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Brown Rot of Fruit. 



Brown Rot of Fruit. 

 {Sclerotinia fructigena. Schroter). 



This is undoubtedly one of the most general, and also the 

 most destructive of diseases against which the fruit grower has 

 to contend. It attacks apples, pears, plums, cherries, peaches, 

 and is also not uncommon on various wild fruits belonging to 

 the order Rosacea, as bull ace, crab, etc. 



To the ordinary observer this disease first attracts attention 

 when it appears on the fruit under the form of brownish 

 scattered patches on the skin. This is followed by the growth 

 of dull grey tufts (the so-called Monilia fungus), which are 

 usually arranged in irregular concentric rings. These grey tufts 

 are composed of dense masses of spores arranged in long 

 branched chains. 



The fairy-ring arrangement of the fungus is most evident on 

 apples and pears ; on plums, cherries, and stone fruit generally, 

 the grey tufts are irregularly scattered over the surface. 



Although most obvious on the fruit, the fungus usually first 

 attacks the leaves, where it forms thin, velvety, olive-green 

 patches. The spores from diseased leaves are washed by rain, 

 or carried by insects on to the surface of the young fruit, or not 

 infrequently the flowers are also inoculated from spores derived 

 from young leaves ; and in many instances where brown and 

 shrivelled blossoms are attributed to the action of a late frost, 

 the true cause is in reality due to the Monilia fungus. 



In those instances where the disease has been allowed to 

 follow its course undisturbed for some years, the young shoots 

 of the trees are also attacked and killed during the first or 

 second year. The fungus develops rapidly on such dead twigs, 

 and furnishes a ready supply of spores, which are mature during 

 April and May, just when the young leaves and blossom are 

 most susceptible, and wholesale infection results. 



Fruit attacked by this disease does not rot and decay, but 

 becomes dry and mummified. Such fruit often remains hanging 

 on the tree until the following season. Whether it does so or 

 falls to the ground, it is practically unchanged until the follow- 

 ing spring, when its entire surface becomes covered with a 



