UNITED STATES DEPARTMENT OF AGRICULTURE 



BUREAU OF PLANT INDUSTRY 



Amiierst, TTass, 



PATHOLOGY Fstruarj 9, 1926 



Ilr. "/alter Deane, 

 29 Brewster Street, 

 Cambridge, UaBS, 



Eear Sir: 



The future of the eastern white pine and chestnut, two of the most 

 valuatle timber trees of the Northeast, is serioucly threatened by introduced 

 fungous diseases. In the last twenty-five years our extensive and valuable 

 chestnut forests have been killed by the fungus ENCOTHIA PARASITICA which came 

 to us from China. The chestnut, as a timber tree, has disappeared from its 

 northernmost range to western Pennsylvania and Virginia and is being extermi- 

 nated from there southward. Such complete destruction of an important timber 

 tree by a parasitic fungus has never been previously known by man. It brings 

 us to the serious consideration of means of replacing the chestnut with some 

 resistant timber tree if possible. The breeding of races of short-lived field 

 crops resistant to destructive fungous diseases has been accomplished suc- 

 cessfully. Races of cotton, watermelon and cowpea have been bred which resist 

 wilt so successfully as to yield good crops on land which is infected so thor- 

 cughly that the unselected races of these crops are entirely useless. It is 

 well known to plant pathologists that in areas where a crop plant is ruined 

 by fungous disease outbreaks, there usually are a few resistant plants which 

 manage to survive and in some instances may even approach normal vigor of 

 growth. Such resistant individuals may serve as a basis for selection and 

 breeding for greater resistance. There is no apparent reason why this should 

 rot hafpen with our chestnut also, but it will take many more years to prove it 

 with a long-lived tree than in the case of the short-lived field crops. A 

 leginning has been made in the treeding of resistant chestnut trees which may 

 serve for the production of nuts of satisfactory size and quality. But no re- 

 sistant tree has yet been found which has the size needed to produce timber. 



An effort is being made to find any tree of our native chestnut which 

 may be resistant to the blight. Many such suspected cases are under observa- 

 tion already. A tree to be considered resistant must have had the blight present 

 in its vicinity at least ten years and preferably longer. It should have a 

 considerable portion of its top and branches still alive, and should show evi- 

 dence of having had the blight on large branches or trunk for five to ten years. 

 It appears to be too much to expect to find a tree which is completely immune 

 to the disease. If all observers who have a chance would keep this matter in 

 mind and report the exact location and size of chestnut trees which seem to be 



