Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . inside the outer cuticleof the host-plant, among the cells of leaf, stem or fruit,sending out its fruiting branches when it has completedits growth. But with the class of so-called powderymildews, to which the present species belongs, the my-celium is external, developing on the outside of thehost-plant. The mycelium consists of slender white 94 FUNGI AND FUNGICIDES threads which run oyer the surface of the leaf, andobtain nourishment bj sending down into t
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . inside the outer cuticleof the host-plant, among the cells of leaf, stem or fruit,sending out its fruiting branches when it has completedits growth. But with the class of so-called powderymildews, to which the present species belongs, the my-celium is external, developing on the outside of thehost-plant. The mycelium consists of slender white 94 FUNGI AND FUNGICIDES threads which run oyer the surface of the leaf, andobtain nourishment bj sending down into the cells shortbranches, often called suckers. During the summerthese threads also send upward in the air certain otherbranches, which gradually divide into a number ofparts, as shown in a, Fig. 46, and thus produce thesummer spores, or conidia. These summer spores arevery light, and are blown about by the wind; when onefalls upon a damp gooseberry leaf it germinates by send-ing out a slender tube, from which the mildew startsanew. As the summer spores are unable to survive thewinter, the fui^gus produces, especially late in the sea-. no. 46. SPORES OF GOOSEBEERY MILDEW. MAGNIFIED. son, another kind of spures, the so-called winter are much more complicated in structure than theothers. As seen under the microscope, they consistexternally of a small round case, from wiiich projectabout a dozen short delicate appendages, like those rep-resented in h, Fig. 46. This is the outer spore case(called by botanists the perWiecium). If it be crushedit will break open on one side, and there will be pushedout a flattened oval body—the inner spore case, or ascus—within which may be seen eight small bodies, whichare the spores [h). By means of these the fungus sur-yiyes the winter. THE GOOSEBERRY MILDEW 95 Treatment.—Spray with a solution of potassiumsulpliide (liver of sulphur) at the rate of one-half ounceto one gallon of water. Begin as soon as the leavescommence unfolding
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
