148 MANUAL OF FRUIT DISEASES 



Control. 



To the grower who contemplates planting an orchard in the 

 Southwest it is advised that the list of possible host-plants be 

 carefully consulted before proceeding. If it is determined that 

 the pathogene is present in the soil of the site proposed for the 

 orchard, it is best to wait from three to five years before plant- 

 ing. Select trees from a nursery known to be clean. Orchard 

 cultivation gives proper aeration for the roots and at the same 

 time presents conditions unfavorable to the fungus. Deep fall 

 plowing has been advised for cotton ; this measure may assist 

 not only the cotton-grower but also his neighbor who may wish 

 to grow apples. In severe cases the fungus may be isolated by 

 digging trenches about infected trees, going as deep as the roots 

 penetrate into the soil. All weeds, most particularly the sida, 

 should be destroyed. A tree once found diseased ordinarily 

 cannot be saved ; this is due to the fact that there is usually no 

 external indication of the trouble until the whole root-system is 

 practically destroyed. Diseased and dead trees should be 

 removed and destroyed. If a stump is left, it is recommended 

 that the dirt be removed from about the roots, allowing them 

 to dry, then that the whole stump and its root system be burned. 



REFERENCES 



Shear, C. L., and Miles, G. F. Miscellaneous papers. V. The control 



of Texas root-rot of cotton. U. S. Agr. Dept. Plant Indus. Bur. 



Bui. 102 : 39-42. 1907. 

 Pammel, L. H. Cotton root-rot. Texas Agr. Exp. Sta. Bui. 7 : 5-30. 



(Also Kept. 2 : 61-86.) 1890. 

 Galloway, B. T., and Woods, A. F. Diseases of shade and ornamental 



trees. Root diseases. Southern root-rot. U. S. Agr. Dept. 



Yearbook, 1896 : 248-249.' 1897. 

 Stevens, F. L. Ozonium omnivorum. In The Fungi which Cause 



Plant Disease, pp. 662-663. 1913. 

 Duggar, B. M. Root rot of cotton and alfalfa. In Fungous Diseases 



of Plants, pp. 479-481. 1909. 



