204 .1 niossouf Wilt (hkJ ('((nhi'r of Apple Tvev>^ 



(18) Salmon, E. >S. The "Brown Rot" Cunker of tlic Api)k'. .louiii. Soutli-Eastern 



Agric. Coll. Wye, No. 22, pp. 446-449, 1913. 



(19) The "Brown Rot" Canker of the Apple. Card. Chron. Vol. lvi. j). 8.j, 



Aug. lis 14. 



(20) Smith, W. E. Diseased Apple-lwigs. (Kept, of the Scientific ConMiiittee of 



the Roy. Hort. Soc.) Card. Chron. Vol. xxv. (Third Series), p. 12.5, 1899. 



(21) SoriAUKR, P. Die Schiiden der einheinuschen Kulturpfian/.en durch tliierische 



uiid pfiaiizHelie Schmarotzers. Berlin, 1888, p. 230. 



(22) Spinks, G. T. a Black Rot of Apples. Ann. Rept. of the Agric. and Hort. 



Research Sta. Long Ashton. Bristol, 191.5, pp. 94-96. 

 (2.3) WoKONiN, M. tJber Schroluiia cinerea und Sderoiinia fruclicjcna. I\Ieni. 

 Acad. Imp. Sci. St Petersbourg, viir. Series. Vol. x. No. 5. Phys. Math, 

 pp. 1-38. Oct. 1899. 



DESCRIPTION OF PLATES XXII XXIV. 



Fig. 1. Portion of cankered branch (var. Lord Derby) showing Monilia pustules; con- 

 dition as seen in winter. (Photographed April 8, 1916.) 

 Fig. 2. Dead spur and canker bearing Monilia pustules, with neighbouring flowering 



spurs ; the wilted trusses below the canker were probably infected by conidia falling 



from the spur and canker; condition as seen in summer. (Juno 4, 1915.) 

 Fig. 3. Four trusses on the main stem of a young Lord Derby apple tree ; the first and 



the third (from above) were each inoculated, from a pure culture of the fungus, on 



a single flower. Result fifteen days after inoculation — both inoculated trusses are 



dead. 

 Fig. 4. As in Fig. 3 but four weeks later; the stem is cankered above and below the two 



inoculated trusses. 

 Fig. .5. The stem of the infected tree at the time that the photograph shown in Fig. 3 



was taken ; the four trusses there shown are to be seen immediately below the branch 



on the right. 

 Fig. 6. As in Fig. 5 but taken four weeks later, i.e. on the same day as Fig. 4 was obtained. 



The leaves on the branches above the canker are wilting. 

 Fig. 7. A canker produced by a natural infection in 1914: it bore Monilia pustules in 



1915, but when photographed in June 1916 was barren and was being covered over 



by callus. 

 Fig. 8. The canker shown in Fig. 2 seen in transverse section (x 2i). The development 



of callus at the sides of the canker has already commenced at this stage. 

 (Figs. 1 — 4 and 7 arc % natural size.) 



I 



CAMBRIDaE: PRINTED BY J. B. PEACE, M.A., AT THE UNIVERSITY PRESS. 



