Abstract
In June to September 1995, a new powdery mildew was found on baby's breath (Gypsophila paniculata L.) in Hiroshima and Fukushima, Japan. A white, powdery mycelial colony appeared on the leaves and stems of the plants. Conidia were ellipsoid to cylindric, 31-54×14-22μm, forming singly on conidiophores. Lobed appressoria differentiated on the germ tubes from conidia. Cleistothecia were not found on diseased plants. On the basis of the morphology of conidial stage, the fungus was proposed to be an Oidium sp. of the Erysiphe polygoni type. “Powdery mildew of baby's breath” was proposed for the disease.
