4io DISEASES OF CULTIVATED PLANTS 



amount of food, and the growth of the tubers is more or less 

 checked. 



Perithecia immersed in the tissue of the host, 130-T45 \i 

 diam. Conidia elliptic-oblong, 7*5 X 3 /'. 



Prillieux, Malad. des Plantes Agric, 2, p. 296 (1897). 



MACROPHOMA (Sacc.) 



Only differs from Phoma in the larger conidia and un- 

 branched conidiophores. 



Yew leaf blight {Macrophoma taxi, Berl. and Vogl.) 

 attacks living leaves of Taxus baccata^ causing them to turn 

 brown, but they do not fall for some time. Not infrequently 

 whole branches are attacked, and are very conspicuous. 



The small black, sunken perithecia are scattered on 

 the under surface of the leaf, or sometimes arranged in an 

 irregular line on each side of the midrib. A few perithecia 

 are sometimes present on the upper side of the leaf. Spores 

 elliptic-oblong, 20-24X9-12 /'. 



Attacked branches should be removed to prevent further 

 infection. 



PHYLLOSTICITA (Pers.) 



Perithecia formed under the epidermis, lenticular, mem- 

 branaceous, mouth or pore of dehiscence often protruding, 

 seated on discoloured spots on leaves, rarely on shoots; 

 conidia minute, elliptical or oblong, continuous, hyaline or 

 tinged with olive. 



Australian shot hole fungus ( Phyllosticta prunicola, 

 Sacc.) attacks living leaves of apple, pear, plum, cherry, 

 apricot, etc., producing effects similar to those due to the 

 European shot-hole fungus (Cercospora circumscissa). Small 

 brownish spots first appear on the upper surface of the 

 leaves, which become dry and brittle, and eventually drop 

 out. giving to the leaf the appearance of having been riddled 

 with small shot. Very minute perithecia are tormed on the 

 diseased spots. The fungus occurs in Western Europe, 

 United States, and in Australia. 



Perithelia scattered, dot-like, slightly prominent ; conidia 

 ovoid or elliptical, dilute olive, 5 X 3 fi 



Usually not very destructive, unless especially abundant 

 on young stock, when spraying with Bordeaux mixture is 

 recommended. 



