40 
BULLETIN 1476, U. S. DEPARTMENT OF AGRICULTURE 
Fig. 20. — European corn-borer larvae at base of barnyard-grass stubble 
Table 4. — Character of injury to flowering plants by Pyrausta nubilalis larvae 
(New England, 1918 to 1922) 
Name of 
plant 
Parts of plant attacked 
Appearance of infested 
plants 
Remarks 
Dahlia- 
China aster. 
Chrysanthe- 
mum. 
Zinnia. 
Calendula. 
Canna 
Cosmos 
Salvia 
Geranium . 
Hollyhock. 
Gladiolus- 
Oolden glow.. 
Stalks, flower stems, 
and flowers. Eggs 
freely deposited on 
leaves. Small larvae 
feed thereon. 
Stalks and flowers. 
Eggs rarely deposited 
on leaves. 
Stalks, flower stems, 
and flowers. Feeding 
areas on leaves but no 
eggs found. 
Stalks, flower stems, 
and flowers. Eggs 
rarely deposited on 
leaves. 
Stalks, flowers 
Large masses of light- 
yellow frass extrude 
from larval tunnels. 
Affected plants wilt and 
and break over when 
severely injured. 
Same as above. Most of 
injury to middle part of 
stalk. Affected stalks 
usually break over. 
do 
.do. 
.do. 
Stalks, midrib of leaves 
and flowers. Feeding 
areas on leaves but no 
eggs found. 
S talks. Rarely in flower 
stems. 
Stalks, flower stems. 
Stalks 
Stalks, leaf stems 
Light-brown frass ex- 
trudes from larval tun- 
nels. Most of injury to 
midrib of leaf. 
Large masses of light-yel- 
low frass extrude from 
larval tunnels. Affected 
parts break over when 
severely injured. 
do 
do 
do 
Stalks and flowers. 
Eggs occasionally de- 
. posited on leaves. 
Small larvae feed 
thereon. 
Stalks, flower stems. 
Eggs rarely deposited 
on leaves. 
.do. 
.do. 
Most susceptible of the flowering 
plants. Injury most severe at 
time of blooming. Entire plant- 
ing frequently infested. Roots 
(tubers) not infested. 
Frequently infested in field and in 
greenhouse. Production of 
blooms usually reduced or pre- 
vented entirely. 
Greenhouse and hardy varieties 
very susceptible. Size of blooms 
not affected by slight or late in- 
jury to stalks. Blooms reduced 
in size or prevented entirely by 
early breaking over of the stalk. 
Same as above except not found 
infested in greenhouse. Rarely 
grown under glass. 
Same as above. Rarely found in- 
fested in greenhouse. 
Seldom infested except when grow- 
ing near other infested plants. 
No infestation found in roots. 
Most of injury to main stalks, late 
in season. Flower buds seldom 
open on part of plant broken 
over. Not found infested in 
greenhouse. 
Do. 
Do. 
Same as above. Leaf stems of 
youne plants particularly sus- 
ceptible. 
Weakened or broken stems often 
render the spike unmarketable. 
Slight injury to flower stems, no 
appreciable effect on spike. Not 
infested in greenhouse. 
Most of injury occurs late in season 
after flowers have formed. No 
appreciable injury to plant. 
