1 895.] ENTOMOLOGICAL NEWS. 83 



DEPARTMENT OF ECONOMIC ENTOMOLOGY, 



Edited by Prof. JOHN B. SMITH, Sc. D., New Brunswick, N. J. 



The Chinch-Bug. Bulletin No. 55, from the office of the State Ento- 

 mologist of Illinois, Prof. S. A. Forbes, is an interesting little pamphlet. 

 It contains a very brief record of the chinch-bug invasion of 1894, the 

 prospects for 1895, a brief statement concerning contagious disease and 

 other experiments, and a series of recommendations for 1895. There 

 are only seven pages of print, but they contain a great deal of history and 

 suggestive information. "The history of chinch-bug injury in Illinois is 

 substantially that of a succession of waves of increase which rise to a 

 highest point and then suddenly fall away to insignificance, the rise of 

 the wave usually occupying from three to five years or more, and its re- 

 cession requiring only one or two." Prof. Forbes thinks it probable that 

 the culminating point of such a wave has been reached and would feel no 

 surprise if the season of 1895 witnessed its recession. As an important 

 factor in causing the decrease of the insects he recognizes the "white 

 muscardine" disease, due to Sporatrichum globuliferum, but he is not 

 enthusiastic as to the possibility of controlling chinch-bug injury by the 

 artificial propagation of the disease. Among a series of conclusions the 

 following are especially interesting: 



" i. The white muscardine will not spread among vigorous chinch-bugs 

 in the field in very dry weather to an extent to give this disease any prac- 

 tical value as a means of promptly arresting chinch-bug injury under such 

 conditions. It may be added that chinch-bugs are usually vigorous in 

 dry weather. 



"9. The resistant power of healthy chinch-bugs exposed to infection 

 is well shown by the fact that thousands of bugs, young and old, have 

 commonly lived for many days, and even for several weeks, moulting, 

 maturing, copulating and laying their eggs, when shut up in infection 

 boxes which had been heavily stocked with fungus spores from dead in- 

 sects and had been made in every way as favorable as possible to the 

 development of the disease. The percentage of those that would suc- 

 cumb from day to day was often ridiculously small. 



" From all our experimental work thus far completed, I draw the gen- 

 eral conclusion that infection with the fungus of the white muscardine of 

 the chinch-bug is an uncertain measure, largely dependent for its practical 

 value upon conditions beyond the influence of the experimenter, and 

 whose occurrence or prevalence it is impossible for him to foresee. It 

 appears, on the other hand, to be so powerful an agency for the destruc- 

 tion of chinch-bugs en masse when the weather favors its development 

 and spread, and can be made by proper organization so inexpensive to 

 the individual and to the State, that it is well worthy of the most thor- 

 oughgoing scientific study and practical field experimentation." 



