318 



TEXAS. 



Texas Agricultural Experiment Station. 



Deparliiinit of A(/rici(lttir(il mid Mcrhdiiicul ('dllcfjc of Tc.ias. 

 Location, Collejje Station. I)ire<tor. F. A. Gulley, M. S. 



BULLETIN No. 7. NOVEMBER, 1889. 



Cotton koot rot, L. H. Pa:\i:mel,* B. Agr. (pp. 5-30), (illus- 

 trated). — This contains an account of the conditions under which the 

 disease occurs, the vai-ious theories regarding its origin, its general 

 characters, the fungus tlioiight to cause the disease, the useful plants 

 find trees and the Aveeds affected hy this fungus, the botanical charac- 

 teristics of the fungus, other fungi found in the roots of cotton, the 

 qualit\^ of the lint of diseased cotton, and experiments with the seeds 

 of diseased cotton Avith fungicides, and in the use of fertilizers and 

 the rotation of crops as preventives. There arc also suggestions as 

 to the treatment of infected forest and orchard trees, and a summary 

 of fifty-seven replies from forty-seven counties in response to a cir- 

 cular sent out by the Station. Numerous references to American and 

 foreign literature on this and kindred subjects are given in foot-notes. 

 The bulletin is illustrated hy hve i)lates, with figures showing portions 

 of diseased plants and views of the fungus in different stages. The 

 following summary is taken, with some alterations, from the bulletin: 



Root rot of cotton occurs in soils of A'arious kinds, but is worse in 

 black, cretaceous soils which are poorly drained. Moisture and heat 

 are favorable to its development, but the character of the forest 

 jjfrowth has nothing to do Avith this disease. " It occurs alike on the 

 mesquite soils of Travis and Hays Counties and the post-oak lands of 

 P^astern and the bois d'aic lands of Xorthern Texas." Theories as to 

 its origin, founded on the chemical constituents of soils, and especially 

 on the " alkali " present in many soils, are not sustained by the facts. 

 Alkali, as the term is used, is very vague and does not apply to the 

 Texas soils where cotton dies from root rot. In California cotton 

 succeeds admirably on '' alkali '' soils, while fibrous-rooted plants do 

 not thrive on such lands. In Texas, on the other hand, the fibrous- 

 i-ooted i^lants, like grasses, do not die from root rot. '' Seedling rot " 

 and " sore shin '' should not be confounded with root rot. '' Seedling 

 rot "■ affects only young plants. The l)acterial disease of corn, de- 

 scribed by Professor Burrill,! sometimes occurs in fields where cotton 

 died the i^revious year from root rot, but is entirely distinct from 

 root rot of cotton, sweet-potato, etc. 



Eoot-rot of cotton is caused by a fungus, Osoiiinni (inr'/comum^ 

 invariably found on roots Avhich have died from this disease. If 



* Mr. Pammel is eng.'iged in special work in botany for the Iowa Station, 

 t See Illinois Station Bulletin No. 6, an abstract of \Abicli is given in tbe 

 Experiment Station Record, Vol. I, No. 4, p. 199. 



