Mycotoxin Producing Fusarium Species – the Cause of Primary Stem Canker of Deciduous Forest Plants

Abstract

Fusarium species are spread worldwide and causing damages at different stages of tree development as well as are involved in many complex diseases of forest ecosystems. Most impact was assessed in forest nurseries with seedling diseases like root and hypocotyls rot and wilt. Moreover, afforestations and natural stands of young forest broadleaved trees were affected by a range of species with symptoms of foliage withering and dieback of branches as well as bark necrosis and canker. Because those alarming symptoms apeared more widespread in the last decade, Fusarium strains were isolated from affected young trees of black locust, birch, alder, and aspen from nurseries, afforestations and from natural stands in Germany. The isolates were classified in F. avenaceum, F. tricinctum, F. sporotrichioides, and F. sambucinum by conidia morphology and ITS sequencing of rDNA. Fifteen isolates were examined regarding their pathogenicity on six broadleaved tree species with artificial inoculation under glasshouse conditions. Furthermore, the mycotoxic properties of these strains were investigated from cell extracts produced in six different culture media by means of on-line couplings LC-PDA-Q-TOF-ESI-MS as well as LC-UV-NMR, and MALDI-TOF-MS.