246 



AGRICULTURE ON THE PACIFIC SLOPE 



OTHER DISEASES 



Leaf curl. This disease is caused by a fungus which grows 

 mjthejgaf^and causes it to curl up; it is especially common 

 on peach trees. It may be entirely prevented by the use of/ 



Bordeaux mixture in/ 

 the spring before the 

 buds swell. 



Leaf spot. Many 

 kinds of fungi cause 

 leaves to become 

 spotted. They at- 

 tack especially ber- 

 ries, celery, beets, and 

 carnations. As a 

 rule, they may be 

 checked by spraying 

 with Bordeaux mix- 

 ture. 



Wilt. This is 

 caused by a fungus 

 which grows in the 

 water ducts of the 

 plant, so that they 

 are unable to carry 



enough water to the leaves. The whole plant gradually 

 sickens, wilts, collapses on the ground, and dies. 



Watermelons and tomatoes are attacked by this disease. || 

 When it attacks the tomato it is called summer blight (for/^ 

 winter blight, see page 234). 



Spraying for this disease is useless. The seed bed should 

 be made with soil free from the fungus. (California Experi- 

 ment Station, Bulletin 175; Idaho, 31.) 



FIG. 146. Pear scab. 



