W. F. Bewley 131 



Another source of infection, which becomes more and more evident, 

 is the contamination carried in "strikes" or baskets, and a considerable 

 number of cases have been noted, where infection with various diseases 

 has been traced to these articles. Baskets may be so mixed at the market 

 that when they are returned, those from one nursery are sent to another, 

 and so disease is spread. Baskets should not be taken near the growing 

 plants for fear of introducing some new trouble, and during the winter 

 months all baskets should be sterihsed in readiness for the coming season. 

 The importation of young plants from other nurseries is a procedure to 

 be deprecated, for it is a fruitful means of disease dispersal. Contaminated 

 water from surface wells is a constant source of infection with many 

 diseases (1), and care should be taken to use a pure water supply. V. albo- 

 atrum will infect a large number of cultivated plants, as well as certain 

 trees, and while there is yet no direct evidence to show that the fungus 

 may attack the common weeds around nurseries, it will probably be 

 found that such is the case. It is desirable, therefore, that the immediate 

 vicinity of nurseries be kept free from weeds, while potatoes and antir- 

 rhinums should not be permitted as they are susceptible to Verticillium. 



In America, tomatoes resistant to the Fusarium Wilt Disease have 

 been produced and an attempt is being made in this laboratory to raise 

 a Verticillium resistant strain. 



The author desires to express his gratitude to Dr W. B. Brierley of 

 the Rothamsted Experimental Station for the many helpful suggestions 

 and criticisms so kindly given during the course of this work, also to 

 Mr W. Buddin, M.A., late assistant mycologist at this station for 

 assistance in the preparation of the enzyme extracts. 



SUMMARY. 



1. "Sleepy Disease" or "Wilt" of tomatoes may be caused by one 

 of two fungi, Fusarium lycopersici or Verticillium albo-atrum. 



2. Massee's " diplocladium stage" of F. hjcopersici has been shown 

 to be V. albo-atrum. 



3. The wilt producing fungi attack the roots and grow up through 

 the vascular bundles into the stem, leaves and sometimes the fruits. 

 The wood of a diseased plant is a hght or dark brown colour. 



4. The average temperature is a "Kmiting factor" in determining 

 which fungus is active. F. lycopersici grows best at an average tempera- 

 ture of 27-8-28-9° C. If the temperature remains constantly much below 

 this, little infection results. V. albo-atrum develops well at temperatures 



