178 FRIENDS AND ENEMIES OF PLANTS 



EXERCISES 



1 . Secure and name ten common weeds of your locality. Tell where you 

 found them. 



2. Examine the fruit trees closely and report what diseases are found. 



3. Secure specimens of mold, and examine them with a microscope. 



4. Secure specimens of yeast and examine them with the microscope. 



QUESTIONS 



1. Into what two great classes may the enemies of cultivated plants be 

 divided? 



2. Give the divisions and subdivisions of the first class, and also of the 

 second class. 



3. Describe the fungi in general. 



4. Discuss (a) mold, (6) yeast, (c) bacteria. 



5. Discuss (a) agents of fermentation, (6) agents of disease, (c) agents of 

 nitrification. 



6. Describe yeast. 



7. Discuss (a) fire blight, (6) smuts, (c) rust. 



8. Discuss (a) brown rot, (6) black rot, (c) bitter rot. 



9. Describe (a) the apple scab, (6) the peach leaf curl, (c) the wilt. 



10. Discuss (a) potato scab, (6) potato blight. 



11. Describe (a) club root, (6) black knot. 



12. Discuss weeds. 



13. Why should we check their growth? 



14. Are weeds ever beneficial ? 



15. Name the three general classes of weeds. 



16. Describe some of the special weed forms. 



17. If the loss caused by weeds is fifteen bushels of corn to the acre, 

 what will be the loss on twenty acres if corn is worth forty cents per bushel ? 



18. If the' corn is too thick in a field, is it not its own worst weed ? 



19. What weeds are most common on the farms near the school ? Ask 

 farmers what they are doing to control them. Find which ones have few 

 weeds in their crops. Are they the most thrifty farmers ? Why have they 

 fewer weeds ? 



REFERENCES 



Weeds: and How to Kill Them, Farmers' Bulletin No. 28. 



Weeds Used in Medicine, Farmers' Bulletin No. 188. 



Fungicides and Their Use in Preventing Diseases of Fruits, Farmers' 

 Bulletin No. 243. 



The Prevention of Wheat Smut and Loose Smut of Oats, Farmers' Bulletin 

 No. 250. 



Potato Diseases and Treatment, Farmers' Bulletin No. 91. 



Cyclopedia of American Agriculture, L. H. Bailey. 



