FOREST INSECTS AND FUNGI II9 



done on Long Island, and in the vicinity of New York City, 

 from which as a center it is spreading. Only since 1905 has 

 the disease been generally recognized, and in New England it 

 was little noticed until 1907. Southwestern Connecticut is the 

 most seriously infected region here; and in Fairfield County the 

 chestnut has been nearly all killed. As we proceed from south- 

 western Connecticut, through that state and then into Massa- 

 chusetts and northern New England, the number of infected 

 trees is less and less noticeable. But the disease may be found 

 practically over the entire New England range of the species. 

 North of Connecticut no great amount of timber has as yet 

 been killed. 



The chestnut bark disease attacks and kills the cambium 

 layer, which lies between the bark and the wood. This is the 

 growing layer of the tree and when it is girdled, death of the 

 portion above the injured place results. As the disease is 

 distributed by the spores (virtually seeds) which are easily 

 blown by winds, or carried by birds, its spread is rapid. These 

 spores cannot attack a tree except through a wound, but as 

 every tree has many slight wounds or openings in its bark, it 

 is rarely that a tree is exempt from the disease. When a spore 

 finds lodgment it quickly develops a fungous growth spreading 

 in the cambium layer at first in a somewhat elliptical form until 

 finally it girdles the branch or trunk. It may also work up and 

 down the trunk. 



Trees of all ages from the young sprout to those of lumber 

 value are attacked. In an old tree with thick bark the disease 

 usually enters at the top and works downward. On young trees, 

 with easily wounded bark, the disease may start at any point. 

 When old trees are injured by fire, even to a very slight extent, 

 the disease will find entrance at the base. 



There are several ways in which the work of this fungus can 

 be recognized. The spots or cankers are apt to have an ellip- 

 tical form, and the bark over the injured part is somewhat 

 reddish and sometimes appears sunken. Pustules, of a yellow- 

 ish or orange color, containing the spores can often be seen pro- 



