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KILLING DESTRUCTIVE LOCUSTS WITH FUNGOUS DISEASES. 



By Lawrence Bruner, Temporary Field Agent. 



The fact that various kinds of insects are at times attacked and 

 destroyed by different species belonging to several distinct genera of 

 fungi has been known to both botanists and entomologists for many 

 years. It is, however, a matter of comparatively recent discovery that 

 some of these fungi can be artificially grown and afterwards commu- 

 nicated to the insects which it is desired to destroy. Numerous exam- 

 ples of the propagation and spread of such fungi have been recorded 

 in this and other countries. Some noted examples of this kind are the 

 artificial spread of Isaria densa Link, the fungus that attacks the 

 European cockchafer and that has also been tried on the white grubs 

 here in the United States; Sporotrichum globuliferum Spag. as used 

 against the chinch bug and several other insects, and Errvpusa muscde, 

 the common fungus of the house fly. Along with what has been 

 recorded concerning these attempts at utilizing the fungi just men- 

 tioned, it might be well here to outline some of the efforts that have 

 been made during recent years toward lighting destructive locusts or 

 grasshoppers by similar means. It is not necessary, however, for one 

 to devote much time in investigation to ascertain that the whole matter 

 relating to this subject is still in great confusion. It will at once be 

 apparent that nothing very definite 1 exists in the shape of reliable infor- 

 mation concerning the particular fungi that may be present and avail- 

 able in each of the regions where there is need for waging war against 

 the locust plague 1 . Even the botanists who are interested in this group 

 of plants seem to have done comparatively little toward isolating and 

 separating the species, from tin 1 standpoint of the systematist. 



During the early seventies, when such vast swarms of the Rocky 

 Mountain or migratory locust were devastating the country between 

 the Mississippi River and the Rocky Mountains, attention was fre- 

 quently called to an apparent disease which occasionally made its appear- 

 ance among the devouring hordes of that pest in various sections of 

 the country. After a little investigation on the part of members of 

 the Entomological Commission and others, this fatality among the 

 locusts was found to be due to the presence of a fungus which is now 

 generally recognized as Erri/pusa grylli, although it has been several 

 times described under other names. 



AVhile locusts in general are more or less frequently attacked by 

 these fungi, particular ones among the locusts indigenous to each 

 country seem to be more subject than others. These usually, though 

 not alwa} T s, happen to be the forms that at times become so greatly 

 multiplied as to be pests. This fact would indicate that it is necessary 

 for the insects to come in contact one with another in order to spread 

 the fungus sufficiently to develop an epidemic. 



