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 
Fic. 283.—The Woolly Apple Fic. 2S4.—Scars on twigs caused by 
Aphis. Clusterof lice on twig. work of the Woolly Apple Aphis. 
Original. Original. 
cent kerosene emulsion may be used instead of the tobacco dust, 
drawing away the dirt and applying 2 or 3 gallons. 
The Grape-phylloxera (Phyllorera vastatrix Planch.) 
Numerous small, rather spherical galls are formed on the under 
surface of the leaves of grapes, while on the roots other colonies of the 
