Canning peach decline in Western Australia. I. Association between trunk cankers, trunk pruning wounds and crotch angles of scaffold limbs

Abstract

Decline of South African canning peach varieties, particularly commercial plantings of Keimoes, has occurred in Western Australia. From orchard observations and laboratory investigations, it is suggested that tree death follows on canker formation on the trunk. The cankers extend from areas of compressed dead bark between scaffold limbs and from large uncallused pruning wounds in the crotch and on the trunk. Wood-rotting fungi are considered to gain entry through the dead bark and uncallused wounds. Analysis of the data shows a highly significant relationship between many cankers and narrow crotch angles. No correlation has been established between the extent and severity of trunk pitting and the development of cankers.