452 DISEASES OF CULTIVATED PLANTS 



Spores 5-6-celled, end cells hyaline, terminal cells with 3-4 

 slender, hyaline spines; spores 54-60x16 //,; spines up to 

 80 /A long. 



Wagner and Sorauer, Zeitschr. Pflanzenkr.^ 8, p. 266 (1898). 



ENTOMOSPOEIUM (Lv.) 



Perithecia spurious, globose depressed, black, mouthless ; 

 conidia of two superposed cells, with two or more cells spring- 

 ing from the median septum, all the cells bearing delicate 

 hairs. 



Leaf scald, due to Etitomosporium macula turn (Lev.), 

 often proves very injurious to pears; it also attacks apple, 

 peach, cherry, quince, and other fruit-trees belonging to the 

 family Rosaceae. I almost invariably find the fungus fruiting 

 first on the shoots of the previous season, where it occurs on 

 small, dingy red, slightly depressed spots. The fact that the 

 disease can frequently be found on the young leaves of buds 

 that are only just unfolding, suggests that the mycelium 

 present in diseased shoots travels into the buds and infects 

 the leaves. On the leaves, most obvious on the upper surface, 

 the disease first appears under the form of a number of small, 

 round, red spots. These spots gradually increase in size and 

 run into each other, forming irregularly shaped blotches, 

 which change to a brownish colour, and show a few project- 

 ing black spots, the fruit of the fungus. When the leaves 

 are attacked when quite young they soon turn brown, shrivel, 

 and fall early. When older leaves are attacked they do not 

 shrivel, owing to their rigidity, but soon fall. The fruit is 

 also attacked ; the spots are at first red, afterwards becoming 

 brown, and extending their size as on the leaves. The flesh 

 sometimes cracks, as when attacked by pear scab. When 

 spores are placed on a young, living leaf, minute, red spots 

 appear in about five days, and if the weather remains dull 

 and moist, mature spores, capable of infection, are produced 

 at the end of three weeks. On older leaves the whole process 

 of development is slower, and in some instances the disease 

 only forms, small red spots which do not produce fruit. I 

 have not succeeded in infecting young cherry leaves with 

 spores obtained from a pear leaf, although some of the same 

 gathering of spores infected other pear leaves. 



