SCLEROTINIA 271 



in Europe. The fruit-grower in most instances is only 

 acquainted with the fungus as it occurs on ripe or nearly ripe 

 fruit. As a rule, however, the fungus first appears on the 

 leaves or young shoots ; it sometimes also grows on the 

 flowers. 



When leaves are attacked the mycelium spreads rapidly in 

 the tissues, and soon gives origin to very thin dark olive- 

 green patches on the surface of the leaf. These patches 

 consist of dense masses of barrel-shaped spores produced in 

 chains. When mature these spores are scattered by various 



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Fig. 80. Sclerotinia fructigena. 1, conidial form {Monilia 

 fructigena) on an apple ; 2, a pustule of the conidial form ; 

 3, a chain of conidia. Figs. 2 and 3, mag. 



means, and infect other leaves, also young shoots and fruit. 

 I have observed the fungus to be especially partial to cherry 

 blossom, where it forms minute velvety tufts on the flower 

 stalk, sepals, and petals, which in consequence turn brown, 

 and eventually die. This effect is usually attributed by 

 gardeners to a touch of frost. On young shoots the fungus 

 also forms velvety olive-brown tufts, but as a rule the twig is 

 not killed the first season. On such infected twigs the 

 mycelium of the fungus survives the winter, and the first 

 spores of the season are often formed on these twigs. These 

 spores in turn infect the young leaves and fruit. 



The mode of growth is somewhat different on different 

 kinds of fruit. On apples the fungus fruit is preceded by a 

 brown decayed patch, which soon becomes covered with 



