THE ANGULAR LEAF-SPOT OF COTTON I TYPE 



321 



nomenally large and interferes with the making of a crop, as now 

 seems probable; and especially, if this schizomycete generally 

 paves the way for the entrance of the destructive boll fungus, 

 Glomerella gossypii {Colletotricum gossypii Southworth), as 

 Mr. Orton believes or did believe at one time, then indeed it is a 

 very serious enemy of cotton growing. This much is certain, 



Fig. 244. — Cotton leaf inoculated May 4, 1915, from a windowed colony. Photo- 

 graphed June 26, 1915. Time, 53 days. 



the anthracnose fungus and the schizomycete often occur 

 together on the bolls in such a w^ay as to indicate that the 

 first invasion was bacterial. Further studies are necessary. 

 Weather conditions have much to to with the prevalence of 

 the disease. 



Cause. — This disease is due to Bacterium malvacearum EFS. 

 This organism is a yellow, Gram-negative, non-acid-fast 



and fixed in Carnoy's fluid, April 5. Sectioned from paraffin. Amyl-Gram 

 stain. Stomatal region pushed up. X 1000. From a photomicrograph by 

 the writer. 



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