120 



''Sleepy Disease'' of the Tomato 



on all sides of the plant. During 1920 cultures were re-isolated from 

 plants kept over the winter months and inoculation experiments per- 

 formed to ascertain the effect of various environmental conditions upon 

 the progress of the disease. 



1920. 



4. One re-isolated strain, V 33, was tested for pathogenicity and 

 gave the first symptoms of the disease eight days after inoculation; 

 complete wilt occurring one month after this. Further experiments were 

 performed with this strain. 



5. To ascertain the relation of the character of the plant to the 

 progress of the disease, plants in different stages of growth and of varying 

 degree of hardness and softness of growth were inoculated (a) by hypocoty 1 

 stab, (6) by planting in inoculated soil. The results are shown in Table II. 



Table 11. 



The observations shown in Table II indicate that plants grown hard 

 with a thin stem, or plants obviously starved, most readily succumb to 

 the pathogen in question. As there was very Uttle difference in the 

 result of the two kinds of inoculation, only those obtained by planting 

 in infected soil are tabulated; these being the more comparable with 

 those of plants naturally infected in the nurseries. 



6. Inoculation of sterile seedlings. 



The positive results obtained by growing young tomato plants in 

 soil inoculated with a pure culture of Verticillium, does not eUminate 

 the possibility that infection by this fungus may only be possible where 

 the plant has been wounded previously. Under such conditions no obvious 

 wounds may exist, but minute lesions may be present. Experiments 



