Project reference: 1998-03
Sphaeropsis sapinea (Diplodia pinea) - A Review
A substantial body of work on the Sphaeropsis sapinea (Diplodia pinea) diseases of Pinus radiata in New Zealand was carried out over a period of 15 years (1972 - 1987) by Dr S Chou based at the Forest Research Institute. The experimental programme covered whorl canker, crown wilt and primary shoot infection. Results from the trials led to recommendations for minimising infection of pruned stubs and to an understanding of the circumstances and conditions under which the less common crown wilt and shoot infection occur, thereby allowing identification of sites where these diseases might be significant. Field observations of apparent variation in susceptibility to shoot infection were followed by glasshouse testing of the progeny of resistant trees and a programme investigating the relationship of levels of certain monoterpenes in shoots and the absence of dieback. A series of publications, and a number of unpublished FRI reports cover this work.
The fungus has also been blamed, in the absence of any evidence but undoubtedly because of its ubiquitous presence, for conelet abortion in seed orchards, and for resin bleeding on stems of mid-rotation trees in the Bay of Plenty.
A review of S. sapinea in New Zealand, bringing together in one paper the accumulated published and unpublished knowledge, is proposed. Work carried out on S. sapinea in other plantation-pine growing countries will also be reviewed and areas for future experimental and developmental work identified.
Although S. sapinea is the most frequent cause of whorl canker of P. radiata throughout New Zealand (Forest Health Database, FRI), there are several other fungi which are capable of infecting pruned stubs and causing degrade and/or dieback or mortality. As, at present, practical management of the disease depends on knowledge of the epidemiology of the invading fungus a review of records of non-Sphaeropsis infections is proposed as a further step. Available information on geographical distribution, and on the epidemiology of the recorded infections will be collated.