40 



is the appearance of numerous small brownish red pustules over the 

 surface of the canker. These are the fruiting bodies of the fungus. 

 (Specimens of bark showing these bodies were passed for examination). 



This fungus owes its destructiveness to the facts that (1) It is a 

 rapid grower, girdling large branches in a few months and killing 

 good sized trees within two years^ (2) It produces enormous numbers 

 of spores or seeds within a short time, after the cankers are formed. 

 These are of two kinds but both are exfremely resistant to cold and 

 drying and consequently are able to spread the disease with astonishing 

 speed. In fact, there seems to be no weak point in the entire life history 

 of this fungus and for this reason we should be very careful to keep 

 it out of our commercial chestnut orchards. 



Control of chestnut bligJit: The control of chestnut blight in 

 commercial orchards is comparative!}^ simple in spite of the failure 

 to control it in the forests. The reason for this is that in an orchard 

 the individual tree is of much greater importance than in the forest 

 and greater pains can be taken to eliminate the disease. Of course, 

 if one jjlans to plant a chestnut orchard it would be very unwise to 

 select a location where the native chestnut occurs. The chestnut does 

 well in many localities outside its natural ran,g'e. There is little 

 danger of the disease being introduced into plantations outside the 

 area of the natural chestnut growth, provided one is reasonably care- 

 ful to avoid securing nursery stoek of any kind or other plant ma- 

 terials from the blight region. Should any trees show cankers, prompt 

 and careful cutting out of the cankers will eliminate the disease. 

 Prompt and thorough work is necessary. I will not attempt to des- 

 cribe the method of cutting out cankers since this procedure is familiar 

 to most of you biit should you desire further information along this 

 line I shall be glad to furnish it. 



The fact that the native chestnut is being exterminated is to tlie 

 advantage of the commercial grower of the better chestnut varieties 

 since he can obtain a better market and be sure of increasing demands 

 in the future. 



There is a possibility in developing blight resistant hybrids by 

 crossing our chestnuts with pure strains of Japanese and Chinese 

 chestnuts. As many of you know tlie blight fungus was found to 

 have been imported from China where it seems to do little damage on 

 the native chestnuts. Most hybrids have proved susceptible to blight 



