5 



INFLUENCE OF EXCESSIVE DROUTH. 



The general conditions precedent to this chinch-bug uprising 

 conform to the established principle that a succession of dry and 

 warm summers has most to do with the origin of a chinch-bug 

 outbreak; but it has not been heretofore noticed that drouth may 

 become too severe for even this drouth-loving species. In some 

 parts of Washington county the corn crop, and even the field 

 grasses infested by the chinch bug, had been almost completely 

 destroyed, in 1886, as early as the beginning of Au2:ust, thousands 

 of acres standing at the time as dry as in midwinter. This coming 

 at the breeding season of the second generation, their multiplica- 

 tion was cut short, large numbers of the young perished in the 

 fields, and the old, no longer able" to find food there or to mature 

 their eggs, were driven in immense numbers to the woods. 



A visit made to this region at harvest time in 1887 showed that 

 many fields at a little distance from the woods contained scarcely 

 a chinch bug where there had been myriads the season before; and 

 that fields in which these pests occurred in numbers sufficient to do 

 serious mischief were almost invariably beside woodlands, or, if at 

 a little distance, that only the borders nearest the woods were 

 suffering. In the western part of the adjacent county of Clinton 

 (visited at the same time), where the corn had been much less 

 completely killed the year iDefore, the chinch bugs were scattered 

 everywhere, even miles from woods, and the early damage to small 

 grain was much more severe. 



EFFECT OF ABANDONING CORN AS A CROP. 



These facts give us a hint of the results possible in a small 

 grain country, if corn be abandoned for a time to reduce the food 

 supply of the second generation. They amount, in fact, to a nat- 

 ural experiment on a very large scale, with this procedure. The 

 results were certainly interesting; but the method has this draw- 

 back, that the meadows and pastures may be thus exposed to 

 damage by desperate and starving hordes of chinch bugs searching 

 the country for food. No serious injury was done, however, in 

 this way to grass lands in the district indicated. While we shall 

 see later that meadows may be used freely and extensively by the 

 chinch bug as breeding grounds in spring, this is usually only 

 where a fresh and succulent growth of young grass offers an ex- 

 '\ traordinary temptation. It would seem that the abandonment of corn 

 wherever small grain is largely raised may be at least as effective a 

 preventive measure as the abandonment of wheat where corn is 

 the principal crop. Indeed, it may well be more so, since the 

 attempt to reduce the first brood by limiting wheat culture must 

 be made during the season of active growth for nearly every sort 

 of vegetation, the chinch bugs having, therefore, at worst, an 

 abundance of every kind of food save wheat; but the second brood 



