Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . pring, some-times longer—they ger-minate by sending outa tube (b), which soondevelops a number ofsecondary spores, or spo ?ridia (Fig. 68 a;). Thesesporidia themselves havethe power of germinat-ing, sending out a shorttube (c), which entersthe young plant justinfection apparentlyoccurs before the plant has appeared above ground; andwhile, as just indicated, it 2:)robably is usually due to thegerminating sporidia, it is also probable that it is some-times di
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . pring, some-times longer—they ger-minate by sending outa tube (b), which soondevelops a number ofsecondary spores, or spo ?ridia (Fig. 68 a;). Thesesporidia themselves havethe power of germinat-ing, sending out a shorttube (c), which entersthe young plant justinfection apparentlyoccurs before the plant has appeared above ground; andwhile, as just indicated, it 2:)robably is usually due to thegerminating sporidia, it is also probable that it is some-times directly due to spores which do not develop spo-ridia. After the fungus has once gained access to theyoung onion plant, the development of mycelium begins,and continues until a new crojD of spores is produced. Local Dissemination.—Dr. Thaxter states that^^the local dissemination of smut is due to four princii^alcauses. First, through agricultural implements; plows,harrows, weeders, rakes, etc., which spread the soil con-taining smut spores, both by scattering the surface earthover a smutted field, and, unless they are thoroughly. FIG. 68. 0>ION SMUT. a. Spore; 6, spore germinating; c, sporidiagerminating. Magnified. starting from the seed. This THE OXIOX SMUT 155 cleaned, by carrying earth containing smut spores intofields subsequently worked upon. Secondly, throughthe adherence of the same smutted earth to the feet ofmen and farm animals, and its consequent transportationfrom one part of a field to another, or to different fields;an agency by no means unimportant. Thirdly, thesmut spores may be readily washed, with surface earth,fiom higher to lower ground, as is a matter of commonol)servation. Fourthly, popular opinion to the contrary,the spores being practically imponderable, may be readilyblown, with other dust-like material, either about thesame field, or into adjoining fields. The reason thatthis mode of dissemination is of less importance thansome others lies, proba
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
