PLANT LICE INJURING THE ROOTS 



227 



or 5 inches, sprinkle 2 to 6 pounds of tobacco dust on the roots 

 and soil thus exposed, and then replace the dirt removed. Ten per 



Fig. 283.— The Woolly Apple 

 Aphis. Cluster of Uceontwig. 

 Original. 



Fig. 284. — Scars on twigs caused by- 

 work of the Woolly Apple Aphis. 

 Original. 



cent kerosene emulsion may be used instead of the tobacco dust, 

 chawing away the dirt and applying 2 or 3 gallons. 



The Grape-phylloxera {Phylloxera vastatrix Planch.) 

 Numerous small, rather spherical galls are formed on the under 

 surface of the leaves of grapes, wliile on the roots other colonies of the 



