Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . FUNGI AFFECTING THE ONION more or less. The Onion Mildew Peronospora schleideniana This disease appears upon the tops of onions as agrayish, moldlike, velvety coating, which is followed by ilting of the affected leaves (Fig. 65).Seed onions seem to be the most liableto injury, and crops grown on low, dampground, are more subject to attack thanthose in higher, drier situations. Thefungus has been known in Europe as aserious enemy, for many years, but hasonly
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . FUNGI AFFECTING THE ONION more or less. The Onion Mildew Peronospora schleideniana This disease appears upon the tops of onions as agrayish, moldlike, velvety coating, which is followed by ilting of the affected leaves (Fig. 65).Seed onions seem to be the most liableto injury, and crops grown on low, dampground, are more subject to attack thanthose in higher, drier situations. Thefungus has been known in Europe as aserious enemy, for many years, but hasonly been recognized in America forabout a decade. The threads of the fun-gus push about between the tissue cellsof the liost, destroying their contentsand. causing the collapse of the leaves. Certain branchesare sent out through the breathing pores of the leaf, onwhich the spores are developed, as shown in Fig. cpores are pointed-oval in shape, and have a faintpurplish tinge; they are easily detached, and wafted orwashed from plant to plant by wind or water. Underfavorable conditions they quickly germinate, enteringthe tissues through the breathing pores by means of a
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
