316 CITRUS FRUITS 



tables worked out by the United States Department of 

 Agriculture and the various state experiment stations, and 

 these should be consulted for a more detailed study of 

 fumigation. 



The fumigation gives better results and produces less 

 injury to the foliage if it is done at night instead of in the 

 daytime. 



The season of the year at which fumigating is done depends 

 upon. the life history of the insects and the condition of the 

 tree. The fumigation should be carried on when the insects 

 are in the most tender stage and can be easily killed, and 

 the tune will vary slightly for each insect. However, from 

 August to January seems to be the time which gives the 

 most satisfactory results. 



The dosages as well as the length of time vary with the 

 different scale insects. This phase can be learned in some 

 more complete treatise on the subject. 



REVIEW QUESTIONS. 



1. Name the fruits included in the citrus class. 



2. Why is the citrus industry confined to certain special districts? 



3. How does the grape fruit differ from the orange? 



4. Discuss the propagation of the citrus fruit. What form of budding is 

 used? 



5. What is the best type of soil for the citrus fruit? How does the sub- 

 soil regulate the value of the top soil? 



6. Why is good cultivation essential? 



7. How should a citrus orchard be planted? 



8. Discuss the curing of citrus fruits. How does the curing of the orange 

 differ from that of the lemon? 



9. What method of picking is used for the lemon? Why? 



10. How does the picking of the orange differ from that of the lemon? 



11. What is the value of washing citrus fruits? In what solution is the 

 washing done? 



12. Discuss the grading of citrus fruits. 



13. Discuss the packing of the lemon, grape fruit and orange. 



14. Discuss the principal diseases and give the methods of control. 



15. What class of insects is the most injurious to the citrus fruit? Why? 



16. Discuss the fumigation of a citrus orchard. 



17. Why is fumigation used instead of spraying? 



18. When is the best time to fumigate? Why? 



19. What is the most destructive citrus insect in Florida? 



20. Give the life history of the whitefly. 



21. What method of control has proved the most effective with the 

 whiteflies. 



22. Discuss the various ways of controlling the different diseases on the 

 citrus fruit. 



