226 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 5 



10 Farmers' Bulletin 467, "The Control of the Chestnut Bark Disease," 

 and to future publications of the Chestnut Tree Blight Commission 

 of Pennsylvania. Perhaps the feature of control of most interest to 

 Horticultural Inspectors is the inspection of diseased chestnut nursery- 

 stock. 



As has been indicated, such stock has in the past been a most impor- 

 tant factor in the spread of the bark disease. On account of a well- 

 grounded fear of this disease much less chestnut nursery stock is 

 being moved now than formerly, but there is still enough to constitute 

 a serious source of danger. It is therefore obvious that every state 

 in which the chestnut grows, either naturally or under cultivation, 

 should as speedily as possible pass a law putting the chestnut bark' 

 disease on the same footing as other pernicious diseases and insect 

 pests, such as peach yellows and the San Jose scale, against which 

 quarantine measures are taken. Many inspectors already have 

 legal power to quarantine against the bark disease on chestnut nursery 

 stock, and they should now take special care that no shipment, how- 

 ever small, escapes their rigid inspection. 



The most serious practical difficulty in inspecting nursery stock 

 for this as for other fungous diseases lies in the fact that practically 

 all state inspectors are necessarily entomologists, and are not trained 

 in recognizing the more obscure symptoms of fungous diseases. Nurs- 

 ery trees affected by the bark disease rarely show it prominently at 

 the time when shipped; the threads of summer spores or the yellow 

 or orange pustules are rarely present, and usually all the inspector 

 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 disorganiz;ed "punky" appearance, 

 quite different from that of any other bark injury; but it is impossible 

 to adequately describe this appearance without recourse to colored 

 illustrations. Occasionally a yellowish-brown band, either girdling 

 or partly girdling the young tree, may be seen; this is very character- 

 istic, but is so prominent a symptom that it may be noticed at the 

 nursery, and presumably trees so affected will not be shipped. 



If infected trees are set out they develop the disease with its char- 

 acteristic symptoms the following spring. But on account of their 

 small size such trees are girdled and die before the end of the summer, 

 often in two or three weeks. Meanwhile they are spreading the 

 disease to neighboring orchard and forest trees. Orchardists and 

 nurserymen purchasing chestnut trees should therefore be warned to 

 watch them closely during the first season, no matter how rigidly they 

 may have been inspected. 



