Characterization of Cylindrodendrum, Dactylonectria and Ilyonectria isolates associated with loquat decline in Spain, with description of Cylindrodendrum alicantinum sp nov.

Thirty-one loquat orchards (Eriobotrya japonica 'Algerie') with plants exhibiting decline symptoms were surveyed between 2004 and 2007 in the province of Alicante, Spain. Twenty-eight representative isolates with Cylindrocarpon-like asexual morphs recovered from affected roots were included in this study, with the objective to characterize them by means of phenotypical characterization, DNA analysis and pathogenicity tests. Dactylonectria alcacerensis, D. torresensis and Ilyonectria robusta were identified based on morphological and cultural characteristics as well as DNA sequence data for part of histone H3, with D. torresensis the most frequent species. All of them are reported for the first time on loquat, and I. robusta is reported for the first time in Spain. In addition, one species is newly described, Cylindrodendrum alicantinum. Pathogenicity tests with representative isolates showed that these species were able to induce typical root rot disease symptoms, affecting plant development or even leading to plant death. This research demonstrates the association of species belonging to the genera Cylindrodendrum, Dactylonectria and Ilyonectria with root rot of loquat and loquat decline in the province of Alicante (eastern Spain). This information should be considered for the improvement of the current management strategies against these soil-borne pathogens when establishing new loquat plantations or introducing new susceptible fruit crops in the region.