March 1892. J 



PS r CHE. 



231 



been unable, then, to attempt the in- 

 oculation of chinch bugs with pure cul- 

 tures of Empusa. That the fungus has 

 power to rapidly spread from one bug 

 to another the experiments in our infec- 

 tion cases have clearly shown. 



A chinch bug covered with Empusa 

 seems to be studded with minute gray 

 beads. A thin section cut through the 

 body of a bug in this condition shows 

 the body cavity to be crowded with the 

 mycelial growth and protruding through 

 the integument are vast numbers of 

 broad conidiophores each bearing a 

 single conidium. 



It is by the sudden rupture of the 

 conidiophore due to turgescence that 

 the conidia are thrown to some distance. 



Where the fungus continues its growth 

 to the complete destruction of the chinch 

 bug the whole mycelial mass breaks up 

 into bodies varying from 16 X 29 mi- 

 cromillimeters to 23.5 X 27.4 micro- 

 millimeters. 



In one instance resting spores, appar- 

 ently, were found. These were round 

 bodies with granular contents and thick 

 walls and varying in diameter from 21 

 to 25 micromillimeters. 



A chinch bug that died of Empusa 

 about the middle of July was confined 

 in a moist atmosphere on a sterilized 

 plate October 10 and on Oct. 13 the 

 entire body was thickly covered with a 

 new growth of Empusa. It seems then 

 that the entire mass of this fungus may 

 break up into a resting condition and 

 be capable, whenever the atmospheric 

 conditions will permit, of springing in 

 to new growth. 



Careful experiments will be made in 

 our laboratory this winter to test the 

 capabilities of germination and duration 

 of vitality of the spores and hyphal 

 bodies of Sporotrichum and Empusa. 



I append the following as samples of 

 the reports received from the farm- 

 ers. 



ALFRED DOIDGE, SOLOMON CITY, DICKINSON 

 CO., KANSAS. 



Infection sent May 8. Experiment suc- 

 cessful as reported July 27. 



"I experimented with the infected chinch 

 bugs you sent me last May. They were the 

 first bugs you sent out, and it was very wet 

 weather. After I infected them I turned 

 them out in a twenty acre field of wheat. 

 The bugs were very numerous at that time, 

 ard hatching. The old ones soon began to 

 die and the ground was white with them. 

 Very shortly after there were no old bugs 

 left in the field, but the wheat was red with 

 young ones. It did not seem to take hold 

 upon them. After cutting the wheat they 

 went into five acres of oats. I concluded 

 that it would not pay to harvest the oats. 

 They were black and red from top to bottom. 

 I never saw the like before. About one 

 week from then I went into the oats and to- 

 my surprise the ground was white with dead' 

 bugs and the others were sluggish. In eight 

 inches square I believe I could have picked 

 up 1000 dead bugs. They were all in 

 bunches. My five acres of oats were saved 

 by using the infection. I do not think I lost 

 two bushels in the whole crop. I find that 

 the infection is a success in all that you 

 claim for it." 



Under November date reported as follows : 



"The infected bugs saved me fifty bushels 

 of wheat, four hundred bushels of corn, and 

 two hundred bushels of oats." 



