W. F. Bewley 119 



above with three yellow blotches on lamina. 21. v. 19. Bottom five leaves wilted; 

 three lowest show yellow blotches; the other two wilted but green with "leaf roll." 

 4. vi. 19. Plants completely wilted. Controls healthy. 



(h) Internodes between Cotyledons and first pair of leaves. 27. iv. 19. Plants 

 inoculated. 12. v. 19. Yellow blotches on first leaf above point of inoculation. 

 14. V. 19. First leaf wilted. 17. v. 19. Second leaf above stab shows a yellow blotch. 

 20. V. 19. Three leaves on one side and one above the other wilted; fourth shows 

 yellow blotch. 7. vi. 19. Leaves all round the plants are wilting. 11. vi. 19. Plants 

 completely wilted. Controls healthy. 



2. Root Inoculation. 



27. iv. 19. Three of the biggest roots per plant inoculated. 20. v. 19. First pair 

 of leaves show yellow blotches. 29. v. 19. Lowest four leaves wilted. 19. vi. 19. 

 Plants completely wilted. Most leaves show "leaf roll" with very little yellowing. 

 Control plants quite healthy. 



3. Soil Inoculations. 



Sterilised soil was inoculated copiously with spores from a pure culture and placed 

 in 6" pots, which were then planted with plants six weeks old. 27. iv. 19. Plants 

 inserted in pots. 17. v. 19. First three leaves wilted. 10. vi. 19. Five plants com- 

 pletely wilted, the remaining one with only four top leaves healthy. 



Inoculations were repeated at monthly intervals and the plants re- 

 acted to infection differently according to the time of year. 



Table I. 



Pathological symptoms 

 Complete wilt; no yellowing 



Lowest 9 leaves turned yellow and partially dried up 

 Lowest 3 leaves desiccated 



Complete desiccation of leaves from base upwards 

 Bottom 4 leaves desiccated, remainder wilted 

 Complete wilt with practically no yellowing 



The preliminary experiments proved the pathogenicity of the Verticil- 

 limn cultures employed, and indicated that the conditions during the 

 months of June, July, August and September are unfavourable to the 

 rapid progress of the fungus in the plants. The hypocotyl and internode 

 inoculations were the first to show typical disease symptoms, but the 

 soil inoculations, although longer in producing first symptoms, produced 

 a complete wilt as soon as the hypocotyl inoculations. Internode in- 

 oculations were slower in producing a complete wilt. Here the fungus 

 travelled up one side of the plant first and produced a wilt on this side 

 only. After a time the fungus worked round the stem and induced a wilt 



