Calonectria species associated with diseased leaves and soils in southern China Eucalyptus plantations

Abstract Calonectria leaf blight (CLB) is one of the most important diseases Eucalyptus trees grown in plantations. This disease poses a serious threat to sustainability plantations southern China. To better understand causal agents CLB, we collected samples diseased leaves and soil from nine regions Guangdong Province where has become problem. A total 606 isolates were purified samples, with 399 207 originating soils, respectively. Phylogenetic analyses utilizing six gene resolved 303 C. kyotensis species complex an equal number reteaudii complex. These two complexes represented by ten known species, including aconidialis (12.0%), curvispora (0.3%), hongkongensis (24.8%), ilicicola (0.9%), (12.0%) complex, crousiana (1.0%), Guangdongensis pseudoreteaudii (40.7%), queenslandica (7.3%), (0.7%) . Pathogenicity tests showed that all capable causing on tested genotypes, albeit at varying degrees aggressiveness. Most (98.3%) leaves, indicating this are main CLB outbreak. In addition, significant (66.7%) could also cause leaves.