Phoma negriana, a new invasive pathogen for Moghan's vineyards in Iran

Abstract

During disease diagnosing studies in Moghan area, northern west of Iran, symptoms of black rot and necrosis were observed for the first time on Vitis venifera. Incidence was first noticed on leaves and stems. Symptoms occurred as small brown spots on leaves and stems, and developed as blackishbrown necrosis/canker so that the black pycnidia extended at the central parts of them. On the fruit, symptoms appeared as mummification of berries that were visible in the infested vineyards until winter time. The loss due to the disease along with downy mildew was remarkable during the studied years and can lead to substantial yield losses in Moghan climate condition. In order to identify the causal agent, the pathogen was isolated from infected leaves and stems. Also pathogenesity test was carried out by inoculating the causal agent to grapevine cuttings. According to culture, pycnidia and conidia characteristics described by Boerema et al. (2004), the results pointed toward Phoma negriana Thum as
the causative organism.