204 



AGRICULTURE 



grain, such as wheat or oats. When the grain is threshed, these 

 spores adhere to the grains and are planted with them. They 

 develop and attack the young plants. The farmer does not wish 

 to raise a crop of smut to feed upon his grain and lessen its yield. 

 Therefore he should kill the smut spores on infected grain by the 

 use of for'ma lin, as described on page 307 in the appendix. 



Wilt. Wilt is a disease which attacks cotton, flax, tobacco, 

 cowpeas, and other crops. It is caused by bacteria in the soil, 



Courtesy o'i North Carolina Experiment Station 



TOBACCO, SHOWING DIFFERENT STAGES OF WILT 



which enter the plant, probably through the root hairs, and spread 

 up into the stem. There they grow, and choke the passages so that 

 the flow of sap from root to foliage is lessened or stopped. As 

 their supply of water is evaporated, the leaves wilt and wither. 

 Later, the stem blackens and rots. Sometimes only a few plants 

 in a field are affected, sometimes all are attacked. Care must 

 be taken not to spread the disease by carrying infested plants off 

 the field where they grew. They should, if possible, be collected 

 and burned there. 



