P. A. VAN DBR J5IJL '27 \ 



were incubated at 25° C. After five days there was a pun' w 1 1 i 1 « • , fluffy, 

 mycelial growth from the pieces of carnation, and on this growth 

 spores typical of the genus Fusarium. 



On two more occasions this Fusarium was isolated from wilting 

 plants growing in the same tin. The fungus was also obtained from 

 specimens submitted by Mr G. E. Ensor of Pretoria: the disease also 

 causes serious monetary loss to carnation growers in the Province of 

 Natal. 



2. Inoculation of munitions with the fungus in pure culture. On 

 the 17th February, 1914, carnation plants growing in tins at the labora- 

 tory were inoculated with the causal fungus thus : the soil was slightly 

 removed round the stems of the plants, which were then punctured, 

 just below the natural soil level, with a sterilised needle. Into the 

 punctures were inserted pieces of the fungus growing in pure culture 

 on beef-broth agar, and the soil was replaced. On the 27th February one 

 of the inoculated plants had wilted with the usual symptoms. Pieces 

 of diseased tissue of this plant were fixed in picroformol (formol 30 c.c, 

 glacial acetic acid 5 c.c, water 20 c.c. and the mixture saturated with 

 picric acid) and embedded in paraffin for further study. Beef-broth 

 agar plates were prepared with pieces of diseased tissue and in these 

 the same Fusarium developed. By the 4th March another of the 

 inoculated plants had wilted with the characteristic symptoms mentioned 

 above, and here too the same fungus was isolated. 



In the same tin with the inoculated plants were left controls which 

 were treated similarly to the inoculated plants in every way except 

 that the fungus was not introduced into the punctures. These controls 

 remained healthy. 



Successful attempts at inoculation were also made by burying 

 next to the plants cultures of the fungus. The carnations experimented 

 on were again grown in large tins. The soil round the stems of the 

 plants in one tin was removed; in the holes were placed cultures of 

 the fungus on rice and the soil was then replaced. Four days later some 

 of the plants showed a sickly appearance. On the seventh day one plant 

 was noticed with lower leaves sickly white and upper leaves flaccid; 

 and when this plant was pulled up it was observed to have the charac- 

 teristic crown-rot. On the 13th day three more diseased plants were 

 observed in this tin, and on the 17th the last plant had contracted 

 the disease. 



Plants growing in a tin next the inoculated tin remained healthy 

 during this time. 



