28 



After these initial transmission tests had been published, 

 I attempted to propagate the parasite S^. invicta . This 

 species is not only the pest we ultimately hope to control, 

 but I have found it easier to obtain and culture than S^. 

 geminata . Several colonies were fed spores and, as expected, 

 successfully infected; however, after two or three months, 

 these colonies were free of the parasite. It appeared then, 

 that B. dimorpha might not be able to maintain itself in 

 factitious fire ant hosts, even though these hosts were 

 readily infected. The studies reported here were conducted 

 to determine the degree of host specificity of B. dimorpha . 

 In addition to fire ants, several species of ants of other 

 genera were tested for susceptibility to infection by B. 

 dimorpha . 



The corn earworm, Heliothis zea (Boddie) (Lepidoptera: 

 Noctuiidae) is susceptible to infection by Nosema algerae Vavra 

 and Undeen, a microsporidium which is highly pathogenic 

 to anophiline mosquitoes. Heliothis zea was being used 

 for mass production of N. alterae spores at the Insects 

 Affecting Man and Animals Research Laboratory, USDA, Gaines- 

 ville, during part of the period in which I conducted my 

 research. I therefore took advantage of the availability 

 of this moth and tested it for susceptibility to infection 

 by B. dimorpha . 



