S. G. Paine and W. F. Bewley 199 



Series 1. 

 31. 5. 19. Brown corky appearance round the stab. 



12. 6. 19. First pair of leaves above the wound showed typical stripe lesions. Fur- 

 rows three inches up the stem. 

 20. 6. 19. Plant typically striped two feet up the stem. 



Series 2. 

 31. 5. 19. Lesions round the "prick" more distinct than in Series 1. 

 12. 6. 19. Furrows nine inches up the stem. 

 20. 6. 19. Lesions more advanced than in Series 1. 



Series 3. 

 31. 5. 19. Discoloration still more intense than in Series 2. 

 12. 6. 19. Furrows up the stem eleven inches. 



20. 6. 19. Five out of the six plants showed lesions in the tops. The sixth one had 

 the top seven inches clean. 

 Series 4. 

 31. 5. 19. Slight discoloration round the "prick." 

 12. 6. 19. Furrows two inches up the stem from the wound. 



20. 6. 19. Very little stripe on four plants, but two showed lesions on the first pair 

 of leaves above the wound. 

 Series 5. 

 20. 6. 19. Very little stripe showing on any plant. 

 Series 6. 



No stripe at aU, except in one case where the plant had rooted through 

 the pot into the rich soil beneath. 

 Series 7. 



Similar appearance to plants in Series 1. 



Series 8. 



Similar to Series 1. 



Series 9. 

 12. 6. 19. Like Series 2. Furrows up to three inches above the wound. 



20. 6. 19. Thii'd pan* of leaves above the wound attacked. 



All controls healthy. 



21. 8. 19. The preceding experiment was repeated with precisely the same results. 



The indications were that increasing amounts of nitrogen without potash 

 produced an increasing susceptibihty to the disease, while increasing 

 amounts of potash without nitrogen gave a corresponding increase in 

 resistance to it. Where potash and nitrogen were used together there 

 were indications that the potash counteracted the effect of the nitrogen. 



CONTROL OF THE DISEASE. 



Several methods are suguested : 



( 1 ) Sterilisation of the soil by heat. 



(2) Sterilisation of the seed by means of formaline. 



(3) Selection of resistant varieties. 



