194 



"Spotting" of Apples in Great Britain 



control punctures were made on a third apple. On Feb. 22nd, brown 

 spots \ in. diameter were observed, but again spots appeared at places 

 not inoculated. However, on Feb. 28th, the four spots formed at the 

 points of inoculation on this apple had coalesced to form an area 1 in. 

 in diameter. The apple was then cut open and portions of diseased tissue 

 were removed from the interior at a depth of \ in. from the surface. 



Fig. 3 (a). Apple inoculated with conidia of Pleospora at two points, after two weeks 

 (see Fig. 2 a for photographic reproduction of the same apple after seven weeks). 



(b) Apple affected with "spotting," March, 1915. 



(c) Apple showing rot (shaded portion) following "spotting." 



(d) Apple inoculated with conidia of Pleospora at four points, after seven weeks, showing 



infertile perithecia (see Fig. 2 h for a photographic reproduction of the same apple). 



Some portions were placed in sterile petri dishes and others on the surface 

 of apple agar in slant tubes. After a few days abundant conidia and 

 later sterile perithecia of Pleospora were formed in both dishes and tubes. 

 Experiments were then made with known varieties. Specimens of 

 Lane's Prince Albert and Newton Wonder were inoculated on March 14th. 

 In the case of Lane's Prince Albert a spot about § in. in diameter was 

 present on April 3rd, increasing to a pale brown area with dark centre 



