FIBER CROPS 363 



infested. The most effective method of combating is believed to be the 

 breeding of resistant varieties. This is done by saving seed from the few 

 plants which have survived a serious attack of the disease. These seeds are 

 again planted in badly infested soil. By planting and selecting for several 

 years varieties of sea island and upland cotton have been produced by the 

 Bureau of Plant Industry which show a high degree of immunity to the 

 disease. 1 



460. BLACK RUST. The attack of the fungus causes the premature falling 

 of the leaves, thus preventing the proper maturity of the plant. Losses may 

 vary from 5 to 50 per cent., and being widely distributed the losses are very 

 heavy. "It may be safely asserted that this disease cannot attack a cotton 

 plant that is in full vigorous growth, but that a sudden checking of growth 

 and lowering of vitality from any cause will render it liable to serious injury 

 if the weather conditions favor the growth of these fungi." 2 The application 

 of potash salts has been found in some cases to have a marked effect in 

 enabling the plant to resist rust. (442) 



461. ANTHRACNOSE. This disease attacks the plant in all stages of growth. 

 It produces death to the young seedling much as in the case of anthracnose 

 of field beans. (270) It causes the bark of the stems to turn to a uniform 

 reddish-brown, and to die. The leaves turn yellow and drop off. It is most 

 conspicuously injurious to the bolls, which, when approaching maturity, may 

 lose their green color and assume especially on the side exposed to the sun 

 a dull red or bronze color. Under favorable conditions for the fungus the 

 characteristic ulcers may appear, but in many cases neither stems nor bolls 

 show them. Affected bolls may open normally and without material damage, 

 but usually they open prematurely, exposing the immature lint which decays. 

 The disease is not usually distinguished from rust, and is not usually recog- 

 nized, but it causes in the aggregate considerable damage. The remedies sug- 

 gested are burning of refuse, planting seed from unaffected plants or the 

 treatment of the seed with a fungicide. If such seed were planted on land 

 in affected cotton the previous year, the treatment would probably be of 

 little value. 



462. COLLATERAL READING. C. W. Burkett and C. H. Poe: Cotton, pp. 

 153-164. New York: Doubleday, Page & Co., 1906. 



J. F. Duggar: Preparation and Cultivation of the Soil for Cotton. In 

 Alabama Sta. Bui. No. 107 (1899), pp. 215-224. 



1 U. S. Dept. Agr. Yearbook 1902, p. 383. 

 2 Alabama Sta. Bui. No, 107 (1899), p. 302, 



