INJURIOUS AND BENEFICIAL INSECTS OF CALIFORNIA. 



97 



are light with dark tips. The males which appear in the fall greatly 

 resemble the females, but are much smaller, slender and have wings. 

 The eggs are oval and black. This species is distinguished from the 

 black peach aphis (Aphis persicce-niger Smith) by the long cylindrical 

 honey tubes which usually point inwardly. 



Fig. 78. — The black cherry aphis, Myzus cerasi (Fab.), on cherry 

 leaf. Young- and mature wingless females. Enlarged three times. 

 (Original) 



Life History. — The eggs are deposited during the fall in the crevices 

 of the bark or upon the young twigs at the bases of the fruit spurs. 

 They hatch in the spring about the first of March when the buds 

 open and the young begin feeding at the base of the flowers and 

 leaves or enter the opening buds and feed upon the latter. As the 

 leaves appear they become infested by succeeding broods. The insects 

 may be found upon the trees throughout the entire summer and often 

 do considerable damage by curling and dwarfing the foliage. True 

 sexual males and females appear in the fall, mate and the latter 

 deposit the over-wintering eggs. 



Nature of Work.— The plant lice collect in great numbers near the 

 tips of the branches, small shoots and spurs, causing the leaves to 

 curl and eventually drop. Much damage may be done where severe 

 infestation occurs, especially in nurseries. 



Distribution. — This aphis occurs quite commonly throughout the 

 central and northern parts of the State. 



Food Plant.— The cherry is the only recorded host. 



7— 136G4 



