FOURTH ANNUAL REPORT. 43 



be maintained ; and by multiplying centers of epidemic, one will simply aid 

 nature to spread the disease rapidly and to render it more intense. 



In addition to the results achieved in America, the work and experiments 

 of the Russian scientists, Metchnikoff and Krassilstchik, have shown that 

 it is possible to find on insects invading fields in great numbers parasitic 

 fungi which destroy them, and that these fungi can be cultivated on artificial 

 nutritive media, and, so to speak, manufactured as an article of commerce. 



The numerous trials of the infection of white grubs made in France in 

 the last four years have shown incontestibly that, in the struggle with the 

 underground insects, the processes of Messrs. Krassilstchik and Snow can 

 never give appreciable results. An insect like the chinch bug runs around 

 actively, comes in contact with others, and the spores are quickly dissemi- 

 nated. On the other hand, the white grub, being isolated in the soil and 

 slow of motion, and the muscardine being of comparatively slow growth, 

 the methods applicable to the treatment for the chinch bug cannot be ap- 

 plied here. 



Insects living on or above the surface of the ground can be treated with 

 success by the methods adopted by Krassilstchik and Snow, but to destroy 

 by contagious disease insects and larvae underground it is necessary, in order 

 to provoke the development of fungi, to thoroughly infect the soil. This is 

 difficult, but not impossible, as is shown by the natural epidemics which 

 decimate the white grub. 



In general, it may be said that the number of entomophytic fungi is very 

 large, and that eventually there will be found a special parasite for every 

 species of injurious insect, or, indeed, that several species will be infected 

 by the same fungus with equal facility. As to their practical application, 

 a very small number of these fungi have been studied and experimented 

 upon. 



