192 Apple Canker Fungus — Leaf Scar Infection 



REFERENCES. 



(1) Wiltshire, S. P. (1913, 1914, 1919). Ann. Rept. Research Station, Long Ashton. 



(2) Cayley, D. (1921). Ann. Bot. xxxv, 79-92. 



(3) Goethe, R. (1904). Uher den Krebs der Ohstbaume, Berlin, p. 16. 



(4) Wiltshire and Spinks (1920). Ann. Rept. Research Station, Long Ashton. 



(5) Grubb, N. H. (1921). Journ. Pomology, n, 93. 



(6) Barker, Gimingham and Wiltshire (1919). Ann. Rept. Research Station, Long 



Ashton. 



EXPLANATION OF PLATE ML 



Fig. 1. Early stage in the infection of a shoot of Devonshire Quarrenden. The fungus 



entered at the edge of the leaf scar and the boundary of the infected tissue can be 



distinguished. March 1920. x 1. 

 Fig. 2. Infections on Kingston Black x MedaiUe d'Or seedlings. The infections are about 



three months old. At ^, a portion of infected tissue can be seen isolated and excluded 



from the stem. August 1920. x f . 

 Fig. 3. Typical leaf scar infections on Tom Putt, Middle Winter Pippin and an unknown 



variety of apple. Note that each scar surrounds a bud. August 1920. x |. 

 Fig. 4. Cankers on the 1917 and 1918 wood of Bramley's Seedling, probably developed 



from leaf scar infections. August 1920. x ^. 



{Received May 2nd, 192L) 



