282 



NUTS AND SUBTROPICAL FRUITS 



Enemies. — Many forms of scale insects attack oranges and 

 other citrus fruits. There are also red spiders, plant lice, rose 

 beetles, and other insects attacking the orchards. The methods of 

 control are spraying and fumigating under movable tents with 

 hydrocyanic acid gas. Spraying in Florida and fumigation (Fig. 

 199) in California are the general rules. 



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Fig. 197.— Oranges must be picked from the trees. Those which fall to the ground are 

 considered worthless. (U.S.D.A.) 



Common diseases of the trees are: gum disease, root-rot, trunk- 

 rot, wither-tip, twig-blight, melanose, and canker. 



Frost is the most serious enemy of citrus fruits in America. The 

 chief remedy is to have the wood well ripened up before winter. 

 The use of orchard smudges is often very effective. Fruits are 

 picked from near the ground first, to avoid frosting. 



Grapefruit.— This is one of the citrus fruits of Florida, California, 

 Arizona, and the West Indies. It is well known in all markets of 



