DISEASES OF CROPS 221 



numerous small spots over the surface of the leaves, beginning with the 

 lower and older leaves, causing them to turn yellow and fall. It is one of 

 the most severe diseases and the cause of heavy losses. 



Treatment. Spray with Bordeaux mixture. 



Fusarium Wilt (Fusarium lycopersici, Sacc.). This is a disease in 

 which the fungus works on the inside of the plant, causing it to wilt and 

 die. It cannot be controlled by spraying. Rotation of crops is advan- 

 tageous. 



Bacterial Wilt. See Potato. 



Blossom-End Rot or Point Rot. The cause of this disease is disputed, 

 but it is now generally believed to be due to drought, although it may 

 also be due to other causes. It is a dry black rot starting at the blossom 

 end of the fruit and is often very destructive. It is more serious in dry 

 weather and in dry soils. 



Treatment. Practice thorough cultivation of the soil and remove 

 diseased fruit. 



Anthracnose (Colletotrichum phomoides [Sacc.], Chester). This dis- 

 o;i:-o causes discolored, sunken spots which become centers of decay. It 

 is likely to be very severe in wet weather. 



Treatment. Spray with Bordeaux mixture. 



Fruit Rot (Phoma destructiva, Plowr.). This disease causes a spotting 

 of the leaves and a fruit rot. Caa probably be controlled by spraying with 

 Bordeaux mixture. 



EGGPLANT 



Attacked by several fruit rots and leaf spots which sometimes prove 

 destructive. They can be controlled by the use of Bordeaux mixture. 



PEPPER 



Susceptible to several fruit and stem rots, leaf spots and wilts which 

 can be controlled by rotation of crops and treatment with Bordeaux 

 mixture. 



LETTUCE 



Mildew (Bremia lactucce, Regel). This disease is frequently very 

 destructive. It causes rather large, pale spots, which become yellowish 

 above and fuzzy below. 



Treatment. Good cultural methods for outdoors. Ventilation for 

 crops grown under glass. 



Drop or Wilt (Sclerotinia libertiana, Fckl.). This causes a very pro- 

 nounced wilting and drooping, beginning with the lower leaves and grad- 

 ually spreading throughout the entire plant. 



Treatment. Removal and destruction of the diseased plants and 

 disinfection of soil at that point with Bordeaux mixture. 



NOTE. There are several other diseases of the lettuce more or less 

 important. 



