THE DESERT CORN FLEA-BEETLE. 6 
these crops follow one another year after year, and the area becomes 
established and known as a farming region, the insects develop in 
still larger numbers, being fostered by abundant food and protected 
by certain careless methods of farming. Sooner or later we have an 
economic pest of grave importance. 
The injury caused by the flea-beetle under discussion is due to 
just such circumstances, and to these alone. 
As has been suggested previously in this paper, this insect does 
its greatest injury to Indian corn of various kinds and to the non- 
saccharine sorghums, while it bids fair to be a very important pest 
of Sudan grass. It also exerts a minor influence upon all crops on 
which it feeds, taking its yearly toll from each of them. 
NATURE OF INJURY. 
In destroying its food plant, this beetle works from both ends, as 
it were, the adults attacking the plant above the ground and the 
larvae below the ground. The adults eat out the chlorophyll of the 
leaves, and when sufficiently numerous they cause the leaves to 
wilt. If feeding is long continued, new growing plants will be killed. 
As the eggs are deposited below the surface of the ground, the larvae 
immediately begin feeding upon the roots, and soon the plant has 
quite a shallow root system that will not support it in a thrifty 
manner. 
The roots, after having been injured by the larvae, attempt to 
overcome this injury by sending out new laterals, as illustrated in 
figure 6, page 11, and then sometimes slight windstorms will cause 
plants to blow over and lodge badly, thus further reducing the yield. 
EXTENT OF INJURY. 
The extent of damage inflicted in any year upon any particular 
crop depends largely upon conditions. First, if corn is planted 
early in the spring, it will usually suffer most heavily. Then again, 
if the grain is planted under conditions which have been ideal for 
the hibernation of adult beetles, the damage will also be considerable. 
In the early months of the year sweet corn is especially liable to 
attack, and partly because of this it is almost impossible to secure 
roasting ears early. 
Mr. Peterson, of the Bureau of Plant Industry, who was formerly 
in charge of the experiment station located at Bard, CaL, states that 
these beetles damage corn on the station plats to a considerable 
extent, and that they have caused this damage there for several years. 
The writer has seen small pieces of corn completely destroyed by this 
beetle, the attack occurring just as the corn was coming through the 
ground. In these cases the owner often thought that the corn had 
failed to come up. 
