MALFORMATIONS OF COTTON PLANTS 



IN HAITI 



A New Disease Named Smalling or Stenosis, Causing Abnormal 



Growth and Sterility 



O. F. Cook 

 U. S. Department of Agrieidture 



APECULLAR disorder of cotton 

 plants was found in China in 

 1919. as described in the Jour- 

 nal OF Heredity for March, 1920, un- 

 der the name club-leaf, or cyrtosis. 

 After growing normally as seedlings and 

 into the stages of flowering and fruit- 

 ing, there is an al)rupt change to 

 an abnormal habit of growth with the 

 branching irregular, the leaves con- 

 tracted and distorted, and the floral 

 buds mostly aborting. The danger of 

 introducing such a disease into the 

 United States was recognized. 



A similar afifection of cotton, with 

 even greater extremes of reduction of 

 the leaves and other organs, was seen 

 recently in the north-central part of 

 Haiti. Several fields were visited July 

 •27, 1923, in the vicinity of St. Michel, 

 within a radius of about three miles. 

 Definite indications of the disease were 

 found in all of the fields, but with wide 

 diff^erences in the numbers of plants 

 affected as well as in the nature and 

 extent of injury of the diseased indi- 

 viduals. 



Though most of the cotton was of the 

 Meade variety. Lone Star, Durango, 

 Acala and other varieties of American 

 upland cotton were represented, as well 

 as Sea Island cotton and the type that 

 is considered as native Haitian cotton. 

 In some of the fields there were many 

 hybrids between the Meade Upland cot- 

 ton and the Sea Island and also crosses 

 of these types with the Haitian cotton. 

 A special interest attaches to the 

 Haitian cotton on account of its appar- 

 ent immunity to the disease. The de- 

 velopment of uniform productive 



strains of this cotton or of some other 

 immune type is the obvious way of 

 controlling the disease. 



Other plantings of Meade cotton at 

 Bon Repos, a few miles from Port-au- 

 Prince, showed no such deformities. 

 This district is in the plain of Cul-de- 

 Sac. nearly at sea level, while the St. 

 Michel district has an altitude of about 

 1,200 feet and represents the interior 

 plain or plateau region of Haiti. Un- 

 like most parts of Haiti, this interior 

 plateau region is but little inhabited. 

 It is a gently rolling grass-covered 

 country, not unlike the South Texas 

 prairies. A large cotton-growing enter- 

 prise was established at "St. Michel by 

 American capital during the war period. 

 The presence of this disease is a factor 

 that could not be reckoned, as there is 

 no similar disease in the American cot- 

 ton belt. Also the dominant grasses 

 of the Haitian savannas, identified by 

 Mrs. Agnes Chase as Thcmeda arguens 

 and Sporobolns indicus, are much more 

 refractory than the Texas prairie 

 grasses. 



Comparison with the Chinese Disease 



The two disorders show very similar 

 results in altering the behavior of the 

 plants, and undoubtedly belong to the 

 general group of so-called "mosaic" 

 diseases, which in some cases are 

 caused by leaf -hoppers. The affected 

 plants usually are more or less de- 

 ficient in chlorophyll and show differ- 

 ent shades of color with angular spots 

 or areas, some of lighter and some of 

 darker green, fitted together like a 

 mosaic. In Haiti this feature is less 



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