Tllinois Natural History Survey ~3- Identification Notes 1 
Flea beetles frequently found on corn 
Chaetocnema pulicaria Melshe ~ Corn flea beetle, 
This small black beetle is at most about 1/17 inch in length, and 
is primarily responsible for flea beetle leaf injury to com and for 
transmitting Stewart's disease of corn. It is closely similar to 
confinis, the sweet potato flea beetle, but in pulicaria the antenna 
is dark, the lateral margin of the pronotum is rounded to the anterior 
angle, and the pronotum is extremely finely and closely punctured and 
rather dull in appearancee The corn flea beetle is generally distri- 
buted throughout the corn belt and over the eastern United States. It 
feeds on many species of grasses and sedges, and has been found active 
from April to November. It overwinters as an adulte 
Chaetocnema denticulata Illig. = Toothed flea beetle. 
This flea beetle may be nearly twice the size of the corn flea 
beetle. It is capable of transmitting Stewart's disease but is un- 
important in this rolee Generally it occurs on corn in much smaller 
numbers than the corn flea beetle but appears to prefer several native 
grasses which are hosts also for the corn flea beetle. It is generally 
distributed over the eastern United States. 
Chaetocnema confinis Crotch + Sweetpotato flea beetle 
The sweetpotato flea beetle is of the same size and appearance as 
the corn flea beetle and has been confused with ite Its presence in 
corn fields is doubtless due to the presence of its native hosts which 
are various species of the morning glory family (Convolvulus and Ipomoea). 
It probably causes no injury to corn but it has successfully transmitted 
Stewart's disease under laboratory conditions. It overwinters as an 
