INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 91 



THE OLEANDER OR MILKWEED APHIS 



A phis nerii Fonscolombe 



(Aphis httcscens Monell) 



(Fig. 73) 



Description.— The apterous form is deep yellow with dark antennas 

 and the cornicles, head and leg joints dusky. The winged form is 

 also yellow with black spots on the thorax, a black blotch at the 

 base of each cornicle and dark head, antennas, cornicles and leg 

 joints. 



Life History. — In the spring the insects appear upon the tender 

 shoots of the oleander, indicating that the over-wintering eggs were 

 laid upon this plant in the fall. Later in the spring the lice migrate 

 to the various species of milkweed where they remain throughout 

 the summer or until the plants die in the fall. They then migrate 

 to the oleanders where true sexual forms are born and the over-winter- 

 ings eggs are laid. 



Fig. 73. — The oleander or milkweed aphis, Aphis nerii Fonsc. Greatly enlarged. 

 (Author's illustration, P. C. Jr. Ent. ) 



Distribution. — This louse occurs throughout the entire State. 



Food Plants. — The buds and terminal shoots of the oleander and 

 the various species of milkweed are attacked. 



Natural Enemies. — The common ladybird beetles prey upon this 

 species to some extent, the internal parasites, Aphidius testaceipes and 

 Charips xanthopsis, and Syrphid flies, especially Syrphus americanus, 

 also prey upon it. Charips xanthopsis is probably secondary. 



THE BLACK PEACH APHIS 



Aphis persicce-niger Smith 

 (Fig. 74) 



Description. — The full-grown winged and apterous forms are about 

 £ inch long, robust and shiny black in color. The young are reddish- 

 yellow or brownish and are always more abundant than the shiny black 

 adults. The shining black color of the adults occurring on the peach 

 make the determination of the species quick and certain. Like the 

 woolly apple aphis, it has a root and an aerial form and is responsible 

 for much damage, especially to young trees. 



