CHINCH BUG WEST OF MISSISSIPPI RIVER. 



49 



these cages the living chinch bugs were placed and cheesecloth 

 stretched over the top to prevent their escape. All of the cages were 

 kept on a table in the office, which was heated day and night, and were 

 kept well moistened to promote the rapid development of the fungus. 

 The live chinch bugs which had been dusted with the spores of the 

 fungus were then placed in these cages and the results compared with 

 check cages into which were placed live chinch bugs not previously 

 inoculated. Most of the bugs were provided with plenty of food. 

 Some, however, were placed in a cage containing no food to see if the 

 rate of mortality and appearance of the fungus were to any extent 

 dependent upon the food supply. These experiments are here given, 

 with a record of each cage and its check. 



Experiments with living chinch bugs. 



CAGES CONTAINING PLENTY OF FOOD. 



Cage 

 No. 



J 63 

 a \62 



&! 63 



80 



82 

 83 

 90 

 89 

 93 

 92 

 108 

 108a 



Number 

 bugs 

 used. 



25 

 40 

 15 

 18 

 9 



25 

 33 

 25 

 25 

 25 

 30 

 25 

 25 



Treatment given. 



Inoculated 



Check 



After 14 days transferred from 62a to 63a 



Taken from 62a and inoculated 



Taken from 63a and placed in cage free from 

 fungus. 



Inoculated 



Check 



...do 



...do 



...do 



...do 



...do 



...do 



Number 



Number 



of days 



of bugs 



experiment 



which 



continued. 



died. 



14 



11 



14 







24 



15 



24 



17 



24 







22 



18 



22 



4 



31 



20 



31 



4 



35 



20 



39 



4 



30 



17 



30 



5 



Number 



upon which 



visible 



fungus 



appeared. 



7 

 

 11 

 7 

 



4 

 

 7 

 

 1 

 

 11 

 



CAGES CONTAINING NO FOOD. 



120 



29 

 25 



Inoculated 



18 

 18 



27 

 5 



21 



122 



Check 













The fungus always appeared about the third day after the death of 

 the chinch bug, and in no case did it appear sooner than six days after 

 inoculation, the bugs gradually dying and some remaining alive 35 

 days. Living bugs removed from cage 63, where the bugs were dying 

 and fungus developing, did not die when removed to another cage 

 away from all infection, even though the moisture conditions were 

 about the same. However, all of those remaining in cage 63 died 

 and afterwards became covered with the fungus. This indicates that 

 the rate of mortality can be checked if the bugs are removed from the 

 presence of the fungus. 



As between the inoculation and check cages there was a marked 

 difference observed in the rate of mortality, for which no cause other 

 than Sporotrichum seemed to be responsible, as the death rate was 

 always greatest in the inoculated cages. The greatest mortality and 



