studies in Artificial Cultures of Entomogenous 



Fungi. 



Most insects are subject to contagious diseases which determine to 

 some degree the extent of the ravages of injurious species and 

 wliich, at times, destroy beneficial ones. The possibility of con- 

 trolling these diseases, and of introducing epidemics where they are 

 desirable, has led several investigators to carry on researches in 

 this direction ; and the results of some of these investigations have 

 led their authors to believe them of considerable economic im- 

 portance. 



The subject has become one of general interest, and it is desirable 

 to have as complete a knowledge as possible of the affinities and life 

 histories of such entomogenous fungi as are capable of artificial cul- 

 tivation. The object of the present paper is to determine by means 

 of artificial cultures, the life histories and the relationship of the 

 forms studied as well as to carry on preliminary studies respecting 

 the practicability of introducing diseases among insects. Most of 

 the forms studied are members of the genus Isaria^ and its perfect 

 form Cordyceps ; the others are species of the genus Sporotrichum. 



The material from which the present study was made has been 

 obtained from specimens collected in the vicinity of Ithaca, ]^. Y., 

 or kindl}' sent by others. The studies in artificial media were 

 made in the labratory of cryptogamic botany in Cornell University 

 under the supervision of Professor G. F. Atkinson. The experi- 

 ments in the infection of insects were carried on in the insectary of 

 the Cornell Agricultural Experiment Station under the super- 

 vision of Professor J. H. Comstock. 



When a study with artificial cultures is to be made, the first step 

 is to separate the disease-producing organism from the accompany- 

 ing bacteria and fungi, and to grow it in pure cultures. To do this, 

 plate cultures are made with nutrient agar or some like preparation. 

 In the present work, nutrient agar, the ordinary agar-agar-peptone- 



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