the Chocolate Spot Disease of Beans

Abstract

THE chocolate spot disease of beans (Vicia faba L.) caused by Botrytis fabae Sard. is so named because an early result of infection by the fungus is a small brown lesion on leaf or stem. In the course of studying the factors controlling the development of these lesions, it was found that the latent phenolase of bean leaves could be activated by certain pectic substances and by a soluble cellulose derivative in a way similar to that described by Kenten¹ for anionic wetting agents. The result of phenolase action, with the naturally occurring leaf phenols as substrate, is an intense brown coloration.