Report of Boxwood blight extension to Golestan province forests (short report)

Boxwood)Buxus sempervirens subsp. hyrcana) is one of the main forest evergreen plant species through the Caspian Sea provinces. Boxwood is endemic to Iran and it has particular importance among the forest reserves in the world. Boxwood blight disease was reported, from the forests of Mazandaran and Guilan province in 2013 (2, 3). Calonectria pseudonaviculata, the causal agent of buxus blight can complete its life cycle within one week under its favorite temperature and humidity (1). Development of the disease is as fast as that the boxwood blight symptoms were observed broadly in Guilan and Mazandaran provinces. To monitor the epidemiology of the disease, the infected leaves and twigs were collected from boxwood trees in Bandargaz area, located in Golestan province. The infected plant tissues were surface sterilized with hypochlorite sodium (%5) and cultured on PDA (potato dextrose agar) medium to isolate the causal agent. Fungal isolates were purified using hyphal type method on water agar medium (1.5%). For spore production, the colonies were grown on PCA (potato carrot agar) and incubated under near- ultraviolet light at 25°C. The colony color on PDA was brown with pale hale. No mycellial growth was observed at 30°C which had been reported (1). Conidia were produced frequently after 15 days on PCA medium. Conidia were cylindrical, rounded at both ends, 1-septate, 48- 68 (47.3) ×4- 6 (4.8) µm. Stipe was long (90-14 µm), hyaline, the extension terminating in a broadly ellipsoid papillate vesicle, and with the widest part above the middle. This is the first report of outbreak boxwood blight disease throughout all of Hyrcanian forests located in Iran.