قارچ شناسی ایران
سال:1393 | دوره:1 | شماره:2 |تعداد مقالات:9

The powdery mildews belong to Ascomycota (Erysiphales) and are easily recognized by their conspicuous epiphytic mycelium. Anamorph state of most teleomorphic genera with exclusively external mycelium belong to the genus Oidium. Oidium states show a great deal of variation in morphology. Conidia are produced either in chains (Euoidium-type of the genus Oidium) or solitarily (Pseudoidium-type of the genus Oidium) which are hyaline, one-celled, uninucleate, vacuolate and thin-walled (Braun 1987). The length/width ratio and shape of conidia and foot-cells are usable for taxonomic purposes. The conidia of most Oidium species vary from cylindric, ellipsoid, ovoid to doliform and their surface is usually smooth. Khodaparast et al. (2000, 2001) and Pirnia et al. (2005–2007) have reported new species of powdery mildews in Iran.

The genus Geosmithia (Ascomycota: Hypocreales) belongs to mitosporic filamentous fungi with a worldwide distribution (Kolařík et al. 2011). This genus is characterized by penicillium-like conidio- phores with roughened walls, cylindrical phialides and smooth ellipsoidal to cylindrical conidia, forming long persistent chains (Kolařík & Kirkendall 2010; Sohn et al. 2013). Geosmithia species are found in soil, plant debris and wood and can act as true endophytes of healthy trees. Most species are known as exclusive associates of many insects invading phloem or sapwood of various plants (Kolařík et al. 2007; Kolařík & Kirkendall 2010; Moubasher & Soliman 2011).