Penetration and Infection Process of Phyllactinia corylea on Mulberry Leaf Causing Powdery Mildew — I. Asexual Stage

Surface morphology of conidia of Ph!,/laclillia cory/eo (Pers.) Karst.. its germination. penetration of hyphal bra nches and the infec tion process on mulberry leaf are described, under sca nning electron microscope. Surface or the clava te. hya line conidium is ornamented with evenly distribuled spine-like protrusions. The conidia germi nate 4 h after inoculati on. producing a single germ lu be moslly from a little behind the distal end of lhe conidium. The hyphae soon produce special branches. slomatopodia. which enler the leaf lhrough SLOmata. The tomatopodia are produced singly or in pairs. and one or two stomatopodia enter in a stoma. The bra nched superficial hyphae forms a mycelial mass wilhin 72 h afler inoculation. The disease becomes apparent at conidial stage. The conid iophores were straigh t at ea rl y stages. but appea red spira lly coiled when the conidia were mature. which may aid for conidial detachment