THE MONTHLY BULLETIN. 67 



and May, winged migratory females appear, which start colonies upon 

 other trees. The work continues until about the middle of July, when 

 most of the lice leave the tops and again go to the roots. 



Distribution. — This louse is at the present time found in nearly 

 every peach growing county in the State and may be expected to 

 appear in practically any such locality. 



Food Plants. — So far as knowai this louse attacks only peach, plum 

 and nectarine trees, working above ground upon the leaves, twigs and 

 fruit and below ground upon the roots. 



Control. — The control of this louse has caused considerable anxiety 

 in some sections of the State, while in others it is feared no more than 

 the green peach aphid (Myzus pcrsiccn) . The treatment is the same as 

 for the ordinary atrial and root forms. 



Natural Enemies. — Natural enemies play an important part in its 

 control. In Tehama County the larv^ of the syrphid fly {Syrphus 

 americanus) were present in great numbers feeding upon the aphids. 



THE GREEN APPLE APHIS. 



Aphis pomi DeGeer. 



{Aphis mali Fab.) 



(Figs. 55, 56.) 



In order that the readers may get a true idea of the development 

 and habits of plant lice the full life history of this species is given as 

 an example : 



Eggs. — We shall first begin with the small black shiny eggs which 

 are found in great numbers on the smooth bark of the rapidly growing 

 twigs or water sprouts of the apple tree. When these eggs were first 

 deposited, some time during the months of October, November, or as 

 late as December, they were of a beautiful green color, but with age 

 turned to a shiny metallic black. A careful examination in winter 

 of the young twigs and water sprouts of an orchard w^hich was infested 

 with this insect in summer will often show great numbers of these 

 eggs — in some cases completely covering the twigs. 



The eggs themselves are very tiny, not nearly as large as a pin- 

 head, and are long and oval in shape. Only a small percentage of 

 them hatch, and this accounts for the large number necessary to pro- 

 duce so many lice for the coming spring. In the eastern states, where 

 the winters are very severe, it is estimated that only one per cent hatch. 

 In California, however, a much larger percentage is able to withstand 

 our milder climate, and so the succeeding infestations are even more 

 severe here than they are in colder climates. Since such a small per- 

 centage hatch you may marvel at the rapidity in which this insect multi- 

 plies, but this will be brought out in a further study of the life history, 



