PROGRESS REPORT ON THE EUROPEAN CORN BORER 
39 
FLOWERING PLANTS 
Although a large number of flowering plants are known to be 
attacked by P. nubilalis (Table 1), the most important of this 
group, considering their susceptibility and economic importance, 
are dahlia, China aster, chrysanthemum, zinnia, calendula, canna, 
cosmos, geranium, gladiolus (fig. 19), golden glow, hollyhock, and 
salvia. A* summary of the more important observations relating to 
these plants is included in Table 4. With the exception of cosmos 
and dahlia, which 
were slightly infested 
in the experimental 
plat at Silver Creek, 
N. Y., all of these 
observations are lim- 
ited to the New Eng- 
land area. 
WEEDS 
The character of 
the injury to the 
weeds and wild 
grasses which are at- 
tacked by the Euro- 
pean corn borer 
(Table 1) is essen- 
tially the same as has 
been described for 
corn and other eco- 
nomic hosts of the 
insect. Eggs are de- 
posited upon some of 
these weeds and wild 
grasses, particularly 
in the New England 
area, and the result- 
ing larvae may com- 
plete their develop- 
ment and pupate 
within, or may migrate to various other host plants in the vicinity. 
In addition, these plants 'frequently are infested by larvae migrating 
from near-by crops, notably corn. The injury to weeds and wild 
grasses is characterized by the collapse and breaking over of the stems 
or stalks which are severely infested. In weed infestation, such as 
occurs in barnyard grass, the larvae tunnel through the stalks and 
stems, even including the base of the stalk, or stubble, to a point 
below the surface of the ground. (Fig. 20.) The percentages of 
infestation in some of the more susceptible weed hosts are shown 
in Table 20. 
Fig. 19. — Gladiolus stem, showing European corn-borer in- 
festation 
