Comparative morphological studies on tomato powdery mildew (Oidium neolycopersici)

Abstract

Fourteen isolates of tomato powdery mildew (Oidium neolycopersici) and one isolate of the following species: Podosphaera fusca (= Sphaerotheca fusca), Erysiphe orontii (cucumber powdery mildews), Erysiphe cichoracearum (lettuce powdery mildew) and Erysiphe aquilegiae var. ranunculi (Ranunculus lingua powdery mildew) were used for comparative morphological studies. Basic characteristics of the anamorphs, including outer conidial wall patterns, were compared using light and scanning electron microscopy (SEM). In main morphological features, O. neolycopersici was strongly differentiated from E. cichoracearum, E. orontii and P. fusca. However, based on morphological features (e.g. germination type; appressorium shape; morphology of conidiophores) O. neolycopersici was close to E. aquilegiae var. ranunculi (both belong to Oidium subgen. Pseudoidium) and it probably could be placed to Erysiphe sect. Erysiphe (= Erysiphe s. str.)