FIBER PLANTS 403 



corn; 1906, planted to wheat, followed by sorghum the 

 same season; 1907, cotton again planted, with the result 

 that, as nearly as could be estimated, less than 5 per cent 

 of the cotton was dead at the close of the season. 



" Land badly infected with the root rot was plowed seven 

 to nine inches deep November 11, 1906, at Petty, Tex. In 

 experiment No. 1 the deep-plowed plat showed 42.75 per 

 cent less dead plants than the adjoining check plat which 

 received the customary tillage. In experiment No. 2 the 

 deep-plowed plat showed 43 per cent less dead plants than 

 the adjoining check plat, and in both cases a much larger 

 amount of cotton was produced on the dead plants on the 

 treated plats, because these plants did not die until later 

 than those on the untreated plats, and therefore had greater 

 opportunity to mature their bolls." 



Frosty mildew {Ramularia areola Atk.). — This leaf spot 

 is limited sharply by the smaller veins, and bears upon the 

 lower surface nmiierous colorless spores upon colorless 

 hyphse, thus lending a frosted appearance. Seen from 

 above, the spots are light yellow or of a paler green than 

 the normal leaf tissue. Widespread, though not especially 

 destructive, it does not usually attract the attention of 

 the planter. 



Leaf blight (Mycosphcerella gossypina Atk.) . — The fun- 

 gus which causes this disease was first described from 

 Carolinian specimens in 1883, at which time its presence 

 was recognized in South CaroHna, Georgia, and Florida. 

 The disease prevails in all cotton sections of the United 

 States, appearing first in damp localities upon the lower 

 leaves, and with the progress of the season spotting all the 

 leaves more or less. The leaf spots appear at first as small 



