234 Peach-Growing 



Distribution of black peach-aphis. 



Probably this aphis has been more troublesome in the 

 middle and South Atlantic states than elsewhere, but it 

 is known to occur in Michigan, Colorado, California, and 

 Ontario. As it is a native its distribution is likely to be 

 even more widespread than has been definitely recorded. 



Life history and habits. 



Probably the most serious damage is caused by the wing- 

 less forms on the roots, where they may be found throughout 

 the year. If they become numerous on the smaller roots of 

 a tree, as often happens especially during the second and 

 subsequent seasons after planting, they sap its vitality to 

 such an extent that the tree becomes weakened, the foliage 

 is small, scanty, and yellow, and the tree has a generally weak 

 and unthrifty appearance. 



The aphides may be found on the affected roots at any 

 time in the season. They are active throughout the growing 

 period. In the spring, with the beginning of growth, some 

 of them craw^l to the branches and begin feeding on the 

 new twigs and leaves. In May, in the latitude of New Jersey, 

 the insects may become quite numerous on the new growth, 

 and by this time the winged forms which appear only on the 

 twigs and leaves develop. By June the winged insects 

 are migrating to other trees. These forms produce a brood 

 of wingless insects, which in turn soon make their way to 

 the roots. Thus, by the middle of the growing season there 

 may be no indication on the parts of the tree above ground 

 that the insect is present. 



Methods of control. 



The first consideration is prevention rather than control. 

 By planting trees free from the insect, the danger of injury 



