The infection of rose and holly by the pathogenic fungus Pestalotiopsis guepinii.

摘要

Pestalotiopsis is a plant pathogenic fungus that causes leaf spot on various host plants. The lesions are small (about 1-1.5 cm in diameter), brown in color, and may result in premature defoliation of infected leaves. Pestalotiopsis guepinii has been isolated from Camellia sinensis, Laurus sassafras, Azalea, Erica, Hippocratea, Jatropha curcas, Pinus potula, Rhododendron and Terminalia bellerica. The fungus was isolated from rose (Rosa) and holly (Ilex) plants in the East Texas region and pure cultures were maintained on potato dextrose agar. Plants were artificially inoculated and conidial germination and penetration structures were observed using epifluorescence light microscopy and scanning electron microscopy. Penetration occurred via an appressorium. Intercellular fungal hyphae and host cell death were examined using Nomarski DIC light microscopy and transmission electron microscopy. Visible lesions were produced on rose but not on holly, although both hosts were colonized by hyphae. It is possible that latent infections may occur on holly without any obvious symptom expression until the plant becomes stressed.