WOOLLY APHIS 



77 



tation in proximity to the apple trees, but proper spraying for 

 other insects would be of some service in checking attacks. Clean 

 cultivation of the orchard is one of the best preventives. 



The Fruit Bark Beetle (Scolytus rugulosus Ratz). (Fig. 97.) 

 See chapter on Plum, Peach and Cherry Insects, page 113. 



The Woolly Louse or Woolly 

 Aphis (Schizoneura lanigera 

 Hausmann). Bluish - white, 

 flocculent, or cottony patches, 

 wrapping clusters of the lice, 

 are noted on the lower part of 

 trunks or on branches of young 

 trees (Fig. 98), particularly 

 abundant on water - sprouts. 

 There is a root form, also, 

 which is more injurious (Fig. 

 99) . This insect causes gall-like 

 swellings in cracks of which it 

 lives in clusters. A winged 

 form also occurs during the 

 season. The wingless lice are 

 one-tenth inch long; reddish- 

 brown, covered with character- 

 istic cottony or waxy secretion. 



Life History. The woolly 

 aphis lives over winter on the 

 trunks and branches when the 

 season is not too severe. The 

 exact length of life of the adult 

 is not known. Females give 

 birth to living young for an 

 indefinite period. The larvae, 

 when first born, have not the white secretion which soon appears 

 when they begin to feed. 



Injury. As a result of the work of this pest, the bark becomes 

 deeply pitted, or large cavities are formed. The tree ceases to 

 grow at the point of attack. On roots it produces gall-like swell- 

 ings. If abundant, the tree loses its vitality on account of the loss 

 of sap, coupled, perhaps, by transmission of a poison by the insect. 

 This insect is likely to be extremely abundant on any injured por- 

 tion of the tree. 



FIG. 99. Woolly aphis, root form: a, 

 deformed root; 6, root covered with aphids; 

 c.rootlouse, female, much enlarged. (Marlatt, 

 U. S. Bu. Ent.) 



