206 



The Philippine Journal of Science 



Fin. 16 Kkizoctonia. Mycelium from pure 

 culture of fungus (X 340), iso- 

 lated from Glycine max (Linn.) 

 Merr. (G. hispida Maxim.). 

 Note characteristic branching. 



Causal organism. — The fun- 

 gus mycelium penetrates to all 

 diseased portions, undoubtedly 

 producing an enzyme, which 

 aids in disintegration. Numer- 

 ous inoculation experiments have 

 been carried on, using different 

 beans as hosts. Sclerotial bod- 

 ies from pure cultures were 

 merely placed on leaves or tender 

 stems, and the plants were 

 put under bell jars. Within 

 two days infection and blight 

 were produced. Sclerotial bod- 

 ies produce mycelia direct and 

 infect injured or uninjured 

 portions. Within one week the 

 entire plant is blighted and 

 falls over in a soft mass (Plate 

 IX, figs. 2 and 3) . Later sclero- 

 tial bodies are formed on these 



diseased plants. The advance 

 of the fungus can be retarded 

 or completely stopped by remov- 

 ing the bell jars and putting 

 the plants in the sun. Reisola- 

 tion from infected plants pro- 

 duced the same fungus used 

 for inoculation. At no time 

 in diseased fields or on pure 

 cultures have spores been ob- 

 served. Attempts to produce 

 spore-bearing bodies and spores 

 from sclerotial bodies have thus 

 far failed. The mycelium is 

 typical of Rhizoctonia (figs. 16 

 and 17). 



In the cross inoculations cul- 

 tures obtained from Glycine 

 max (Linn.) Merr. (Glycine 

 hispida Maxim.), Voandzeia 

 subterranea Thou., and Phaseo- 



FlG. 17. Rhizoctonia. Mycelium from scle- 

 rotial body, growing in pure 

 culture (X 340) ; a, formation 

 of sclerotial body ; 6, portions 

 of sclerotial body. Isolated 

 from Glycine max (Linn.) 

 Merr. (G. hispida Maxim.). 



