146 SPRAY MACHINERY AND SPRAY MATERIALS 



The strength recommended is 2 pints of 40 per cent, 

 fomaldehyde to 30 gallons of water, heated to a temperature 

 of 118 to 122 F. and dipped for two minutes. Remove the 

 potatoes, pile 6 to 8 inches deep and cover them with wet 

 sacks for an hour, then let them dry. 



REVIEW QUESTIONS. 



1. Name six different kinds of spray machines. 



2. Why are the small hand sprayers not as effective as the power 

 machines? 



3. How does the bucket sprayer differ from the automatic sprayer? 



4. What advantage has the automatic sprayer over the bucket sprayer? 



5. How does the barrel sprayer differ from the twin-cylinder hand 

 sprayer? 



6. What three kinds of power sprayers are made and upon what is the 

 difference based? 



7. Name the four kinds of valves found in a spray machine? 



8. What material is best suited for making the valve seat? 



9. Describe the most effective agitator. 



10. What material is best suited for making a spray tank? Why? 



11. Name and describe several kinds of spray nozzles? 



12. Why are the nozzles so very important in spraying? 



13. What is the spray rod, and what is its function? 



14. Name two poisons for biting insects. 



15. What is meant by a contact and a stomach insecticide? 



16. Why should stone lime be added to Paris green when spraying? 



17. When should white hellebore and pyrethrum be used in spraying? 



18. Give the formula and tell how lime-sulphur wash is made? 



19. On what kind of insects is kerosene emulsion used? 



20. How does kerosene emulsion differ from carbolic acid emulsion? 



21. Give the formula for Bordeaux mixture and tell how it is made. 



22. What is the difference between commercial lime sulphur and self- 

 boiled lime sulphur? 



23. What combinations of insecticides and fungicides are possible, and 

 why are they made? 



24. What is meant by fumigation and what is controlled by it? 



25. Tell how seed potatoes are treated and what is gained by this treat- 

 ment. 



