Diseases of Plants 



307 



Univ. of Wis. Agrtc. Ex-pt. 



FIG. 172. In a field of cabbage that was almost entirely destroyed by yellows, 

 a plant that had formed a good head was found. This plant was saved for seed. 



The most successful truck growers often spray crops 

 subject to diseases that can be thus controlled, whether 

 disease is present or not. They do this to prevent any 

 appearance of disease. The home gardener should be 

 prepared to use fungicides whenever diseases appear that 

 can be thus controlled. Children should not be intrusted 

 with the task, but should have the help of some older 

 person, as a parent, teacher, supervisor of garden work, 

 or scoutmaster. 



(5) Varieties resistant to disease. Sometimes certain 

 plants of a crop are able to resist the attacks of a parasite, 

 while the greater number of sister plants all about 

 suffer or die. If seed is saved from these more resistant 

 plants, a highly resistant variety may be obtained. 

 The work of developing such resistant strains is best 



