40 MISCELLANEOUS PAPERS. 



EFFORTS TO CONTROL THE DISEASE. 



Our investigation of this disease, including the tests of possible 

 methods of prevention or control, is not yet complete. A consider- 

 able variety of tests has been made in the application of various 

 fungicides and other chemicals and fertilizers to the soil, and attempts 

 have also been made to secure by selection a race or variety of cotton 

 that might be immune or show some degree of resistance to the dis- 

 ease. Neither of these lines of investigation has yet given promise of 



success. 



ROTATION OF CROPS. 



It is generally knowTi to planters familiar with root-rot that it does 

 not affect grasses and grains, and when such crops are grown upon 

 infected land for a few years the succeeding cotton crop is not likely 

 to siiffer so badly. The beneficial results from such rotations alone 

 are, however, not always uniform or satisfactory. 



AERATION OF THE SOIL BY DEEP PLOWING. 



Field and laboratory investigations, coupled w^th the experience 

 of practical growers, have led the writers to conclude that lack of 

 pro]>er aeration of the soil is one of the most important factors favor- 

 ing the development of the root-rot fungus. Deeper plowing than 

 that usually practiced in ordinary cultivation methods improves the 

 aeration of the soil and was therefore tried. 



Three series of experiments were conducted, consisting of (1) deep 

 fall plowing, the land being plowed to a depth of 7 td^O inches on 

 December 7 and 8, 1905, (2) deep spring plowing, and (3) spring 

 subsoiling. 



DEEP FALL PLOWIXG. ' 



The experiment in deep fall plowing was carried on near Luling, 

 Tex. An area was selected where the cotton was nearly all killed 

 by the root-rot during the previous season. Three acres of tliis field 

 were plowed 7 to 9 inches deep ; the remainder was given the ordinary 

 preparation and cultivation, being simply bedded up with a "middle 

 buster" in the spring. The cotton on both plats was planted at 

 the same time and treated in the same mamier during the season. 

 On October 25, 1906, by an actual count of the plants in 15 rows of 

 each plat, representing the average condition, onl}^ 12 per cent of 

 the plants on the deep-plowed plat were found to be dead, while on 

 the check plat adjoining, which had received ordinary preparation, 

 96 per cent of the plants had been killed by the disease. 



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