Some aspects of biology and host range of <i>Biscogniauxia</i> <i>mediterranea</i>, one of the causal agent of oak charcoal disease

Abstract

Field surveys in Zagros forests located in western Iran were done to study some aspects of biology and host range of <em>Biscogniauxia mediterranea</em> during 2014-2016<em>.</em> The ability of its conidia and ascospores to cause the disease was evaluated under greenhouse condition. Ascospore viability and development of anamorph and teleomorph were surveyed under different conditions. The pathogen host range was determined by field observations, laboratory and greenhouse tests. Results showed that ascospores unlike conidia produced colony and caused disease by inoculation into the lesion in <em>Quercus brantii</em> seedlings. Ascospore germination was decreased as much as 17.3% under forest conditions after one year. Extent necrosis in the inner bark and wood tissues of inoculated adult <em>Q. brantii</em> trees was induced however no fungal stroma has appeared for three years. Monopartite black stroma lacking teleomorph was formed beneath the outer bark of inoculated excised branches on which conidia were produced. Teleomorph was formed only on one <em>Q. infectoria </em>excised branch under natural-like condition. Teleomorph and anamorph have not produced on inoculated <em>Q. brantii, Q. infectoria </em>and <em>Q. libani </em>seedlings for 34 months. In the forest, the sign of charcoal disease was seen only on <em>Q. brantii</em> and <em>Q. infectoria</em> trees that the latter is a new host for it. Necrosis appeared in the inner bark of inoculated excised branches of <em>Amygdalus</em> sp. <em>Acer monspessulanum, Cerasus microcarpa, Pistacia</em> sp. and <em>Rosa</em> sp. but not in <em>Crataegus</em> sp. and <em>Ulmus</em> sp. Pathogenicity of <em>B. mediterranea</em> was demonstrated for the first time on seedlings of <em>Q. infectoria </em>and <em>Q. libani.</em>