The Zagros forests distributed in 11 provinces of Iran that has a total area of 6 million hectares, accounting for 40 percent of Iran's forests. Lorestan province has the second largest forest area “in terms of the area of forest habitats” in zagros. Lorestan With a total area of 28,000 km2, has 1230000 hectares of forest, equivalent to 44 percent of the province's area. Thesee forests are in the three climates in this province include “the mountainous cold zone, the temperate central region and the warm southern region”. This research was carried out in forest areas of Lorestan Province in order to identify the Erysiphaceae fungi as pathogens in these trees and shrubs. Infected trees and shrubs of Acer monspessulanum L., Daphne mucronata Royle, Salix alba L., Crataegus azarolus L., Quercus infectoria Oliv. subsp. Boisieri (Reut.) O. Schwarz, were collected. Then, identification of plant hosts, and identification of disease-causing fungi were performed. Among identified samples, Phyllactinia gutata (Wallr.) Lév.was identified on S. alba L. and C. azarolus L., that is the first record of this fungus on C. azarolus L. and the second record of this fungus from the world on S. alba L.. Also, the Leveillula taurica (Lév.) G. Arnaud on D. mucronata Royle is the second recorded for the world on this species. And Erysiphe alphitoides (Griffon & Maubl.) U. Braun & S. Takam on Q. infectoria Oliv. subsp. Boisieri (Reut.) O. Schwarz is the first record on this sub-species and the second record on this species from the world. And Sawadaea tulasnei (Fuckel) Homma on A. monspessulanum L.were identified as the second record of these fungi on this plant.