1126 Keversion of Blackcurrants. [Mar., 



For convenience of comparison, the points already discussed 

 have been summarised in the table given below. The method 

 of identification described above has enabled the course of the 

 disease to be followed in considerably more detail and with 

 greater accuracy than hitherto. The results obtained cannot 

 be described here through lack of space, but they show that a 

 reverted bush may start the season by producing perfectly 

 normal leaves. This, however, does not continue long, perhaps 

 only for a few leaves, but it means that in the early part of 

 the season no attempt should be made to identify the disease 



Table. 



Figure. 



No. of Submain 

 Veins. 



Character of 

 Margin. 



Serration. 



No. of 

 uninnervated 

 pointlets. 



1 



5 



Normal 



IT" 



Fine 



8 



2 



5 



Slightly 



Fairly 



4 







reverted 



fine 





3 



4 



Reverted 



Coarse 



2 



4 



3 



Reverted 



Coarse 



2 



5 



2 



Intermediate 



Very 











oak leaf 



coarse 





6 



2 



Oak Leaf 



Very 













coarse 





7 



1 



Oak Leaf 



Very 













coarse 





by this method. By the middle of May, reverted leaves begin 

 to appear, and from this time until the end of June is the 

 period when the disease is most readily recognisable. This 

 fact has long been known to practical growers who do their 

 rogueing at this period of the year. It can, however, be done 

 at any later period until the leaf drops, though the process 

 is not quite so simple. In July or August, the May- June leaves 

 do not show at the top of the bush, and since the reverted 

 leaf type is most marked in May- June, more care must be 

 taken. In many cases, the July-August leaves are also 

 abnormal, and though frequently only to the extent shown bv 

 Fig. 2, the grower who has trained his eye by the method 

 described in this paper will soon be able to pick out such leaves. 

 All he has to do is to turn back the branches and look for 

 the leaves produced in May- June. If reversion is present, the 

 leaves will show it quite clearly. 



Practical Conclusions. — As mentioned above, in the present 

 state of knowledge regarding the disease, the grower has two 

 methods of attack. The first consists of propagation from sound 



