ORCHARD INSECTS 



305 



to be more abundant on the flower buds and blossoms than 

 the other species. 



The Black Peach-aphis * (42) attacks the roots, tender 

 shoots and foliage of the peach. Young trees suffering from 

 its attacks on the roots have a yellowish sickly foliage and 

 are often much injured before its presence is suspected. 

 Usually, however, the numerous aphides on the leaves will 

 indicate the probability of their also being on the roots. In 

 early summer the aphides 

 cluster on the tender 

 shoots at the crotch of 

 the tree and on the lower 

 limbs and soon form a 

 disgusting black mass 

 over the young leaves, 

 which are tightly curled 

 up from the injury. On 

 young trees, both in the 

 nursery and orchard, this 

 injury is sometimes so se- 

 vere as to kill or severely 

 check the growth. Injury Flo 219 _ The Qat . aphiS; wingless> 



to trees seems to be worst viviparous female greatly enlarged, 

 on light sandy soils. 



Both winged and wingless forms are found on the foliage, 

 but only wingless ones occur on the roots. They are about 

 one-twelfth of an inch long and shining deep brown or black 

 in color when mature. The partly grown aphides, which 

 form the larger part of most colonies, are reddish-yellow or 

 amber colored. The life history of this species is not well 

 known, as neither the sexual forms nor the eggs have been 

 observed. Like the other species it appears on the foliage 

 * Aphis persicce-niger Er. Sm. 



