ii2 Diseases of iruck Crops 



wilting is more sudden, and the stems bend into a 

 curve. In this case affected seedlings seem to preserve 

 their natural green color. The disease is confined 

 to the root fibers, which turn rusty brown or black. 

 In severe cases, all that is left is a charred stub. 

 The affected tissue is dry, although several soft rots 

 may follow the primary injury. For a description 

 of the causal organism see garden pea, p. 275. 



Control. For seed beds the soil should be treated 

 with steam or formaldehyde as described in pages 

 53~59- For large beds the application of acid phos- 

 phate at the rate of one thousand pounds per acre 

 will be found beneficial. The treatment, to be effec- 

 tive, must be given to soils not too alkaline. Where 

 the soil is strongly alkaline, heavier quantities of 

 acid phosphate should be applied, so that the treated 

 soil may become distinctly acid. 



STEM ANTHRACNOSE 

 Caused by Vermicularia dematium (P.) Fr. 



Symptoms. Anthracnose is apparently a seedling 

 disease of little importance. It appears as numerous 

 black spots on the stems of the young plants. These 

 enlarge and very frequently end by girdling and kill- 

 ing the entire stem. 



Control. The disease may be controlled by spray- 

 ing with Bordeaux mixture as soon as the plants are 

 about three weeks old. Spraying should be repeated 

 every two to three weeks until about August ist. 



