PLANT LICE ATTACKING THE ROOTS 115 
Plant Lice attacking Beet Roots 
In Washington and Oregon sugar beets sometimes are seriously 
infested by a plant louse (Pemphigus betw 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 
Fie. 79.— Adult of Crambus luteolellus 
Clem. Slightly enlarged. Original. 
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 cither of these pests. 
The Sugar-cane Mealy-bug (Pscudococcus calceolariw 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, eottony 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 
an the seed cane is planted in the 
spring, the young are transferred 
with it to the fields. They may 
hibernate also on cane stubble. 
Fic. 80. — The common, brown ant, 
Lasius niger americanus Mayr. Rotation of crops 1s the first 
Enlarged and naturalsize. Originel. move towards eradication, combined 
