PLANT LICE ATTACKING THE ROOTS 



115 



Fig. 79. 

 Clem. 



-Adult of Crambus luteolellus 

 Slightly enlarged. Original. 



Plant Lice attacking Beet Roots 



In Washington and Oregon sugar beets sometimes are seriously 

 infested by a plant louse (Pemphigus feete Doane). Affected plants 

 fail to make normal growth, 

 look sickly, and the main root 

 grows spongy. The lice cluster 

 on the smaller rootlets. There 

 are several generations in the 

 course of a single season, and 

 occasionally winged individuals 

 appear and fly to other fields. 

 It is probable that the species 

 lives normally on some wild 

 plant, but the identity of this 

 has not been discovered. 



In Colorado another species, Tychea brevicornis Hart., has wrought 

 similar injury. 



No direct means of control is known for either of these pests. 



The Sugar-cane Mealy-bug (Pseiiclococcus calceolarice Mask.) 



In Louisiana the roots, crown, and stalk of sugar cane are attacked 

 by small, degenerate insects which work in clusters made conspicuous by 

 a white, cottony secretion. The insect itself is soft bodied, pink, and 



wingless. Only the males are winged, 

 and they are seldom noticed. 



For the most part they pass the 

 winter on seed cane, but may sur- 

 vive also on Johnson grass. When 

 the seed cane is planted in the 

 spring, the young are transferred 

 with it to the fields. They may 



hibernate also on cane stubble. 

 Fig. 80. -The common, brown ant. .^ ^^^ ^^^^ 



Lasius niger americanus Mayr. i-v^kj^^o,^ kj i 



Enlarged and natural size. Original, move towards eradication, combined 



