IOO KNAPP METHOD OF GROWING COTTON 



to the disease. Another means suggested 

 for the control of this disease is by practising 

 crop rotation, using in the rotation crops that 

 are not affected by the wilt fungus and the 

 nematode worm a very small worm which 

 attacks the roots of plants causing root knot. 

 It is claimed that the attack of this worm on 

 the cotton roots makes it easier for the wilt 

 germ to enter. The plants that may be used 

 in a rotation to free the land of wilt are: corn, 

 wheat, oats, rye, iron cowpea, Brabham cow- 

 pea, velvet bean, beggar weed, and grasses. 



The United States Department of Agri- 

 culture has developed two varieties of cotton 

 which show great resistance to wilt, viz., 

 Dixie and Dillon. 



Cotton Rust. Cotton "rust" first makes an 

 outward appearance by a mottled yellowish 

 color of the leaves in dry weather or a sudden 

 blackening and shedding of the foliage in wet 

 weather. This disease is probably due to a 

 poor mechanical condition of the soil and the 

 lack of some plant food element, usually potash. 

 Soils affected with rust are greatly benefited by 

 turning into them heavy crops of vegetable mat- 

 ter, and by a rather liberal application of potash. 



