188 "Spotting" of Apples in Great Britain 



lenticel, and there are others of every intermediate stage between these 

 and the largest in the apple. In Ecklinville Seedling nearly every lenticel 

 in the apple is brown and in a large number of them brownness has 

 spread round to form a spot varying from the size of the lenticel itself 

 to one-eighth of an inch in diameter. On Stirling Castle with dark spots 

 the lenticels show up conspicuously brown. On Golden Spire there are 

 dark brown spots on one apple .and pale brown on another, the size of 

 a pin's head. On Lane's Prince Albert received in December 1915 from 

 Berkshire, the smallest spots were of the same dimension as the lenticels. 

 These observations confirm those of Charles Brooks 1 , Barker 2 , 

 Cook and Martin 3 and others as to the importance of the lenticel in 

 relation to incipient " spotting " ; but the lenticels are not the only centres 

 of origin, since the opportunity for infection occurs wherever stomata 

 exist or where the skin is injured by cracks or wounds of any kind. 



Development of "spotting." 



"Spotting" usually appears towards the end of July, and there is 

 a considerable development in August. On September 29th, 1915, 

 "spotting" was observed on 31 varieties at Wisley. The production of 

 new spots goes on continuously throughout the storage period until the 

 coming of spring: over 200 spots were counted on a specimen received 

 from Sussex in 1915. 



The progress of "spotting" was specially studied in a collection of 

 over ninety varieties of apples at the Royal Horticultural Society's 

 Gardens in 1917-18, from two to four specimens of each variety being- 

 examined. Of these, 30 varieties remained free during the season. In 

 some kinds spots developed early in the season and remained without 

 further development; for example, in King of Tomkins County (seasonal 

 period September-April), depressed blackish brown spots up to j in. 

 diameter were present early in November, but remained with little 

 increase in size until May. In others, there was a steady increase in 

 size; thus in Ribston Pippin (November-January) numerous minute 

 brown spots were present early in November: these increased to -gin. 

 (November 22nd) and \ in. in diameter (November 28th); soon after- 

 wards the apples became rotten. In Yorkshire Greening (October- 

 January), there were few depressed brown spots and brown spots with 



1 Brooks, Charles E. Bull. Ton: Boi. Club. 35 (1908), p. 423. 



2 Barker, B. T. P. Ann. Rept. Agr. and Hort. Res. Sta., Long Ashton (1914), p. 98. 



3 Cooke, M. T. and Martin, G. W. Phyt. I.e. 



