INSECTS IN RELATION TO HUMAN WEALTH 573 



4. How can insects that are not important in one region be of great 

 injury in another region? 



5. How can insects that are harmless in one period become injurious 

 at another time ? 



6. What kinds of insects do their harmful work in the adult stage ? 

 in the larval stage ? in every stage ? 



7. What is the best time to fight a particular kind of insect pest ? 



8. What is the best time for combating all insect pests ? 



9. How does spraying kill insects ? Why can we not use the same 

 kind of spray mixture on all kinds of plants? against all kinds of 

 insects ? 



10. How does insect powder kill insects ? 



IL Under w^hat conditions is rotation of crops a good way to kill off 

 insects ? How does rotation of crops do it ? 



12. How does fall plowing help to combat insect pests ? 



13. Why is it desirable to give the chickens the run of a plowed field 

 before planting? after planting? 



14. What must we know about a new insect pest before we can fight 

 it successfully ? How can we find out ? 



15. What are the chances that man's fight against insects will some 

 day be finished ? Why ? 



REFERENCE READINGS 



Fanners^ Biilletin 740, House Ants. 



Farmers' Bulletin 1037, White Ants as Pests. 



Farmers' Bulletin iioi, Argentine Ant as a Household Pest. 



Farmers' Bulletin 1346, Carpet Beetles and their Control. 



Farmers' Bulletin 1353, Clothes Moths and their Control. 



Farmers' Bulletin 801, Mites and Lice. 



Farmers' Bulletin 12^4, The Corn-borer. 



Farmers' Bulletin 1371, Diseases and Insects of Garden Vegetables. 



United States Department of Agriculture. Bulletin 824, Insect Powder ; 



Bulletin J057, Red-Cedar Chests as Protectors against Moth Damage. 

 Farmers' Bulletin 1326, Control of the Codling Moth. 

 United States Department of Agriculture. Yearbook for 1916. Reprint 



704, Practical Use of Insect Enemies of Injurious Insects. 

 Price List 41. Insects (from Superintendent of Documents). 



