INSECTS AFFECTING PARK AND WOODLAND TREES 6oi 



Birch aphid 



Calliptcrus betulaecolens Mon. 



A delicate yellowish plant louse is sometimes exceedingly abundant in midsummer 

 on the underside of birch foliage. 



This little species is sometimes very injurious to birches in the vicinity 

 of Albany, particularly the ornamental cut-leaved variety, and it is occa- 

 sionally quite destructive in other portions of the State, complaints of its 

 depredations having been received from Herkimer county and also in the 

 vicinity of Buffalo. There is no method of keeping it in check aside from 

 spraying with contact insecticides such as a whale oil soap solution or 

 kerosene emulsion and ordinarily that is impractical. The pest, when 

 abundant, is fed on to a considerable extent by adults and larvae of the 

 two-spotted lady beetle, Adalia bi punctata Linn. 



Woolly beech leaf aphis 



Phyllaphis fagi Linn. 



Cottony masses occurring on the underside of purple beech leaves usually shelter 

 groups of this plant louse. 



This species is a common one on purple beech in parks, and sometimes 

 becomes so abundant as to cover a large proportion of the under surface 

 of the leaves and at such times it ma)' cause considerable injur)- to the tree. 



Description and habits. This aphid is shown clustered on the under- 

 side of leaves and along the mid ribs and smaller veins on plate i i, figures 

 10, ii. The adult females may be recognized by the conspicuous cottony 

 tufts largely concealing the body. The young are pale greenish yellow and 

 may frequently be seen nestling among the hairs so abundant along the leaf 

 veins. The cast skins or exuviae are snow-white, sometimes abundant and 

 may then give a whitish appearance to the underside of the foliage. The 

 partly grown plant louse has the habit of resting with its head close to a 

 vein, from which it is apparently drawing nourishment. The extremity of 

 the young is usually ornamented by a few scattering bluish, white fibers. 



