192 "Spotting" of Apples in Great Britain 



As regards the frequency with which a particular fungus occurs alone 

 in spots, data can only be given for Pleospora pomorum and fungus b ; 

 the former was found unassociated in eight out of nine varieties studied 

 (in the ninth case Polyopeus purpureus was present in addition) ; in the 

 latter, in 12 out of 15. 



Taking into account the total number of spots of all categories, 

 Pleospora pomorum 1 has been isolated from 18, Polyopeus purpureus 

 from 20 varieties. Only six of these varieties yielded both fungi. 

 Alter naria grossularieae occurred in seven varieties of which two (Byford 

 Wonder and Ben's Red) also yielded Pleospora, and four (Early River, 

 Grenadier, Rev. W. Wilks, and September Beauty) Pohjopeus purpureus. 



The apples from which Pleospora pomorum has been isolated are 

 by no means of a similar class; they include dessert (Cox's Orange, 

 Ben's Red), culinary and dessert (Bramley's Seedling, Wealthy), and 

 culinary (Byford Wonder) sorts; also varieties in season in late autumn 

 (Loddington), and in winter (King of Tomkins County). Polyopeus 

 purpureus occurs also in both culinary and dessert varieties, and notably 

 in the culinary varieties Newton Wonder and Lane's Prince Albert, 

 varieties with a wide seasonal range, but it also occurs in varieties with 

 a restricted range as Grenadier. 



Fungus b has been isolated from dessert and culinary sorts — Al- 

 friston (Nov.-Apl.), Lord Hindlip (Jan.-May), Belle de Pontoise (Dec.- 

 Feb.), Duke of Devonshire (Mar.-Apl.), etc. — chiefly from apples in 

 season after November. 



The surface spots present on apples badly affected with "bitter pit" 

 frequently yielded fungi; for example, on Newton Wonder some spots 

 yielded Cladosporium epiphyllum, others Dematium pullulans and 

 fungus b, others slow-growing unidentified fungi (minute dark brown 

 spots). Fungi were not obtained from "spotted" specimens of Calville 

 Boisbunel, Crawley Beauty, Sanspareil and Yorkshire Greening. 



The largest spot-flora has been obtained from Cox's Orange Pippin 

 — eight species excluding unnamed fungi : two fungi were obtained from 

 Blenheim Orange, fungus b from small spots and later Myxosporium mail 2 

 from areas where rot had set in. 



Of the important culinary varieties, Lane's Prince Albert yielded 

 Dematium pullulans four times, Polyopeus purpureus, recurvatus, and 



1 The earliest date on which it has been obtained is Nov. 15th (Charles Ross), and the 

 latest, early in March (Bismarck). 



2 Also isolated from Byford Wonder, Domino, Duke of Devonshire, Lord Grosvenor, 

 Lord Suffield, Rev. W. Wilks, Winter Hawthornden. 



