BTLLETIX 427, U. S. DEPARTMENT OF AGRICULTURE. 
In large fields near the one mentioned above larv?e could be found 
in most of the plants, but apparently the vigor of the plants was not 
noticeably affected and the amount of damage done, if any, was 
certainly small. Taking all things into consideration, the damage 
done by the tuber moth to the growing plant in southern California 
is slight in comparison to that caused to tubers. 
The tuber-feeding larva injures the potatoes themselves by tunneling 
through them, so fining these tunnels with excrement and fungus that 
the potatoes, even if not severely injured, are very unsightly and of 
small market value. The character of the injury (figs. 3-5) does not 
seem to be influenced by the condition of the tuber or climatic conch- 
BEJ^B 
Fig. 3.— Potato sliced to show advanced injury by potato tuber-moth larvae. (Original.) 
tion, some larva? digging subepidermal channels while others tunnel 
directly through the substance of the tuber. The loss consists not 
only of the actual substance of the tuber which is channeled and 
ruined, but is also due to the fact that badly injured tubers are 
imsishtlv and undesirable for food. 
ECONOMIC IMPORTANCE. 
Since the first report of the tuber moth, large losses have been 
reported from various sections of the world. Analysis of these reports 
shows beyond a doubt that in mild, dry climates the tuber moth 
works very serious injury to stored potatoes. In similar climates, 
