Ilyonectria palmarum sp. nov. causing dry basal stem rot of Arecaceae

During surveys conducted in 2010–2013, acomplete breakage or bending of the trunk and a dry basalstem rot were observed on containerised Brahea armata,B. edulis, Howea forsteriana and Trachycarpus princepsplants in different nurseries located in eastern Sicily(southern Italy). A cylindrocarpon-like species was consistentlyobtained from diseased palm tissues, whileknown pathogens of these hosts such as Ganoderma,Phytophthora and Thielaviopsis were not found associatedwith symptomatic tissues or isolated on standard orselective media. A total of 40 cylindrocarpon-like isolateswere collected and characterised based on morphologyand DNA phylogeny. Multigene analyses based on the β-tubulin, histone H3, translation elongation factor 1-α, andthe internal transcribed spacers (ITS1, 5.8S, ITS2) genesfacilitated the identification of a new species, describedhere as Ilyonectria palmarum. The pathogenicity ofone representative isolate collected from each palmspecies was tested on plants cultivated under nurseryconditions and in a growth chamber. All isolates werepathogenic to B. armata, B. edulis, H. forsteriana, andT. princeps and symptoms identical to that observed innurseries were reproduced. Dry basal stem rot andstem bending caused by Ilyonectria palmarum representsa potentially serious problem for nurseries cultivatingcontainerised palms.