58 
BULLETIX 1476, U. S. DEPARTMENT OF AGBICULTUBE 
Table 16 shows that in the 14 fields under observation an average 
of 23.6 per cent of the beet plants were injured and 20.3 per cent of 
the plants actually contained the borer at the time of examination. 
The difference between the percentage of plants showing injury 
and the percentage actually containing the borer at the time of 
Fig. 26. — Beet stems injured by larvae of the European corn borer 
examination is due to the migration of the borers from some of the 
badly injured plants to other plants furnishing a fresher food sup- 
ply. There were on an average 1.69 borers per infested plant. 
In some of the smaller fields and in home gardens representing 
maximum infestation the beet crop was abandoned, owing to the 
injury to the roots and leafstalks. 
