Identification of a suspected pathogen of Chinese pear (Pyrus bretshneideri Redh.) ‘Dangshansuli’ and fungicide screening

Abstract

SummaryWe have identified a pathogenic fungus that is responsible for fruit rot and leaf abscission in Chinese pear (Pyrus bretshneideri Rehd., cv. Dangshansuli). Six isolates of the fungus were obtained from diseased fruit and leaves and purified from single conidiospore cultures grown on potato-dextrose agar medium. The internal transcribed spacer (ITS) region of their ribosomal DNA was amplified, cloned, and sequenced. The results indicated that the rDNA-ITS sequences of all six isolates were identical to those of the anthracnose pathogens isolated from Taiwanese jujube (FJ233185) and Japanese pear (AB219012). This indicates that the disease observed in Chinese ‘Dangshangsuli’ pear was caused by the pathogen Colletotrichum gloeosporioides Penz, and/or its teleomorph, Glomerella cingulata. To determine an appropriate control strategy, 21 commercial fungicides were screened, and nine were found to be effective at inhibiting mycelial growth and the germination of conidia using controlled in vitro tests. Tests performed in 2009 and in 2010 revealed that three of these fungicides, Mancozeb, Bilu No. 2, and Triram, were efficient at controlling the disease. These results provide evidence for the most appropriate fungicides to use to control anthracnose disease in Chinese ‘Dangshansuli’ pear.