Verticillium wilt in Ailanthus altissima trees in Austria
Ailanthus altissima (Simaroubaceae: EPPO List of Invasive Alien Plants) commonly known as tree of heaven is an invasive alien plant species in the EPPO region and native to North and Eastern China. A. altissima can invade a variety of habitats including managed and unmanaged grasslands, forests, riverbanks/canalsides, rail/roadsides, wastelands and urban areas. A. altissima establishes itself readily on artificially disturbed sites such as roadsides and ditches, particularly in the Mediterranean region, such as in Southern France. Young trees grow rapidly, outcompeting other plant species for light and space. Control of the tree is often expensive and where the species grows near water the use of chemicals is restricted. In 1997, dieback and mortality was observed in individuals in Austria and the cause was attributed to Verticillium spp. and other fungi causing bark canker. Between 2011 and 2016 extensive surveys were conducted in Eastern Austria where Verticillium spp. were reported as widespread in the A. altissima population. Verticillium dahliae was found at 56 of the sampled 77 sites and V. nonalfalfae was identified from 2 of the 77 sites. The authors suggest that the rare detection of V. nonalfalfae may be related to its narrow host range, compared to V. dahliae, and further studies are warranted to evaluate its potential as a biocontrol agent.
Sources
Maschek O, Halmschlager E (2017) Natural distribution of Verticillium wilt on invasive Ailanthus altissima in eastern Austria and its potential for biocontrol. Forest Pathology, DOI:10.1111/efp.12356.