290 



F'RUIT INSECTS 



Fig. 247. — The black 

 peach aphis, adult apterous 

 viviparous female. Enlarged. 

 Redrawn after Miss M. A. 

 Palmer. 



tablish new colonies. In midsummer most of the lice leave the 

 branches and migrate to the roots, but usually a few remain 

 above ground until winter. The full-grown wingless form 



(Fig. 247) is a little less than y^ i^^ch 

 in length, nearly black with portions 

 of the legs yellowish. The winged 

 form is a httle longer and more slen- 

 der; the young resemble the adults, 

 but are lighter in color. 



The greater part of the injury to 

 the trees is caused by the under- 

 ground form, although when very 

 abundant the aerial forms may kill 

 young trees. The injury caused by 

 the root form is often mistaken for 

 peach yellows or attributed to some 

 other cause, as winter injury, poor soil or the use of winter insec- 

 ticides. The trees are stunted, do not put out the proper new 

 growth and the fohage takes on a yellowish sickly appearance. 

 Nursery stock is very Hable to infestation, especially when grown 

 on light sandy soil. The 

 lice remain on the roots at 

 the time of digging and are 

 thus introduced into new 

 orchards. Trees are most 

 susceptible to injury the first 

 and second years after plant- 

 ing. Even if not killed out- 

 right their vitality may be 

 so weakened that they never 



fully recover, but always remain undersized and incapable of 

 bearing full crops of fruit. 

 Treatment. 

 To avoid introducing the pest into new orchards set only 



Fig. 248. — The black peach aphis, 

 winged female. Enlarged. Redrawn 

 after Miss M. A. Palmer. 



