New Yoek Agricultural, Experiment Station. 415 



PLANT LICE.^ 



Several species of plant lice attack the apple, but the most 

 common in this State is the apple-tree aphis, Aphis mali Tab. 

 This is the little, green louse that attacks the buds and leaves in 

 the spring. It often occurs in great numbers on the under side of 

 the leaves, sucking the sap from the tissues. This irritation causes 

 the leaves to curl, thus affording partial protection to the insects. 

 The winter is passed in the egg stage. Many generations and 

 countless individuals, both winged and wingless, are produced 

 during the summer. They secrete a clear liquid (honey dew) 

 which sticks to the leaves and twigs and finally turns black, because 

 of a black fungus which grows in it. 



Treatment. — The trees should be carefully watched, and, when 

 the lice first appear, sprayed thoroughly with a solution of whale 

 oil soap and water — one pound to seven gallons. The lice may 

 appear any time after the buds burst. It is important to give the 

 infested trees at least one or, as is often necessary, two thorough 

 applications before the leaves have become curled. It will be very 

 difficult to reach the lice when they are protected by the curled 

 leaves. The spray should be directed toward the under side of 

 the leaves. 



INSECTS ATTACKING TRUNK AND BRANCHES. 

 THE WOOLLY LOUSE OF THE APPLE. 



{Schizoneura lanigera Hausm.) 



This insect is easily detected by the white wool-like substance 

 which the lice secrete and which clings to their bodies. They 

 attack both the roots and young branches causing gall-like swell- 

 ings. They are especially injurious to young trees and sometimes 

 do serious injury to new grafts. 



Treatment. — When occurring upon the roots considerable 

 relief will usually result from the application of finely ground 



8 For a further discussion of plant lice, see Bulletin 139 of this Station, by 

 V. H. Lowe. 



