JOIMAL OF AGRKETIIAllSEARCH 



Vol. XVIII Washington, D. C, January 15, 1920 No. 8 



FURTHER STUDIES OF SOROSPORELLA UVELLA, A 

 FUNGOUS PARASITE OF NOCTUID LARV^ 



By A. T. SpEare, Mycoentomologist, Deciduous Fruit Insect Investigations, Bureau 

 of Entomology, United States Department of Agriculture ^ 



INTRODUCTION 



Because of their peculiar mode of life and varied characters, the Fungi 

 Bntomogeni, or fungous parasites of insects, possess an unusual interest 

 and have formed the subject of a number of classic papers in mycological 

 literature. Not only are they of interest from a scientific point of view, 

 but they possess an economic importance which is probably much greater 

 than is generally supposed. 



While the majority of mycologists are likely to overlook these fungi 

 through a lack of familiarity with insects and their habits, it is equally 

 true that an ignorance of mycology has usually led entomologists to give 

 them at best but scant attention, even when their presence is evident. 

 That they are often overlooked is due further to the fact that even in 

 destructive forms their development usually takes place within the living 

 insect. The externally visible growth which occurs, if at all, after death 

 is usually more or less concealed because of the position of the host at this 

 period ; and in many instances it may be so evanescent that after a rela- 

 tively short interval the cause of death can not be determined. 



The fungi of this nature which are of economic importance belong for 

 the most part to one of two categories, the Entomophthorales and As- 

 comycetales, while associated with the latter may be distinguished a third 

 group of entomogenous " Fungi Imperfecti," which although assumed for 

 the most part to be imperfect stages of ascomycetous forms, have not 

 been definitely connected as yet with any perfect or acigerous condition. 



In all the groups the economic value of the parasites concerned is due 

 to the fact that their cycle of development may be a very short one and 

 that in all cases an enormous provision is made for reproduction, a provi- 

 sion vastly greater than that of any of the many types of parasitic insects, 

 an increasing number of which are now being used in an effort to control 

 noxious forms. 



1 The writer wishes to express his appreciation to Dr. Roland Thaxter, of Harvard University, for helpful 

 criticism of the work while it was in progress, and to Mr.W. H. White, of the Bureau of Entomology, United 

 States Department of Agriculture, who first found the parasite. 



Journal of Agricultural Research, Vol. XVIH, No. 8 



Washington, D. C. Jan. 15, 1920 



ti • Key No. K-79 



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