304 ILLINOIS ACADEMY OF SCIENCE 



scarcely have failed to notice dead bodies of house flies 

 in Autumn sticking to window panes and to other sur- 

 faces, with the abdomen whitened by the spores and spore 

 producing bodies of this fungus, and often with a broad 

 circle of the discharged spores adhering to the sur- 

 rounding surface so as to form a sort of halo about the 

 dead insect. Other species of Empusa attack grasshop- 

 pers and plant lice, as well as many other kinds of in- 

 sects, and epidemics of another fungus disease, Sporo- 

 tricJium glohuliferum, have often contributed materially 

 to the suppression of the chinch bug during outbreaks 

 of that notorious pest. It would be exceedingly difficult 

 to grow citrus fruits profitably if the scale insects which 

 attack these fruits were not largely destroyed and thus 

 held in check by fungus diseases. Indeed, one of the 

 authors has himself observed a mortality of 95 per cent 

 in the scale insect, Aspidiotiis ancylus, on pecans in 

 Georgia, due entirely to fungus disease. 



The fact that fungus diseases at times cause the de- 

 struction of great numbers of insects has aroused much 

 popular as well as scientific interest ; and since many of 

 these fungi may easily be cultivated in the laboratory 

 on non-living culture media, the question whether arti- 

 ficially produced epidemics of such diseases might not 

 afford a ready means for controlling outbreaks of in- 

 jurious insects has received much serious attention. The 

 idea of employing their fungus diseases to control the 

 ravages of noxious pests is not a new one. DeBary, 

 the Tulasne brothers and others, as early as the middle 

 of the last century, called attention to the important 

 natural check on destructive insects afforded by the 

 ''white muscardine", Isaria densa Link., and similar 

 organisms, and since that time many workers have at- 

 tempted to produce epidemics of such diseases by arti- 

 ficial means for the purpose of combating insect pests. 



Among the host of investigators who have worked on 

 this general problem, Krassilschik (1884) employed the 

 so-called ''green muscardine", Metarliisium anisopliae 

 Metch., to combat the beet weevil, Cleonus punctiventris 

 Germ. ; Eorer (1910) employed the same fungus in Trini- 



