First report of Erysiphe carpinicola s.l. (perfect state) in Poland

Carpinus betulus (hornbeam) is a native tree in Poland, often found in natural forest communities. It is also planted in parks and gardens, often as hedgerows. In Poland two species of powdery mildews (Erysiphales) have been previously recorded on this host plant: Phyllactinia guttata (Sałata, 1985) and Oidium carpini (Piątek, 2004). In November 2005, in Lublin (eastern Poland), chasmothecia of Erysiphe carpinicola s.l. (formerly Uncinula geniculata var. carpinicola) were collected from leaves of hornbeam. White mycelium was present on both leaf surfaces. Appressoria were lobed, occurring in opposite pairs or solitary. Conidiophores were erect with straight foot-cells (26-) 44–70 µm long. Conidia were solitary, cylindric or ellipsoid: (28-) 30–44 (−54) × (10-) 12–16 (-19) µm. Ascomata were numerous, on both sides of leaves either scattered or gregarious. Mature ascomata measured (80-) 86–110 µm in diameter. Appendages were equatorial, 2–3 times longer than the chasmothecium diameter, 16–24 per chasmocarp, circinate at the end. Asci 4–6 were shortly stalked or sessile: 46–48 × 24–34 µm, each containing 4–5 ellipsoid or ovoid (14-)16–20 × 10–13(-14) µm ascospores. The specimen has been deposited in the herbarium of the Botany and Mycology Department in Lublin (LBL M-8589). In Europe this species has previously been recorded in Hungary (Vajna, 2006) and the Ukraine (Minter et al., 2004). This is the first recorded occurrence in Poland.