442 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



soils and the pest rarely becomes very troublesome on heavier 

 soils. Injury is also more or less periodic, the aphides almost 

 disappearing after doing serious injury for two or three years. 

 Fortunately the strawberry is the only food plant and the root- 

 lice found on other crops are entirely different species. 



Life History. During the winter the small, shining black 

 eggs may be found thickly clustered upon the stems and along 



FIG. 316. Strawberry root-lice clustered on small rootlets from crown of 

 plant greatly enlarged. 



the midribs of the green leaves. They are mere specks, one- 

 thirty-fifth inch long and oval in shape. In early winter as many 

 as sixty-five have been found on one leaf, but many fall off and 

 are destroyed before spring. The eggs hatch early in April in 

 Delaware, the exact time depending on the season. The young 

 aphides feed a little on the leaves bearing the eggs but soon find 

 their way to the tender young leaves of the crown. These 



