Needle disease on English yew caused by the parasitic fungus Cryptocline taxicola (All.) Petr. noticed in Nitra town

Abstract

This study reports the occurrence of the fungus Cryptocline taxicola (All.) Petr. on needles of Taxus baccata L. Symptoms of fungal infection, irregular necrotic spots and lesions, followed by turning brown of infected needles and whole shoots, were observed on Taxus baccata var. fastigiata (Lindl.) Loudon and Taxus baccata var. fastigiata Robusta in private gardens of the town of Nitra. Some important characteristics and distinctive morphological features were described. Black, subcircular fruiting bodies (acervuli) were observed on the upper, but more massed on the lower side of necrotic needles. Conidia were ellipsoidal to ovoid, smooth-walled, brownish to hyaline, nonseptate, grainy inside, rarely with two oil drops, average size 5-15 x 4-5 µm. The fungus formed on PDA aerial, pale brown to greyish colonies with olive-brown shade and hyaline, branched, septate mycelium. Average growth rate of mycelium in culture reached 3.02 mm day-1. Experimental spraying with fungicide Dithane M45 showed to be effective. Because the English yew is affected by only a few serious fungal diseases, so the isolation and identification of C. taxicola - a fungal pathogen with sporadical incidence causing damage to needles of this woody plant was relatively uncommon. From this aspect the fungus Cryptocline taxicola seems to be important pathogen on needles of the English yew in Europa, including Slovakia.