Thomas Thomidis, Pomology Institute Naoussa (NAGREF), R. S. Naoussas 38, 59200, Imathia Greece; and
Themis J. Michailides, Department of Plant Pathology, University of California, Davis, Kearney Agriculture Center, Parlier 93648
Phomopsis sp., the imperfect stage of the genus Diaporthe, is an increasingly common fungal pathogen of peach (Prunus persica). This study is the first report of the occurrence of a shoot blight and canker disease of peach in Greece caused by the fungus Diaporthe eres. The pathogen caused distinct cankers with abundant gumming on shoots of peach and nectarine trees. The rate of development of D. eres in vitro was reduced as temperatures increased from 25 to 30°C or decreased from 25 to 15°C, and was totally inhibited at 35 and 10°C. Storage at 10°C of peach fruit inoculated with D. eres controlled the development of fruit rot. Pathogenicity tests showed that 27 peach and nectarine cultivars grown in Imathia Prefecture, Greece, were equally susceptible to D. eres. The fungicides thiophanate methyl, carbendazim, tebuconazole, iprodione, and the mixture of cyprodinil:fludioxonil were evaluated against the development of D. eres and the disease symptoms. Thiophanate methyl, carbendazim, and tebuconazole significantly inhibited the growth of D. eres whereas iprodione and the mixture of cyprodinil:fludioxonil were less effective in inhibiting mycelial growth and disease symptoms. The sensitivity of 24 isolates of D. eres to carbendazim, thiophanate methyl, and tebuconazole was also tested. The results showed that most of the isolates used were sensitive to these fungicides, with some isolates showing a level of insensitivity. In general, the disease caused by D. eres could be a threat for peach cultivation in Greece and its management should be investigated in the field.