22 



These facts show the indisposition of the average farmer to 

 modify his practice until his losses are enormous and even ruin- 

 ous ("complete" or "nearly complete" by our reports), — to take 

 measures of prevention, in short, or to apply even remedial meas- 

 ures until his case is desperate, and probably beyond the reach of 

 aid. They also show that he lessens his wheat acreage when that 

 crop is heavily damaged by chinch bugs, because wheat becomes 

 unprofitable, but will do so little, if at all, as a consequence of 

 injury to corn. From the fact that the regions where the wheat 

 area had been largely reduced in 1887 were still regions of great- 

 est injury to small ^'ain and even to corn, we may, perhaps, also 

 infer that this diminution of the wheat area under the circum- 

 stances of extreme destruction there prevailing, had been without 

 good effect. 



A reduction — not abandonment — of the corn area has been 

 sometimes recommended as a measure calculated to restrict the 

 multiplication of the chinch bug by limiting the amount of food 

 for the second generation;* but the results of the comparison of 

 the corn areas of 1886 with the different grades of injury to small 

 strain the following year, are unfavorable to this idea. In South- 

 ern Illinois, for example, the corn areas corresponding to the ex- 

 cessive grades of injury to small grain are respectively 2,572, 2,583, 

 2,767, 2,554, 2,881, 2,971 and 2,648— a variable but ascending series. 

 In Central Illinois, figures corresponding to the first four grades 

 of damage — the only one available— are 6,067, 5,332, 4,587 and 

 4,285 — a rapidly declining series. The figures for Northern Illinois 

 are without especial significance; and those for the whole State 

 show a nearly uniform decline from 4,949 acres, where no injury 

 was done to small grain, to 2,648, where the destruction was 

 complete, — this series thus running in the direction opposite to that 

 which the supposition above mentioned would require. We con- 

 clude, consequently, that any reduction of the corn acreage, to be 

 an effective remedy for chinch-bug injuries, must, at any rate, go 

 far below the area actually raised in any of the groups of town- 

 ships represented on our tables. 



INJURY TO ALL CROPS COMBINED, COMPARED WITH AVERAGE OF EACH. 



To summarize my data more compactly I have attempted to 

 unite the estimates of damage to all the crops injured by the 

 chinch bugs so that the sum of the losses to agriculture due to 

 this si)ecies may be treated as a single quantity. This I could 

 only do by regarding small grain, grass, and corn as of equal im- 

 portance, numbering the grades of injury recognized from 0 to 7, 

 adding together for ea^^h township card the three numbers of the 

 gra(l(\s of injury reported for the three principal crops, and con-j 

 sidering their sum as the total injury for the corresponding townJ 



H(»o Hummary of ciirn«nt opinio i, p. 



