THE PARASITES OF PLANTS 59 



otherwise they may do much harm before their presence 

 is discovered. 



QUESTIONS AND EXERCISES. 



1. What is a parasite? 



2. How does the potato beetle injure the potato plant? 



3. How may insects that eat leaves be destroyed? 



4. In what way are sucking insects killed? 



5. Tell how to make Bordeaux mixture. 



6. How may oat smut be prevented? Potato scab? 



7. Describe some spraying operation that you have 

 seen. Tell what was the spraying liquid, the method of 

 spraying, and the purpose. 



