First Report of Branch Canker and Dieback Caused by Cryphonectria naterciae on Quercus suber in Algeria

Over the last few decades, severe and widespread tree decline and mortality events have been observed in all the main growing cork oak (Quercus suber L.) forests in Algeria. In winter 2016, during a study on the fungal pathogens involved in the aetiology of cork oak decline, Diplodia corticola was found to be the main causal agent of branch canker and dieback. However, in addition to D. corticola, isolations from five branches showing exudation, sunken canker and dieback symptoms out of 29 trees investigated in the forest of M'sila (35°37'23''N - 0°53'00''O) yielded on potato dextrose agar (PDA) at 25°C orange to red fungal colonies, with a felty and uniform mycelium. Pycnidia were produced within 4 weeks in the centre of colony maintained on the laboratory bench at room temperature under natural daylight. The hyaline, cylindrical to ellipsoid and aseptate conidia were exuded in a yellow to orange gelatinous matrix and measured 2.7-5.6 × 0.9-2.1 μm (n = 50). All morphological characters corresponded to th..