38 



BITTER PIT INVESTIGATION. 



TABLE XVIII. ' 

 RESULTS OF DIFFERENT METHODS OF PRUNING ON LONDON PIPPIN SEASON 1915-16. 



Severe pruning 

 Light 



399 



293 



138 



228 



Leader priming 506 



Clean. Pitted. Per cent. 



On Tree. Windfalls. On Tree. Windfalls. Pitted. 



361 



202 

 131 

 214 



450 



Ibs. Ibs. 

 8 2 



26 (1 apple) 



34 2 



27 4 

 6 1 



13 1 



46 6 



14 10 

 24 8 



38 18 



8 4 



22 3 



30 7 



AMOUNT OF PIT. 



Ibs. 



(a few apples) 1 1 

 9 



2 

 2 



1 



1-3 



7 

 4 



9 



4-2 



3-0 



3-5 



3-2 



2-0 



2-5 



Remarks. 

 Zinc band 



Zinc band 

 Zinc band 



Zinc band 



Although the yield was the highest of all the five years of the experiment, yet the individual 

 apples were rather small, and consequently the development of Pit was not so pronounced. There is 

 no clear distinction, however, between the different modes of pruning and the prevalence of Pit, as in 

 some of the previous years, and the only general remark that can be made about the amount of Pit is, 

 that the light and severe pruning produced about 1 per cent, of Pit respectively, while the absence of 

 pruning and leader priming were responsible for 2| to 3J per cent, of Pit respectively. 



It is the relatively small amount of Pit during the past season which prevents us from drawing 

 any general conclusions, but the relation between "Pit" and "crinkle" in this particular variety of 

 apple may be profitably discussed. 



RELATION BETWEEN "PIT" AND "CRINKLE." 



The London Pippin is rather noted for being subject to distorted and irregular appearances, and 

 to such appearances, which also occur in other varieties, I gave the name of "crinkle" to indicate 

 the general wave-like and irregular contour of the surface. This distorted appearance is called by 

 various names, such as Pig-face, Monkey-face, etc., and it is invariably the case that when such apples 

 are cut across the irregular surface, the skin is found to be unaffected as far as its chlorophyll content 

 is concerned, but the pulp-cells beneath are brown and spongy and shrunken. 



But when this striking appearance is closely observed, it will be found that the ordinary Pits or 

 depressions of Bitter Pit are often associated with it, and in some seasons, such as the present, London 

 Pippin is seen to be subject to Pit, without any trace of the so-called "crinkle" (see Frontispiece). 



As I have already shown, "crinkle" is just an extreme form of Pit, and may be distinguished as 

 confluent Bitter Pit, So that in dealing with this disease, whether in the "discrete" form or "con- 



