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The marigold (Calendula officinalis) is an herbaceous plant used by its beautiful yellow or orange flowers, in bordures, gardening and as cut flower. It is largely diffuse in the world, not only for the beauty of his flowers or his use in cosmetic, but for being resistant, of easy cultivation and for it low demanding in environmental conditions. In Mendoza it is very used as ornamental plant and every year is affected by a disease called powdery mildew. In Argentina there are mentioned as etiological agents of the disease different species of the generous Erysiphe, and Oidium erysiphoides. Nevertheless the teleomorphic form wasn't described until 1991 in Corrientes and Córdoba. There, it was reported as Sphaerotheca fusca. In 2004 in Mendoza, it was observed over marigold cultures a severe powdery mildew attack. Studying the problem, over the typical powder of the disease, the presence of black bodies was observed. This motivated to determine the etiology of the disease in Mendoza. Several samples of marigold plants affected were taken at different places. At the laboratory, morphological and morphometric studies permitted the identification of Podosphaera fusca (=Sphaerotheca fusca) as causal agent of the powdery mildew of the marigold in Mendoza. [ABSTRACT FROM AUTHOR]

Leveillula taurica (Lév.) Salm. is a pathogenic fungus, at the moment, in expansion in Argentina and particularly in Mendoza. Physalis viscosa (groundcherry) grows spontaneously in several cultures and in its surroundings in Argentina. The finding of L. taurica on camambú a wide spread specie in our country has motivated the present study. The symptoms were characterized by the presence of yellow cuneiform patches in the adaxial face of the leaves corresponding with a white plush on the other leave face. Etiological studies based on the histopa-thology of the diseased tissues and fungal morphology have confirmed the presence of Leveillula taurica (Lév.) Salm on it anamorphic face of Oidiopsis taurica Sal. [= Oidiopsis sicula (Scal)]. Since it was found for the first time in 1996 in Tupungato, the fungus has been spreading itself everywhere in Mendoza. The pathogen attacks camambú from Decem-ber to May. This lengthy attack period could represent and important source of inoculum for susceptible cultures. This paper is the first report of L. taurica on Physalis viscosa not only in Argentina but worldwide. [ABSTRACT FROM AUTHOR]