SLEEPING DISEASE OF TOMATO 263 



that may attack the roots of Tomato plants. In like 

 manner the second stage spores drop to the earth when 

 ripe. They quickly germinate and the mycelium 

 produced may attack the rootlets of Tomatoes. On 

 these points, however, the data are not decisive. Of 

 the third stage or resting spores there is no question 

 of their capability of infection. They are formed in 

 the soil, remain dormant there for a season and then 

 germinate, forming a mycelium, probably at first sap- 

 rophy tic, capable of attacking the rootlets of Tomatoes, 

 and by this means the disease is continued from year 

 to year. 



In no instance has success attended efforts to in- 

 fect above-ground portions of Tomato plants with 

 either Diplocladium lycopersici or Fusarium lycopersici 

 spores. This is remarkable, and as the young rootlets 

 of the Tomato are the only part of the plant through 

 which the fungus gains admission to its interior, the 

 deduction may be drawn of the fungus beginning life 

 as a saprophyte and of even mainly leading that, 

 though also capable of becoming parasitic. 



Prevention. As the disease is wholly internal and 

 infection on the aerial part of the plant not feasible, 

 spraying with fungicides is worse than useless. As the 

 fungus begins life as a saprophyte, it is obvious that 

 the best preventive will be to avoid green manure, 

 either as an application to the soil or as a top dressing, 

 for a saprophyte must have at command dead and 

 decaying organic substance to exist. The manure, or 

 such substances as leaf mould and even turfy loam, with 



