16 



TlIK [OL'RXAL OI' Ill-KKDITV 



to quarantine against the bark disease 

 on chestnut nursery stock, and they 

 should now take special care that no 

 shipment, however small, escapes their 

 rigid inspection. 



A. PRACTICAL DIFFICULTY. 



The most serious practical difiiculty 

 in inspecting nursery stock for this, as 

 for other fungous diseases, lies in the 

 fact that virtually all State inspectors 

 arc entomologists and are usually not 

 trained in recognizing the more ol^scure 

 symptoms of fungous disease. Nursery 

 trees affected by the bark disease rarely 

 show it prominently at the time when 

 they are shipped ; the threads of conidia 

 or the yellow or orange pustules are 

 rarely present, and usually all the in- 

 spector can find is a small, slightly 

 depressed, dark-colored area of dead 

 bark, usually near the ground, which is 

 easily overlooked or mistaken for some 

 insignificant injury. Upon cutting into 

 such a spot the inner bark shows 

 a most characteristic, disorganized, 

 "punky" appearance and characteristic 

 "fans" of the yellow mycelium of the 

 fungus. Occasionally a very characteris- 

 tic yellowish brown or reddish band or 

 blotch, either girdling or partly girdling 

 the young tree, may be seen. 



If infected trees are set out they 

 develop the disease with its characteris- 

 tic symptoms the following spring. On 

 account of their small size such trees are 

 girdled and die before the end of the 

 summer. Meanwhile they become a 

 source of danger to neighboring orchard 

 and forest trees. Orchardists and nur- 

 serymen purchasing chestnut trees arc 

 therefore urged to watch them closely 

 during the first season, no matter how 

 rigidly they may have been inspected. 



In view of the uncertain future of the 

 chestnut tree the ])lanting of chestnuts 

 anywhere cast of Indiana, at least for 

 the i^resent. can hardly be advised. 

 West of the natural range of the Ameri- 

 can chestnvit, however, the situation is 

 quite different. Obviously the western 

 chestnut orchardist has before him a 

 great opjDortunity. No matter how 

 successful efforts to limit the bark 

 disease may be, the nut crop will be 

 reduced for some vears, and the business 



of growing fine orchard chestnuts in 

 the East will be depressed for the same 

 length of time. There is no apparent 

 reason wliy, with rigid inspection of 

 purchased stock and of the orchards 

 themseh'cs, all chestnut orchards and 

 nurseries from Indiana to the Pacific 

 coast can not be kept permanently free 

 from the bark disease; therefore, all 

 persons interested in growing the chest- 

 nut in the West are earnestly advised to 

 be sure that stock from any source is 

 rigidly insjjected, to watch continually 

 and with the utmost care their own 

 nurseries and orchards, and to dcstro}' 

 immediately by fire any trees that may 

 be found diseased. The discovery of 

 an infected orchard in British Columbia 

 indicates that other chestnut orchards 

 will probably be found on the Pacific 

 coast which have become infected by 

 direct importation from the Orient. 



BREEDING NECESSARY. 



Probably the most ]:)ractical control 

 results in the long run will be obtained by 

 the breeding and propagation of varieties 

 of chestnut that arc immune or highly 

 resistant to the bark disease. Else- 

 where in this magazine Dr. W. \"an 

 Fleet has described his work in this 

 line. It appears that so far no immune 

 or even resistant individuals of the 

 American chestnut have been found, in 

 spite of strenuous search; so that we 

 must largely dei)end on the Asiatic 

 varieties. The slight resistance of the 

 chinquapin, as observed in the field, 

 may be due only to its comparative 

 freedom from bark insects. The si)ecics 

 of Chinese chestnut u])on which the 

 disease occurs in China (fig. 1) is ap- 

 ])arently resistant to the disease in 

 that climate, but it remains to be seen 

 to what extent this resistance will 

 persist when the trees arc grown in 

 America. The Japanese chestnut is 

 highly resistant, and certain strains 

 aijparenlly immune; these strains fonn 

 at ])resent the most ho])eful basis for 

 breeding. At ])resent we do not know 

 exactly what the Japanese chestnut is; 

 most of the trees that pass under this 

 name in the American market a])i)ear to 

 be hybrids with the American or other 

 varieties. 



