250 



Bitter Pit in Cape Apples.-Since the publication of previous 

 notes on this subject (K.B. for 1906, pp. 193-5, and K.B. for 1907, 



pp. 112-k), it has transpired that prior to the official reference of 

 this interesting question to Kew for report, on 26th March, 1906, 

 the subject had already been placed in the very competent hands 

 of Professor J. B. Farmer, F.R.S., Royal College of Science, South 

 Kensington, for investigation. Knowing the great interest taken 

 in the matter at Kew, and sharing our feeling that it is desirable 

 to place at the disposal of all who are, or are likely to become, 

 interested in the subject the whole of the information as vet 

 available, Professor Farmer has very kindly supplied the sub- 

 joined note for the information of readers of the Kew Bulletin \ 



" With reference to the note on Bitter Pit in Cape A.pples which 

 appeared in the Kew Bulletin, Xo. 4, 1907, 1 should like to say 

 that my own attention was called to the disease about 18 months ago 

 by Dr. Horace Brown, who showed me some specimens preserved 

 in spirit. I was introduced by him to the Cape Orchard Company, 



wno were good enough to send me several consignments of various 

 sorts of apples for investigation. In the badly attacked sorts (e.g., 



f° l 2 " V Py ) fche disease was not confined to any special region 

 ot the apple. All attempts to establish a fungal or bacterial origin 

 lor the disease failed. No truce of either could be seen in sections 

 ot the fruit, either fresh or preserved in the fixations commonly 

 employed in microscopic technique. This is of itself not conclu- 

 sive, tor it is well known how easily the parasite may escape 

 detection under these conditions. But cultural experiments 

 carried on on a rather large scale also failed to reveal the slightest 

 trace of any existing parasite. 



Furthe 



,i flT , , .,, . ' ~~«w^ a^vmo, a» iur. j-mvis »uut?s, (»"«t° "" 



develop ivithin the flesh of the apple, and to extend outwards to 

 tne sfcin. Several of the samples I received showed no traces of 

 me disease till they were cut open, and then the characteristic 

 Drown spot was easily enough identified. Thus it seems clear 

 mat the disease is connected with— at present— obscure physi- 

 ological causes which can only be investigated on the spot, 

 unless it should turn out that some plant louse or other animal 

 starts the mischief by boring into the fruit when very yoi 



young 



lar 



great 



h 4- i u uc ot e ie "« interest, auu wm^u >»"* 



nave to be borne in mind in seekine for the explanation of the 

 origin of the malady. The cells of the affected area are always 

 run ot starch, and stand out in this respect in marked contrast 

 to the surrounding healthy tissue. Either the pathological condi- 

 tion tends to effect the formation of the starch, or, as I think is 

 more + probable, the action of diastase is locally inhibited. This 

 ™,„ + £ „ inability of sugar to pass out of the infected 



asing its concentration, to maintain a high 



cell, and so by increasing 

 starch content, or it 



action On thft rliaa+ac 



The cell walls undergo a kind of 



legr 



Red. The whole disease bristles with points of physiological 

 interest, but they can only be hopefully attacked on the spot." 





