Pathogenicity of Cladosporium halotolerans on some legumes

In 2018, a drastic Ascochyta blight epidemic on chickpea crops occurred in the Northwest of Iran. A survey was conducted in the region to identify races of Ascochyta rabiei and estimate the yield loss. Infected plant samples were taken from an infected field in Pasvah region and transferred to the lab at Dryland Agricultural Research Institute (DARI), Maragheh. In addition to A. rabiei, a Cladosporium-like taxa is also isolated from plants showing disease symptoms. Based on morphological characteristics and DNA sequence comparisons, isolates of this fungus were identified as Cladosporium halotolerans. Pathogenicity tests and Koch’s postulates were verified and fulfilled on chickpeas under controlled conditions. The disease symptoms developed on the host plant after 5 days after inoculation (dai) under controlled conditions included appearing yellow-brownish leaflets on the branches that latterly turned to wilt and were covered with gray-black mold. Histological studies also confirmed the pathogenicity of this fungus on chickpeas. Host range investigations were carried out on the further six species belonging to the Fabaceae, including garden pea, lentil, garden vetch, narbon vetch, bitter vetch, and grass pea. Results showed that this pathogen can produce the same disease symptoms on all inoculated, as well. This study represents the first attempt to pathogenicity of C. halotolerans on legumes in the world.