99 



assistants, Flint and Smith, near Coulterville, in Randolph county, 

 at several times between December 19, 1911, and March 20, 1912. By 

 selecting the most favorable times and places more than half of the 

 bugs were disposed of, as was ascertained by carefully collecting and 

 counting all the chinch-bugs in several bunches of grass, or on meas- 

 ured surfaces of other shelter, both before and after the field was 

 burned over. One of the most definite tests of this description was 

 made March 19 and 20, 1912, by counting the bugs in twenty stools 

 of bunch-grass — ten before and ten after the field was burned. In this 

 field the ten unburned bunches contained 5198 living and 335 dead 

 chinch-bugs, and the ten burned bunches contained 2767 living bugs 

 and 767 dead. If we may assume that the number of living insects 

 was practically the same in these two lots of bunches before the burn- 

 ing, then 47 percent of the chinch-bugs (2431) were destroyed in the 

 lot burned over, 432 of these being merely killed and the remainder 

 burned up. In the whole series of this year's experiments with bunch- 

 grass, the chinch-bugs in 46 unburned and 40 burned stools of these 

 plants were counted in all, with the result that the unburned stools 

 averaged 554 and the burned stools 280 living chinch-bugs each. 

 According to these data about half the bugs had been killed by burn- 

 ing the grass. 



Furthermore,according to counts made of measured areas, each a 

 foot in diameter, covered with leaves, weeds, and other similar rub- 

 bish, (Fig. 4) twenty-five such patches yielded, unburned, 12,456 

 chinch-bugs (498 to the patch), and eight others yielded 121 chinch- 

 bugs each after they had been burned off. This would indicate the 

 destruction of 76 percent of the bugs under such shelter by the opera- 

 tion. In brief, from 50 to 75 percent of the chinch-bugs contained in 

 these winter shelters seem to have been destroyed by our experimental 

 burnings under these peculiarly favorable conditions — sufficient evi- 

 dence of the utility of this method when such conditions are general 

 and continuous rather than local and temporary. Southern Illinois 

 lends itself, however, rather poorly to the burning-out method, an 

 abundance of shelter for hibernating insects being afforded in thick- 

 ets, woodland borders, hedges, and other miscellaneous places of winter 

 resort which it would be quite impossible to burn over at all gener- 

 ally. Nevertheless, both our own experience and the successful work 

 of others show the very great value of this method whenever and 

 wherever conditions favor its use. It is the least expensive of all 

 operations against the chinch-bug, and should be undertaken when- 

 ever possible by cooperative, neighborhood measures, both in one's 

 own interest and in that of the community at large. 



Destruction of Chinch-bugs at the Wheat Harvest 



The best means known in 1909 for preventing the escape of chinch- 

 bugs from an infested field of wheat at harvest-time was to pour a 



