70 PAPEES ON CEBEAL AND EOEAGE INSECTS. 



We only know that the higher up the insect punctures the stem the 

 more likely is the attack to result only in the transverse rows of holes 

 across the leaves, as shown in figure 21 at a. In any case tins ridging 

 or hilling up would only form a possible slight protection against the 

 injurious effects of the feeding of the beetles. Once the larvae have 

 started to burrow their way downward in the stem there is no way 

 whereby they can be reached by any measure likely to seriously 

 affect them. The beetles can not be trapped by inducing them to 

 hibernate under piles of rubbish prepared for them especially for this 

 purpose, because there is excellent proof that they pass the winter 

 in fields entirely bare of vegetation. Late planting of the crop, as 

 exemplified by repeated replantings, does not offer any encouragement 

 in the way of preventing future injuries. As shown by the observa- 

 tions of Messrs. Walton and Hyslop, very few of the insects hibernate 

 in the roots or old stalks, so that the pulling up and burning of these, 

 as in destroying the larger corn stalk-borer, would not be of much 

 value against this insect. They probably do not hibernate to any 

 extent in their uncultivated food plants. 



Fortunately, however, the farmer has within his reach two most 

 practical and efficient measures of prevention. One of these is to 

 entirely exterminate from his fields any of the natural food plants of 

 this species. Indeed, he should by no means attempt to raise a crop 

 of corn while any of this natural vegetation, upon which the insect 

 can subsist, is still in existence. The other measure is to follow corn 

 or rice with some crop upon which this insect can not feed and never 

 to plant corn immediately after corn or rice. On the farms of the 

 Messrs. Shannonhouse most convincing illustrations were afforded 

 of almost complete protection by rotation of crops. While in no 

 case was it possible to find a badly infested field of corn foUowing 

 cotton, there were plenty of illustrations of the disastrous effect of 

 attempting to raise corn during successive years on the same ground. 



One field offered such an excellent illustration of this phase of the 

 problem that Mr. William T. Shannonhouse had it photographed, and 

 these photographs are used for illustration in Plates VI to VIII. In 

 1910 the eastern portion of this field had been devoted to cotton, 

 the western portion to corn. In the year 1911 the entire field was 

 planted with corn; as a result that portion on which corn had been 

 raised the previous year (see PI. VI) was almost totally destroyed 

 by this insect, while the other portion, where cotton had been grown 

 (see PI. VII), was almost entirely exempt from attack. In order 

 to show the abruptness with which this injury terminated and the 

 exactness with which this corresponded to the dividing line between 

 the two previous crops, the farmer who had himself cultivated the 

 field in 1910, and was therefore perfectly familiar with it, was induced 

 to stand exactly upon the dividing line between the corn and the 



