202 



APPLIED ENTOMOLOGY 



own. This process continues through the summer but in the fall the young 

 desert the leaves (Fig. 194) and work down to the roots and rest until the follow- 



Fia. 194. Grape Phylloxera: a, galls on grape roots; 6, galls enlarged, showing the 

 insects; c, Phylloxera from a root gall: 6 and c enlarged. (From Sanderson, Insects Injuri- 

 ous to Farm, Garden and Orchard; after Marlatt, U. S. D. A.) 



FIG. 195. Grape root showing galls caused by Phylloxera. (From Berlese.) 



ing spring. Then they attack the roots, forming swellings (Fig. 195) which on 

 young rootlets stop their growth, and on the larger ones cause decay which spreads 

 around the root and kills it beyond that point. 



