A brief global review on the species of cucurbit powdery mildew fungi and new records in Taiwan

In spite of the economic importance of powdery mildew on cucurbits, literature and databases about the fungal species reveal different species numbers and names, often indicating only two species, with inconsistent host specificities for different members of Cucurbitaceae. Revision of the available literature indicates the presence of at least six species of powdery mildews on Cucurbitaceae with different focuses on hosts and geographic distribution. Golovinomyces orontii is recorded from Cucurbitaceae in Taiwan for the first time based on internal transcribed spacer sequences and the morphology of the anamorph found on wild plants of Coccinia grandis. In the literature; although, winter melon (Benincasa hispida) is considered resistant against Podosphaera xanthii, we confirmed a previously doubtful record on this host in Taiwan. Our new records of G. orontii in wild cucurbits and of P. xanthii for winter melon indicate a higher potential threat against cultivated cucurbits than previously estimated.