MICHiaAN ACADEMY OF SCIENCE. 131 



very low, and tlio extent of damage from this disease is sometimes 

 the deciding factor as to whether a bed is profitable or not. 



TREE DISEASES. 



Chestmit Bark Disease. The finding of the Chestnut Bark dis- 

 ease in Tainesville, Ohio, and its occurrence in several western 

 states made the question of whether the disease had advanced into 

 Michigan of some interest. Chestnut as a forest tree is found only 

 in a very restricted area in Michigan, in fact its occurrence is 

 practically limited to two counties, Wayne and Monroe, in the 

 southeastern part of the state. 



In 1912, the report reached the department that many trees 

 were dying about Wayne. Upon investigation at Wayne and Belle- 

 ville no trace of the disease could be found in the large groves 

 around those places. The death of tops and the general unthrifty 

 condition was caused by the ravages of a cyclone. In 1914, in 

 company with Mr. M. W. Gardner these localities were again visited 

 and the groves carefully examined. In addition many large 

 acreages of native chestnut about Monroe were inspected. No case 

 of the disease was found. 



The Chestnut plantations at the college have shown a marked 

 mortality for the last few years, but on the dead trees no lesions 

 of the Chestnut Bark disease have been found. Dr. Beal who 

 planted nearly all of tlie trees and who has watched their growth 

 for years attributes the death of the trees to severe winters. 



Maple Leaf Diseases. Each year the college receives numerous 

 specimens of hard maple leaves which show dead areas. Depending 

 upon the time of year, or in other words, upon weather conditions, 

 these specimens are either anthracnose resulting from the attack of a 

 Gloeosporium or the well-known Leaf Scorch due to drought. The 

 dead areas (PI. IX) run along an affected vein in specimens which 

 are sent in in spring and early summer, while those sent in in 

 August show the dead areas between the veins. In the former 

 case fruiting bodies are not readily found on the specimens, but 

 they devehip readily in moist chamber after a few days. The other 

 specimens may mold, but no sign of anthracnose-like fungi are 

 found. 



These two diseases are of importance in Michigan where the hard 

 maple is the principal shade tree in some cities, not so much because 

 of the damage or even the unsightly a])pearance of the trees, but be- 

 cause of the number of trees that are cut down bv the owners. The 



