CHAPTER XV. 



SPREADING OF DISEASE AND EPIDEMICS. 



Dissemination of fungi by tJie aid of snails, rabbits, bees, 

 and insects Man Distribution in soil, on clothes, 

 through the post, etc. Worms, wind^Puffing of 

 spores Creeping of mycelia Lurking parasites 

 Spread of i)tsects a?td other animals Losses due to 

 epidefnics. 



The dissemination of plant diseases is a subject 

 which has been far too much neglected, but our 

 knowledge of it is slowly increasing. The spores 

 of fungi such as Rusts and Erysipheae are often 

 carrried from plant to plant by snails ; those of 

 root-destroying and tree-killing Polyporei by 

 rabbits, rats, and other mammals which rub their 

 fur against the hymenophores. Bees have been 

 shown to carry the spores of Sclerotinia and infect 

 the stigmas of Bilberries, etc., with them ; and flies 

 convey the conidia of Ergot from grain to grain. 

 Insects, indeed, of all kinds are great disseminators 

 of disease as witness also the part played by 



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