First Report of Sapwood Rot of Peach Caused by Schizophyllum commune in China

Peach,Prunus persica (L.) Batsch, is widely cultivated in gardens and plantations in northern China. During the summer of 2002, a severe sapwood rot of 5-year-old saplings was observed in a commercial nursery near Tieling, Liaoning Province, northeast China, 42°24′N, 123°55′E. More than 80% of saplings were infected and 35% were dead. Leaves were chlorotic or necrotic and dry, and wood discoloration and white sapwood rot were observed in cross sections of infected trees. Basidiocarps on the diseased trees were identified as Schizophyllum commune Fr.:Fr. (2); on potato dextrose agar (PDA), isolates obtained from decayed wood yielded colonies characteristic of S. commune as well (3). Basidiocarps had been initiated in early June and sometimes fruited over the entire length of the stem and some parts of major branches. Liaoning Province had an abnormally cold winter in 2001 and freeze injury may have predisposed the saplings to S. commune. In addition to P. persica, P. pseudocerasus Lindl. and P. salicina Lindl. were symptomatic. Pathogenicity was confirmed by inoculation of healthy saplings of peach in the greenhouse. Saplings were subjected to freezing for 1 week and 15 were inoculated with S. commune and five were inoculated with agar. Mycelial plugs, grown for 9 days on PDA, were the inoculum for stem wounds. The inoculated area was then covered by wet cotton and wrapped in Parafilm for 2 weeks. Symptoms developed on 14 of 15 inoculated saplings after 6 weeks. Symptoms progressed from chlorotic leaves to decayed bark and wood. After 10 weeks, 11 saplings were dead. The pathogen was reisolated from 13 of 14 symptomatic saplings, and fruiting bodies of S. commune developed on eight saplings. Control saplings remained symptomless. In China and the United States, S. commune is widely reported as a saprotroph or opportunistic pathogen of many woody angiosperms (4) and some gymnosperms (1). To our knowledge, this is the first report of S. commune causing sapwood rot of P. persica in China. References: (1) D. F. Farr et al. Fungal Databases, Systematic Botany and Mycology Laboratory. On-line publication. ARS, USDA, 2005. (2) J. P. Lindsey et al. Bibl. Mycol. 63:1, 1978. (3) M. K. Nobles. Can. J. Res. Sect. C Bot. Sci. 26:281, 1948. (4) F. L. Tai. Sylloge Fungorum Sinicorum. Science Press, Beijing, 1979.