Fourth Annual Report. 13 



the ordinary method of infecting with diseased bugs was employed, did not 

 show a greater mortality among the bugs introduced than the artificial cul- 

 ture experiments. The experiments could not be repeated on account of 

 the lack of bugs at that season, so the results were not confirmed. 



8. — Experiments in Spraying. 



In March, 1895, chinch bugs were found in considerable numbers in sev- 

 eral localities, hibernating under stones, pieces of wood, and the like, in the 

 vicinity of cornfields. They were especially numerous in places where the 

 stones, etc., lay on grass or stubble, so that there was a dry shelter between 

 the stones and the ground. Bugs found in these places were sprayed with 

 water mixed with Sporotrichum spores grown on squash; others were 

 sprinkled with dry spores in the same manner. A week later it was found 

 that many bugs in the places infected were dead and covered with Sporo- 

 trichum, while no trace of fungus -covered bugs could be found in places not 

 infected. This experiment suggests the possibility of infecting bugs before 

 they leave their winter quarters. The method of scattering the spores of 

 the disease in a fine spray of water, which appears to be successful in the 

 above experiment, may prove to.be a much more efficient means of spread- 

 ing the infection than we have yet employed. 



The results thus obtained in the field are sustained by the following lab- 

 oratory experiments : 



On March 19, 1895, chinch bugs, found hibernating under the shelter of 

 stones and grass in the vicinity of fields infested by them the previous sea- 

 son were put in flower pots containing moist earth, about 50 bugs in each 

 pot. The bugs in pot 1 were sprayed with distilled water ; in pot 2 with 

 distilled water containing the spores from the squash culture shown in plate 

 I; in pot 3, with spores from the squash culture shown in plate I which 

 had been in a 5 per cent, solution of grape sugar for 24 hours and had com- 

 menced to sprout; to pot 4 were added a few Sporotrichum bugs which had 

 been kept over from the previous year. Although a few white-fungus-cov- 

 ered bugs appeared in the check lot of pot 1, a greater number appeared in 

 pot 2 where Sporotrichum spores were sprayed in distilled water, and still a 

 much greater number in pot 3 where the spores had been sprouted in a 

 sugar solution and then sprayed, and both of the artificial cultures of pots 

 2 and 3 gave better results than were obtained in pot 4, where Sporotrichum 

 growing on chinch bugs was used for infection. We do not look upon this 

 single experiment as at all conclusive, and have others in progress at the 

 present writing. If the method of spreading the infection by spraying 

 proves successful in the field, and particularly by the spraying of sprouting 

 spor-" ' ,o possible that the infection may prove successful even in dry 

 weather. If the bugs in the held are thoroughly sprayed with the sprout- 

 ing spores in the evening, it is possible that the fungus, aided by the mois- 



