52 Forest Club Annual 



holes they make through which the spores may enter. Aside from 

 the question of the dissemination of the spores by these insects, 

 there is no doubt but that the presence of their galleries in the 

 trees, bringing in more than the normal amount of air found un- 

 der the bark, materially aid the growth of the fungus. Abundant 

 evidence of insect association, principally beetle and other large 

 insect larvae, pupae and galleries, were found at Bala, Pa. Fully 

 nine-tenths of all old lesions showed beetle larvae, mainly Lep- 

 tura nitons, in or near them. Larvae were found in about two- 

 fifths of the younger lesions. In all cases there were about twice 

 as many larvae in as near the lesions which would indicate that 

 these insects usually follow rather than precede the infection. 



Craighead (5) reports some interesting observations on the 

 relation of insects to the chestnut bark disease. The most strik- 

 ing theory advanced is that certain insects contribute to the nat- 

 ural control of the disease by feeding on and at the same time 

 destroying the fruiting bodies. The author states that he observ- 

 ed the larvae of a Cerambycid, Leptostylus macula Say, and a 

 Colydid, Synchita fulginosa Melsh, while caged, to eat the pus- 

 tules and stroma, the latter even to eat the conidial threads. A 

 series of cultures of the stomach contents and excrement of L. 

 macula were made. The spores did not germinate in a single 

 case. Both pycnidia and perithecia are eaten cleanly and deeply 

 into the bark by the insects. While L. macula appeared to be 

 doing most of the work, Agrilus bilineatus Web, Bassareus prc- 

 tlosus Melsh, and Th\ mains fulgidus Er. were found to eat the 

 pustules. These insects cannot, however, play an important role 

 in controlling the disease, for if an insect eats the spores it must 

 get them on its body and in this way aid more in the dissemination 

 of the disease than in its control. 



The theory has often been advanced that birds are a factor 

 in the spread of the disease over long distances. They are possi- 

 bly also effective in spreading the disease locally from tree to 

 tree by carrying the spores on their feet and bills from infected 

 branches to those that are healthy. Woodpeckers, nuthatches, 

 flickers, and other birds, which bore into the bark for insects, 

 were observed visiting cankers of the blight. During the autumn 

 and early winter of 1911-12, a detailed study of an advance area 

 of infection was made in central Pennsylvania. The tract cov- 

 ered some forty-six acres on the north and northwest slope of a 

 mountain. Most of the chestnut growth was coppice four years 

 of age. Altogether three thousand fifty-nine chestnut trees, 

 sprouts and stumps were examined and two hundred eighty, or 

 9.1 per cent, were found to be infected. Woodpecker work was 



