13S FL*NGI AS ANTAGONISTS 



pampeana^ for example, normally does not form any peritheda in cul- 

 ture but is able to do so in the presence of Basis porium gallarum or 

 Fiisjriuf77 momliforme. This effect was ascribed to a special substance 

 that resists heating at i io~ C. Different fungi have a special influence 

 on the germination of spores of various ascomycetes and of other fungi 

 (25, 742), these effects being characteristic of the antagonists. 



The edible mushroom, PsalUota campestris^ exerts a deffnite antago- 

 nism against the parasitic fungus My co gone (124). This phenomenon 

 has been looked upon as a case of antibody formation. %>edes of Fusor- 

 r'lum are able to antagonize the mushroom fungus \ however, an actively 

 growin-g culture of the latter may become antagonistic to the former 

 (998). In the destruction of paper pulp by fungi, a marked antagonism 

 was shown {^I'l) ^^ take place between different organisms, especially 

 h\ Trichoderma Ugnorum against various species of Fusarium and other 

 fungi, as illustrated in Figures 14 and 15. 



Certain spedes of Trichoderma and Gliodadium are able to inhibit 

 the growth of various plant pathogenic fungi, especially R. solani, as 

 well as of Blastomycoides derm-atitisy a causative agent of human skin 

 diseases (962—964). The active substance, gliotoxin, is liberated during 

 the early stages of growth. The mycelium of older cultures contains an- 

 other substance that is soluble in acetone j this has only an inhibiting ef- 

 fect and is not fungicidal as is gliotoxin. The fungicidal effect of glio- 

 toxin upon the germinating sp>ores of Sclerotwla americana and hv'phae 

 of R. solani was found to be greater than that of CUSO4 and less than 

 that of HgCU. 



\'arious other fungi are able to exert antagonistic effects against plant 

 pathc^ns. T. lignorum and A . mger restricted the growth of the fungi 

 Macrophomina phaseoU and R. solani^ which produce cotton root rot, 

 and reduced the activity of the filtrates of the pathogens causing wilting 

 of the plants C911). 



Satoh (788) has shown that Ophiobolus miyaheanus produces both 

 growth-promoting and growth-retarding substances, the first of which 

 is heat stable and passes through a Chamberland filter j the second is 

 inactivated at ICX)^ C. and does not pass through a filter. The formation 

 of two substances by Torula suganiiy both of which were thermostable, 

 however, was also demonstrated (654). 



