WOOD DECAY, LIGNICOLOUS FUNGI, AND DECLINE OF PEACH-TREES IN SOUTH-CAROLINA

In the fall of 1990, a survey of lignicolous fungi and wood decay was conducted in 24 peach (Prunus persica) orchards in the Coastal, Ridge, and Piedmont regions (eight orchards per region) of South Carolina. A total of 2,400 trees, averaging 12.5 yr old, were evaluated for decay fungi; and 480 trees were evaluated for incidence, severity, and type of decay. Thirty-nine species in 30 genera were collected; 18 are new reports on peach in South Carolina, while 16 species are new reports on peach in the United States. Including the fungi in this study, the total number of wood rotting fungi reported on peach or nectarine in the United States and Canada is 67. White rot fungi were most commonly collected and included species in the following genera: Armillaria, Ganoderma, Laeticorticium, Oxyporus, Schizophyllum, Schizopora, Stereum, Trametes, and Trichaptum. Species of brown rot fungi collected were Antrodia albida, Fomitopsis meliae, F. nivosa, F. palustris, and Gloeophyllum mexicanum. The incidence of trees with decay was generally high, with orchard averages ranging from 20 to 100%. Incidences of decay were 63.7, 80.6, and 84.3% in the Ridge, Piedmont, and Coastal regions, respectively. Disease-severity ratings indicated that trees were affected mostly by decays of scaffold branches that were associated with improper stub-cut, pruning wounds. Based on tree age and health, wood decay is recognized as a distinct disease and is associated with declining peach trees in commercial production in South Carolina.