STUDIES OF DISEASE PRODUCING SPECIES OF FUSARIUM. 239 



months in which the cultures became dried out at the tempera- 

 ture of the laboratory. 



TESTS OF PATHOGENICITY. 



Appee Inoculations. 



Apples have been inoculated with each of the species of 

 Fusarium isolated from apples and also with strains from other 

 sources and it has been found that those isolated from apples 

 and some of the strains from other host plants cause decays of 

 the fruit which are equal in amount and very similar to the rot 

 caused by P. putrefaciens, F XII, which has been used for com- 

 parison. While these fungi are not so active as causes of decay 

 as the apple rot fungi Sphaeropsis and Penicillium, yet they are 

 capable of causing complete destruction of apples when the con- 

 ditions are favorable for their entrance and growth. 



October 28, 1908, five apples were inoculated with material 

 of F I from a pure culture. The fungus caused a distinct decay 

 and was re-isolated in pure culture from the rotted tissues. 



December 5, 1908, five apples were inoculated with material 

 from a pure culture of F II from apple. The fungus soon 

 showed evidence of growth and at the end of five days each 

 apple showed a small decayed area at the point of inoculation. 

 After two weeks the rot had spread to include an area which 

 was from 1.5 to 2.5 cm. in diameter. Pieces of the decaying 

 tissue were removed with a scalpel which was sterilized by 

 flaming and each piece was placed in a Petri dish which con- 

 tained 10 c. c. of prune agar. The fungus grew out from the 

 tissues in each case and examination proved that the growth 

 was identical with that of the fungus which was used in making 

 the inoculations. The decayed tissue was quite bitter to the 

 taste. 



Ten green apples were inoculated August 10, 1909, with mate- 

 rial from a pure culture of F I. At the end of 4 days an area 

 about 6 mm. in diameter surrounding each point of inoculation 

 was decayed and some white mycelium had developed. The rot 

 spread slowly but at the end of one month the apples varied 

 from one-half to two-thirds decayed. The diseased tissue was 

 light brown in color, soft, and bitter to the taste when held on 



