Journal of Plant Pathology Archive

Abstract:

Colletotrichum acutatum J.H. Simmonds is the causal agent of anthracnose on a wide range of hosts including woody and herbaceous crops, ornamentals, and conifers. Recently, infections caused by several Colletotrichum species (mainly C. acutatum, C. gloeosporioides, and C. capsici) have caused serious problems to hot pepper production in tropical and subtropical regions (Liao et al., 2012). In October 2013, during a survey in chili pepper cultivations of central Italy, fruits of Capsicum annuum were collected, showing circular sunken lesion with concentric rings of acervuli that produced pink to orange conidial masses. Fragments of symptomatic tissues cut from the margin of fruit lesions were placed on potato dextrose agar (PDA) amended with streptomycin and ampicillin (100 ppm each). Fungal colonies were identified as Colletotrichum acutatum on the basis of morphological characters, such as size and shape of conidia, colony color and growth rate. DNA of one monosporic isolate (CRA- PAV ER1856) was extracted and amplified with primers specific for the internal transcribed spacer (ITS) region. Homology search of related sequences present in GenBank showed 99% identity with the sequence of isolate SPu2-1 of C. acutatum which was deposited in the European Nucleotide Archive with the accession No. HG972966. Pathogenicity tests on pepper fruits were successful, thus Koch’s postulates were fulfilled. In Italy, C. acutatum causes damages to strawberries (de Clauser et al., 1990) and other crops, but it has never been found in hot pepper. Colletotrichum species are generally seed-borne, so infected seedlings and seeds may be a way for their introduction in new cropping areas. This pathogen represents a serious threat for pepper cultivation in hot and wet zones of our country.