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were obtained from afifected chestnut twigs in November and 

 cultivated on various nutrient media until early in the spring, 

 when inoculations were made into several young chestnut trees 

 in the propagating houses ; on all of which the disease has 

 appeared in its normal condition during the present season and 

 fruited abundantly. All of the twigs inoculated have died, the 

 others remaining perfectly healthy. All attempts to introduce 

 the fungus into a tree without an abrasion of the surface of the 

 twig have failed. 



The fungus enters through a wound or dead limb and works 

 beneath the cortex in the layers of the inner bark and cambium. 

 The bark soon dies and changes color and later becomes rough 

 and warty from the presence of numerous yellowish-brown fruit- 

 ing pustules, which appear in the lenticels and send out peculiar 

 twisted spore-masses containing millions of minute summer 

 spores. These spores are produced continuously throughout 

 the summer and early autumn and germinate without a period 

 of rest when they fall upon wounds in other chestnut trees. 



The winter spores mature in late autumn in the same pustules 

 and germinate the following spring, when the mycelium which 

 has passed the winter in the infected branch also begins to grow 

 again and continues to spread beneath the cortex, sending up 

 fruiting pustules and distributing spores as in the previous season. 



The fungus attacks twigs, branches and trunks of chestnut 

 trees, irrespective of size or position, and usually proceeds in a 

 circle about the affected portion until it is completely girdled. 

 The death of the end of a branch necessarily causes loss of 

 vitality and partial death to the remainder, and this enables the 

 fungus to spread very rapidly through the tissues below until 

 it reaches the main trunk, when the life of the tree is measured 

 by a few years at best. 



The mycelium of the fungus is unfortunately so active and so 

 well protected that no treatment can be suggested except the 

 rigorous use of the pruning knife ; and this has many limitations. 

 Spraying solutions will not avail, since they do not reach the 

 fungus and cannot possibly kill the countless numbers of spores 

 continually produced ; nor will they protect the surface from 



