518 CITRUS FRUITS AND THEIR CULTURE. 



Remedies: White fly is difficult to control. Little 

 can be done when the insects are flying about, and all 

 remedial work must be undertaken during the larval and 

 pupal stages. During these stages the insects are at rest 

 on the under sides of the leaves. Fumigation or spraying 

 at this time is effective. The best time for fumigating is 

 from the middle of December to the end of February. 

 Spraying may be done during the same period or in the 

 summer. When the insects are pupating use solutions 

 (6), (8) or (9). 



Strong effort should be made to introduce such bene- 

 ficial fungi as the Eed Aschersonia and the Brown fungus 

 This may be successfully done in a number of ways. See 

 page 550. 



The complete defoliation or destruction of all infected 

 trees and plants during the periods recommended for fumi- 

 gating will insure the destruction of the insects. Some- 

 times this is feasible. The principal host plants are all 

 species of citrus, Chinaberry tree, Umbrella China tree, 

 Cape Jessamine and occasionally cherry laurel, Magnolia 

 fuscata, and Japan honeysuckle. 



Orange Rust Mite and Lemon Silver Mite. (Phy- 

 toptus oleivorus Ashmead.) This mite is quite minute, 

 being 0.14 mm. in length. In outline its body is rather 

 wedge-shaped, widest near the head and tapering grad- 

 ually to the posterior end, which is provided with a pair 

 of appendages. The abdomen is divided into about thirty 

 segments. The legs are four in number, placed close 

 together on the anterior portion. 



The young insects are bright yellow in color, becom- 

 ing darker as they grow older. The eggs are yellow in 

 color, spherical and transparent, and are deposited by the 

 adult singly or in clusters on the leaves. 



