The chinch bug has been destructive over a considerable area of the state. In its distribution it has occupied the southeastern quarter of the state. With the exception of a few isolated cases and the somewhat more extended patch in Howard and Winneshiek counties, all the damage could be included within a line drawn southwest from Dubuque to Des Moines, and from Des Moines south to the border of the state. Throughout this region there was an extended and severe drouth during the preceding spring and fall, and but little rain, so that the bugs had an opportunity to hibernate under excellent conditions. In many cases wheat and barley were badly injured, and in some cases rye, but in most cases where winter wheat and rye were attacked the grain ripened early enough to avoid serious injury, although the bugs developed in such numbers as to cause great injury to adjacent fields of oats and corn. Throughout this area Osage hedges are a very common feature of the farms. In a great proportion of the reports received it is evident that these, or conditions similar to the presence of hedges, have permitted the hibernation of the bugs, and that in most cases the movement has been directly from such places into the fields of wheat or rye most convenient. It would seldom appear that the bugs traveled any great distance from their place of secretion. A point that is rather interesting is that the bugs have been most injurious in regions where winter wheat and rye have been a common crop for some years past, while in the districts where spring wheat or barley are the principal crops there has been less injury. The inference would see in to be that while winter wheat and rye were not so seriously injured by the bugs they furnished the most favorable conditions for their development in early spring, possibly furnished them winter quarters, and, as a result, other crops in their vicinity are more seriously attacked.
Osborn, Herbert and Mally, C. W.
"Observations on insects---Season of 1894.,"
Bulletin: Vol. 3
, Article 8.
Available at: https://lib.dr.iastate.edu/bulletin/vol3/iss27/8