Silverleaf (<em>Chondrostereum purpureum</em>) Effects on Japanese Plum (<em>Prunus salicina</em>)

Abstract

Silverleaf is an important trunk disease of fruit crops, like Japanese plum. It is known that Chondrostereum purpureum produces wood discoloration, leaves silvering and tree decline, however, the information about the effects on fruit production is scarce. Therefore, the objectives of this study were to determine C. purpureum pathogenicity on Prunus salicina and effects on physiology, fruit yield and quality, in Chile, in 2019 and 2020. Wood samples from affected plum trees were collected in the Chilean plum productive area. Fungi were isolated plating wood sections from the necrosis margin on culture media. Isolates colonies morphological and molecular characteristics accorded to C. purpureum (98%). Representative isolates were inoculated on healthy plum plants and after 65-d incubation, wood necrotic lesions and silver leaves were visible. Fungi were reisolated, fulfilling Koch&amp;rsquo;s postulates. To determine Silverleaf effects, water potential, and fruit yield and quality were measured in healthy and Silverleaf diseased plum plants cv. &amp;lsquo;Angeleno&amp;rsquo;. Water potential was altered on diseased trees, and their yield was reduced in 51% (2019) and 41% (2020), compared to fruit from healthy plants. Moreover, cover-colour, equatorial-diameter and weight were reduced, and fruit were softer, failing to meet the criteria to be properly commercialized and exported to demanding markets.