18 FARMERS BULLETIN" 804. 



A second dark brown or blackish species which occurs occasionally 

 upon apples is the bur-clover aphis.^ It is sometimes met during the 

 spring upon apple foliage. 



Still another species, the wild-carrot aphis,' occurs commonly on 

 the apple in the fall, particularly as the winged form. Its summer 

 hosts are the wild carrot and related plants, and the winged forms fly 

 to honej'suckles, but occasionally select apples. 



The thorn-leaf aphis ^ also is found occasionally upon apple. Its 

 life history is discussed under aphids attacking the quince. 



QUINCE APHIDS. 



Two species of aphids which ha^■e been discussed under apple occur 

 commonly also upon quince foliage — namely, the green apple aphis 

 and the oat aphis. Their life histories are similar on quince and 

 ajjple, and the same remedial measures apply. 



THE THORN-LEAF APHIS. 



The thorn-leaf aphis,^ called also the long-beaked clover aphis, is 

 most common upon hawthorn trees. Although first found upon 

 thorn, it is not uncommon upon quince leaves. It resembles very 

 closely the clover aphis as found upon apple, but can be distinguished 

 from that insect by its long beak. 



On thorn trees the feeding of this species results in a curling of the 

 leaves which is very conspicuous, the twisted leaves taking on a 

 purplish cast. On quinces, however, it does not curl the leaves, or 

 at least not to such an extent. 



SEASONAL HISTORY. 



The eggs of this insect are laid in the fall upon the twigs of the 

 quince, and the stem-mothers liatch in the earl}' spring. By early 

 summer the insects are abundant and winged forms are being pro- 

 duced. This production of winged forms, or migrants, continues 

 until late summer. The migrants fly from their Avinter hosts to 

 clovers and peas and produce numerous generations on these plants 

 in a manner very similar to that of the clover aphis. In the fall, 

 migrants are produced which return to the quinces and produce the 

 egg-laying females, which after mating with the males deposit the 

 winter eggs. The flight of the insects from clover begins in Septem- 

 ber and extends throughout October. 



PEAR APHIDS ATTACKING THE FOLIAGE. 



Several species of aphids are found upon pear foliage. Most of 

 these, however, occur also upon other trees and are treated elsewhere 



^ Aphis medicaginia Koch. 'Aphis crataegifoUiie Fitch. 



'^ Hyaduphis wylostei (Schrank). 



