Fungous diseases of plants . erature changes nor general differences in soil condi-tions seem to be of special consequence. Plants in sandy regionsmay be more readily wilted than those in soils more retentive ofmoisture, but, at the same time, the fungus evidently does nogreater damage ultimately in one soil than in the other. Parts of the plant affected. The wilt disease of cotton wasfirst described as a Frenching (Atkinson). Cotton plants in asc:()MYcp:tes 235 the heavy soils of central Alabama were somewhat peculiarlyaffected by this fungus. There is first a yellowing and finallya drying ou
Fungous diseases of plants . erature changes nor general differences in soil condi-tions seem to be of special consequence. Plants in sandy regionsmay be more readily wilted than those in soils more retentive ofmoisture, but, at the same time, the fungus evidently does nogreater damage ultimately in one soil than in the other. Parts of the plant affected. The wilt disease of cotton wasfirst described as a Frenching (Atkinson). Cotton plants in asc:()MYcp:tes 235 the heavy soils of central Alabama were somewhat peculiarlyaffected by this fungus. There is first a yellowing and finallya drying out of those portions of the leaves farthest from themain fibrovascular bundles, that is, between the lobes. Latersuch leaves might fall, or the whole plant might become wilted,and finally brown and dead. In other regions of the country thewilting is much more a characteristic appearance,—the dis-ease being scarcely noticeable, except in a stunted condition ofthe plants, until finally wilting results. In general, the disease. Fig. 98. Cotton Plants of the Same Age: to the Left, Healthy;TO the Right, affected by Wilt. (Photograph by W. A. Orton) is t}pically that of a wilt in the case of both cowpeas and water-melons. The affected plants have therefore the appearance whichany plant would have when deprived of its water supply, that is,a general wilting and drying up. On cutting the stem, or eventhe leaf petiole of affected cotton, a darkening of the xylem por-tion of fibrovascular bundles is shown, and this is an excellentindication of the presence of this fungus, since no other diseasenow known discolors the xylem in this way. In some casesplants affected and dwarfed show little or none of the charactersin the stem, yet an examination of the larger root branches andeven the tap root would show the characteristic appearance. In 236 FUNGOUS DISEASES OF PLANTS 1 spite of the fact that the disease may sometimes be suddenlymanifested, yet it is certain that it has a long period of i
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