CONNECTICUT EXPERIMENT STATION REPORT, 1909-1910. 



beetle had not been at work. The most serious injury seemed 

 to occur in the vicinity of Chapinville. At the request of Mr. 

 Walter Angus, manager of the Scoville estate at that place, Mr. 

 Walden first visited there in August, and as he found no insect 

 responsible for the trouble the writer made an investigation 

 early in September to determine if a fungus was the cause of 

 it. By July, or earlier, some of the trees had almost entirely 

 shed their leaves, and later put forth a new crop, and these, 

 when examined by the writer, were quite free from fungous 

 attack. Other trees, however* not originally so severely injured, 

 showed the leaves quite badly infected with the above fungus, 

 and these had been shedding their leaves more or less during 

 the season. Where the defoliation had been rather severe, the 

 young branchlets of the season had also frequently fallen off. 

 While the fungus was present on some trees more than on 

 others, and while some of the fallen leaves showed no sign of 

 the fungus, it seemed quite evident, after a careful examination, 

 that this fungus was primarily responsible for the trouble, but 

 that drought had helped to exaggerate it. The illustration shows 

 the condition as regards foliage of one of the trees photo- 

 graphed by Mr. Walden in August. 



The fungus produces very numerous, small, black eruptions 

 on the upper surface of the leaves, and these often merge more 

 or less in small groups. In time the specimens show a whitish 

 or grayish margin around these black cushions, due to the 

 wearing away of the epidermis. We have been unable to find 

 any fruiting stage in any of the specimens we have gathered 

 in different years, as the only known stage produces its asco- 

 spores on the fallen leaves the subsequent spring. Infection 

 seems to take place only early in the season, since the trees 

 early denuded did not have their second crop of leaves attacked 

 to any extent. Apparently the weather conditions in the spring 

 determine the character and amount of infection, and these 

 conditions seem to have been unusually favorable in 1909. In 

 1910, on the same estate in Chapinville, the fungus did practi- 

 cally no harm, though the trees bore a smaller crop of leaves, 

 due to the shedding of the small twigs the previous year and 

 to the death of others that were severely injured. 



Spraying the unfolding leaves with Bordeaux would probably 

 control this trouble, though the uncertainty of its appearance 

 would make such a treatment rarely practical. 



