Natural vector.—Periplaneta americana, England (Bunting, 1956): The fungus was isolated mostly from imperfectly excreted feces.
Beauveria bassiana (Balsamo) Vuillemin
Experimental host.—Blattella germanica and Periplaneta americana, U.S.A. (Dresner, 1949, 1950): The nymphs of American cockroaches became infected when they (1) were injected with a 1-percent suspension of spores, (2) ate rat pellets sprayed with the spore suspension, or (3) were dusted with the fungus spores. The symptoms of the fungus infection were paralysis followed by death; some of the infected insects liquefied, others dried up after the appearance of a subcuticular blackening.
Cephalosporium sp.
Natural vector.—Periplaneta americana, U.S.A., Texas (McShan, unpublished MS., 1953): From feces of cockroaches collected in the basement of a grain elevator at the docks in Galveston.
* Geotrichum candidum Link
Experimental vector.—Blatta orientalis, Italy (Cao, 1898): Organism retained its pathogenicity after passing through the insect's gut.
Penicillium sp.
Natural vector.—Blaberus craniifer, U.S.A. (Wedberg et al., 1949): From feces.
Periplaneta americana, England (Bunting, 1956): Mostly from imperfectly excreted feces.