146 FIELD CROPS FOR THE COTTON-BELT 



181. Symptoms. — One of the first symptoms of this 

 disease is the dwarfing of the plants. Many of the badly 

 affected plants wilt and die. In other cases the plants 

 may show no striking symptoms other than those exhibited 

 by the roots. It has been noticed that when the affected 

 roots begin to die, new roots are sent out finally resulting 

 in a bushy and somewhat tailgled root-system. 



As previously mentioned, root-knot is often associated 

 with cotton-wilt, in which case it increases the injury 

 due to the latter disease. The wounds which the nema- 

 todes make in the roots furnish points of entrance for the 

 wilt fungus, which then completes the destructive work. 



182. Remedy. — Root-knot can be controlled by the 

 use of proper crop rotations. In arranging this rotation 

 one must remember that only such crops as are immune 

 to the nematode attacks must be grown until the worms 

 are sufficiently starved out of the soil to permit the suc- 

 cessful growth of susceptible crops. It is also important 

 that any weeds attacked by these worms be eradicated. 

 In ridding the soil of the nematode disease, many farmers 

 grow small-grains on the land during the winter months, 

 and occupy the land during the summer with sorghum, 

 millet, June corn, or the resistant varieties of cowpeas. 



COTTON ANTHRACNOSE {Glomerella gossypii) 



183. Occurrence. — • Anthracnose, often known as 

 pink-boll or boll-rot, occurs very generally throughout 

 the cotton-belt. It is estimated that the annual loss from 

 the disease amounts to several million dollars. Seasonal 

 conditions determine, to a large extent, the prevalence of 

 this disease. A very dry season retards the development 

 of the spores and affords a natural means of control. Wet 

 seasons greatly augment the injury from anthracnose. 



