Studies on pepper powdery mildew. 2. Conidiophore emergence and conidial formation on pepper leaf

Studies on pepper powdery mildew. 2. Conidiophore emergence and conidial formation on pepper leaf

1981

A:PS

The formation of conidiophores and conidia were observed under an optical and scanning electron microscope. Leveillula taurica is one of a few endophytic species of powdery mildew. From inoculation to the emergence of fungus through stomata, it takes 3 days in summer and 7 days in winter. However, it was found in our experiments that this fungus was not only endoparasitic, but that it also had a creeping habit on the surface of pepper plants to form conidiophores on superficial mycelia (8 percent). Conida were formed within 20 hours of conidiophore formation. Primary and secondary conidia differed markedly: primary conidia were boat-like in shape while secondary conidia were elliptical. The conidia were about 130x30 um in size, with thorn-like projections on the surface. Such projections were also recongnized on the surface of conidiophores, on which they were concentrated on about the upper two-thirds of the surface below the conidia. They gradually thinned out and none were foung on the conidiophore-base. This thorn-like projection on conidia and conidiophores is one of the features of L. taurica. Several kinds exophytic species, Sphaerotheca fuliginea, Erysiphe graminis, Cystotheca lanestris and Oidium euonymi-japonicae from the phenomena that conidia easily adhered to the abaxial surface of pepper leaves or a needle when they were gently attached, and in rare cases printed their traces on a slide galss when they were stirrd with a needle after being attached to it, the surface of the conidia may possess some adhesive substance. [AS]

v.47(2):143-150, PHYTOPATHOLOGICAL SOCIETY OF JAPAN, ANNALS

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