Orange. 321 



Leaf Spot (Colletotrichum adustum, Ellis). Description. 

 Leaf spot attacks both wild and sweet oranges. It first pro- 

 duces on the leaves light green spots which are about an eighth 

 of an inch in diameter. These enlarge till they are fully an 

 inch across, the older portions becoming brown and studded 

 with small black dots. This disease is not as yet very serious. 



Treatment. The two diseases here mentioned have appar- 

 ently not been thoroughly treated, so that all recommendations 

 must be founded upon the experiences gained in treating other 

 plants. The copper compounds will probably prove most effi- 

 cient in controlling the diseases, the applications being com- 

 menced a week or two before the troubles first appear. 



INSECT ENEMIES. 



Leaf Notcher (Artipus Floridanus, Horn). Description. The 

 adult is a small insect about a quarter of an inch long; it is of a 

 metallic greenish-blue color. It feeds upon the foliage of the 

 trees, beginning at the edges of the leaves. 



Treatment. Jarring the trees has been recommended, and 

 it seems probable that applications of the arsenites would prove 

 effectual in destroying the pests. 



Mealy-wing (Aleyrodes Citri). Description. These minute 

 white flies frequently appear in such numbers upon orange 

 foliage that the tree may be considerably weakened by them. 

 Related forms are common in northern greenhouses, and 

 plants are often seriously injured by their work. In the South 

 the insects generally pass the winter in the larval stage. In 

 early spring they pupate, and the adults appear during March 

 and April. Eggs are laid in abundance on the under side of 

 the leaves. They soon hatch, and the larvae, on account of their 

 transparency, may be present in swarms, and still pass unnoticed. 

 They suck the juices from the leaves, and secrete a honey-dew 

 upon which a dark fungus soon grows. There are three gener- 

 ations each year in the South. 



Treatment. The insects do not yield readily to treatments of 

 kerosene emulsion, but the resin wash smothers the immature 

 forms. Under glass, other species are easily destroyed by 

 tobacco smoke. 



Mite ; Leaf-mite ; Spider ; California Spider ; Red-spotted 

 Mite; Red Spider (Tetranychus Q-maculatus, Riley). Descrip- 



T 



