Potential host range of Stilbocrea banihashemiana and susceptibility of economically important trees to this emergent fungal canker-causing pathogen

Abstract

Stilbocrea banihashemiana is a recently described species of ascomycete fungi (Bionectriaceae) that causes canker and dieback diseases on fig and barberry, and dieback on loquat trees. Previous studies suggested this pathogen might affect other trees including economically important fruit crops, such as almonds, apples, and olives. This study assessed the susceptibility of 40 tree species belonging to 20 plant families, including fruit-bearing, ornamental, and edible landscape plants, to S. banihashemiana. The assessment was conducted by wound-inoculating detached shoots and one-year-old saplings with the pathogen. Based on five parameters of induced lesions, we clustered the inoculated tree species using the principal component analysis approach. The results of the approach revealed four distinct groups of tree species based on their susceptibility traits. Almond, apricot, eucalyptus, poplar, and red mulberry clustered in one group as susceptible hosts. The majority of the species examined, which included both tropical and temperate trees, were categorized as moderately susceptible. Platanus and sweet orange were identified as non-host-resistant species, while Arizona cypress, garden privet, and olive were classified as low susceptible. Moreover, our findings suggest a correlation between temperature and the aggressiveness of S. banihashemiana. This study revealed that the emerging pathogen, S. banihashemiana, could have a broader host range than currently recognized. The accidental introduction of this pathogen through the global trade of live host plants may pose a significant threat to economically important trees in temperate and subtropical regions.