a contribution to the knowledge of taxonomy and identification of anamorphic genus oidium in guilan province, iran

many powdery mildew fungi occur as anamorphic state on different host plants in guilan province, iran. the species have usually been identified as oidium spp. in order to identify teleomorphic species using anamorphic characteristics and host range, several infected plant specimens were collected from around guilan province during 2004-2011. based upon  the  results of the study 25 species were collected and identified. the identified species are as follows: erysiphe cf. alphitoides on quercus sp., erysiphe australiana on lagerstroemia indica, erysiphe begoniicola on begonia multiflora, erysiphe betae on dysphania ambrosioides, erysiphe convolvuli on convolvolus sp., erysiphe euonymicola on euonymus japonicus, erysiphe heraclei on petroselinum hortense, erysiphe polygoni on polygonum persicaria, erysiphe platani on platanus orientalis, erysiphe quericicola on quercus sp., erysiphe sesbaniae on sesbania punicea, golovinomyces ambrosiae on zinnia sp. and dahlia sp., golovinomyces artemisiae on artemisia annua, golovinomyces biocellatus on mentha sp., golovinomyces montagnei on silybum marianum, golovinomyces depressus on arctium lappa, golovinomyces orontii on nicotiana tabacum, golovinomycescf. orontii on fraxinus sp., golovinomyces sonchicola on sonchus sp., podosphaera aphanis on agrimonia eupatoria, podosphaera euphorbiae-hirtae on pedilianthus sp., podosphaera fugax on geranium dissectum, podosphaera xanthiis.l. on dichrocephala sp., gerbera sp., physalis alkekengi and vigna unguiculata, podosphaera pannosa on rosa sp.,sawadaea bicornis on acer sp. among the identified species erysiphe australiana and podosphaera euphorbiae-hirtaeare recorded for the first time from iran.moreover, erysiphe alphitoides on castanea sativa, erysiphe betae on dysphania ambrosioides, erysiphe heraclei on petroselinum hortense,  podosphaera xanthiis. lat. on dichrocephala sp., gerbera sp., physalis alkekengi and vigna unguiculata, golovinomyces ambrosiae on zinnia sp.  and dahlia sp., erysiphe heraclei on petroselinum hortense, golovinomyces cf. orontii on fraxinus sp.are newly reported on these host plants from iran. in addition, golovinomyces montagnei, erysiphe begoniicola and erysiphe euonymicola are accepted as correct nomenclature for causal agents of powdery mildew on silybum marianum, begonia and euonymus respectively.