I 



THE DESERT CORN" FLEA-BEETLE. 3 



these crops follow one another year after year, and the area becomes 

 estabUshed 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 gi*ass. It also exerts a minor influence upon aU 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 

 larvge 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 wiUbe killed. 

 As the eggs are deposited below the surface of the ground, the larvaa 

 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 wiU 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 th(! grain is planted under conditions which have been ideal for 

 the hibernation of adult beetles, the damage wiU 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 cars early. 



Mr. Peterson, of the Bureau of Plant Industry, who was formerly 

 in charge of the experiment station located at Bard, Cal., states tliat 

 these beetles damage com on the station plats to a considerable 

 extent, and that th(;y have caused this damage there for several years. 

 The writer has seen small pieces of com completely destroyed by this 

 beetle, the attack occumng just as the com was comhig thi-ough th(^ 

 ground. In these cases the owner often thought that the com had 

 failed to come up. 



