Taphrina caerulescens

Taphrina caerulescens is a species of fungus in the family Taphrinaceae. It is a pathogenic Ascomycete fungus that causes oak leaf blister disease on various species of oak trees (Quercus spp.). The associated anamorph species is Lalaria coccinea, described in 1990. This disease causes lesions and blisters on Oak leaves. Effects of the disease are mostly cosmetic. Although not taxonomically defined, strains of T. caerulescens have been shown to be host specific with varying ¬ascus morphology between strains. There are differences in strains' abilities to metabolize various carbon and nitrogen compounds. This has been proposed as a method of taxonomically defining subspecies within T. caerulescens. Taphrina caerulescens is very closely related to Taphrina deformans, which causes peach leaf curl. These two pathogens have indistinguishable asci. However, T. deformans infects peach tree species while T. caerulescens infects Oak tree species only....read more on Wikipedia.