i9o8] EDGERTON—ANTHRACNOSES ' 377 



This stage is extremely fatal to young sycamore trees. A careful 

 search was made for young trees that could be transplanted for inocu- 

 lation purposes, but they were found to be very scarce. When some 

 were found, however, the reason for their scarcity was evident; they 

 were being killed by the anthracnose. The young trees had the same 

 appearance as the terminal twigs on the larger trees; the leaves were 

 nearly all killed when they were about one-quarter grown, and the 

 young shoots were covered with Myxosporium pustules (fig. i) . The 

 tree on the left in the figure was in the condition of most of the seed- 

 lings. Only after careful search was a young tree found that was 

 nearly healthy and could be photographed for comparison; and an 

 examination of the photograph shows that a few leaves are dead on 

 this one. If the time ever comes when this tree is planted for com- 

 mercial purposes, this disease may develop into a very serious pest in 

 the nursery. 



How the fungus enters the twigs was not satisfactorily determined. 

 There are two possibilities; it may pass down the diseased petioles 

 into the twigs, or the twigs may become infected directly from spores. 

 The twigs are infected very close to the apical bud. The presence of 

 the disease on the petioles and the lack of any wounds of any kind on 

 the twigs make it seem possible at least that the former indicates 

 the real method of infection. 



Also the question of the fresh infection of the leaves in the spring 

 is not entirely settled. Inoculation experiments tried on leaves in the 

 laboratory were without success. Perhaps the period of incubation 

 is too long to attempt inoculations on branches cut from the tree and 

 kept fresh by standing in water. However, it was useless to attempt 

 inoculations out of doors where nearly every tree was aheady infected. 

 Several investigators have attempted to infect the leaves artificially, 

 but mostly without success. Klebahn after making a large number 

 of inoculations obtained a few successful ones; but one of his checks 

 also took the disease. 



The J^Iyxosporium stage undoubtedly plays the larger part m 

 causing the spring infection of the disease. WTiHe the spores, both 

 conidial and ascigeral, are borne in abundance when the leaves are on 

 the ground, they are held together by a mucilaginous substance aiid 

 are not carried by the wind. The Myxosporium spores on the t^'igs 



