226 



PSYCHE 



[March 1893. 



mined as Empusa aphidis by Ur. 

 Thaxter, and doubtless identical with 

 the Entomophthora of Prof. Forbes's 

 presidential address. 



With this material I was able to test 

 my theory that chinch bugs from the field 

 having been made sick by contact with 

 the dead bodies of bugs killed by dis- 

 ease in the laboratory, if turned loose in 

 the field would communicate the disease 

 to the field bugs. I found that in the lab- 

 oratory exposure of healthy bugs to bugs 

 dead from disease, was invariably fol- 

 lowed by the death of the exposed bugs 

 in from eight to twelve days. A simi- 

 lar operation in the field led to the same 

 result. 



I have thus experimented with all 

 three diseases now known as fatal to 

 chinch bugs : — the Sporotrichum 

 globtdiferum of Spegazzini which I 

 have called the ' ; white fungus" dis- 

 ease : the Empusa aphidis of Hoffman 

 which I have called the "gray fungus" 

 disease ; and the Micrococcus i?zsecto- 

 rutn of Burrill, which is abacterial dis- 

 ease. The Sporotrichum globuliferum 

 (thus determined by Dr. Thaxter) is 

 identical with Botrytis referred to by 

 Prof. Forbes in his address. 



I have been able to keep two of these 

 diseases alive through two successive 

 winters in my laboratory, and have been 

 able to supply farmers with infection 

 upon demand in the following season. 

 My experiments have shown that the 

 two fungus diseases, Sporotrichum and 

 Empusa, are more destructive in damp 

 weather than in dry, while the bacterial 

 disease (Micrococcus) is most destruc- 



tive in hot, dry weather ; thus in 1S90, 

 which was a very dry year in Kansas, 

 the crops being seriously injured by 

 drouth in all parts of the State, the 

 fungus diseases had very little effect in 

 the destruction of the chinch bug, while 

 the bacterial disease was exceedingly 

 destructive. During the year 1S91, 

 which was a wet year in Kansas up to 

 the end of July, the fungus diseases 

 sent out from my laboratory again re" 

 sumed their destructive effect in the 

 fields ; the bacterial disease becoming 

 most destructive after the close of the 

 wet weather in July. 



Considerable prominence having 

 been given to the subject of my experi- 

 ments during the year 1890, the legisla- 

 ture of Kansas in February, 1S91, made 

 a special appropriation of $3,500 to 

 enable me to continue my investigations 

 upon a larger scale than had previously 

 been possible. By means of this ap- 

 propriation I have been able to equip a 

 bacteriological laboratory and obtain 

 the apparatus necessary, for thorough 

 study of the subject. I have also been 

 able to propagate infection upon a large 

 scale, in order to meet the large de- 

 mand from the farmers of Kansas and 

 other States for infected chinch bugs. 



During the year 1S91 infection has 

 been furnished to about 2,000 farmers, 

 chiefly in Kansas, but also including all 

 the western States exposed to the rav- 

 ages of the chinch bug. I have re- 

 ceived 1 ,390 reports from farmers stat- 

 ing the results of their experiments. Of 

 these field experiments 1 ,050 have been 

 successful, 1S7 unsuccessful, and 153 



