FORTY-THIRD ANNUAL REPORT. 67 



the maturing of the next year's fruit-buds is manufactured by the leaves 

 after the present crop is picked, so it is evident "that if the majority of 

 the leaves fall to the ground, the tree and the future crop will suffer. 



For many years, it was not definitely known how this fungous passed 

 the winter, and most peo])le surmised that it either stayed in the twigs 

 or else Avintered over in the old dry leaves. Last year, B. B. Higgins, 

 of the Cornell Experiment Station, discovered the winter stage of this 

 fungous and proved to his own satisfaction that tjie disease winters over 

 in the old leaves. On account of his discovery, the name of the fungous 

 will probably be changed from C ylindrosporium padi to Coccoinyces 

 heinialifi. 



The disease first shows up as discolored spots on the leaves, which 

 gradually enlarge. Later they become dark around the edges of the 

 circular patches and pale in the centers. These spots wither, dry up, 

 and fall out, leaving round, clean-cut holes, Avhicli resemble those caused 

 by shot, hence the name "Shot-Hole Fungous." 



When the disease has Aveakened the leaves sufficiently, they fall to the 

 ground and dry up. There is a slow development of the fungous dur- 

 ing the winter and the mature spores come out in the spring about May. 

 These small spores are then blown about by the wind and fall on the 

 young leaves of the cherry trees, producing new infections. 



In controlling this disease, our work must be preventative rather than 

 curative. We must have every part of the leaf-surface of the trees cov- 

 ered with spray, so that when the spores fall on the young leaves and 

 start to germinate, the little germ-tube will come in contact with the 

 caustic spray and be killed immediately. We must kill these spores be- 

 fore they get into the leaf-tissue for after they have gained entrance, 

 we cannot affect them by spraying and they will spread the disease 

 rapidly. 



When we spray, we should have plenty of pressure so that we can 

 throw the solution in a very fine mist, being careful to cover all parts 

 of tlie trees, for if some places are overlooked, the spores Avill be sure to 

 find them and there reproduce themselves. 



Formerly it was the custom to spray with Bordeaux Mixture for this 

 disease, but the Horticultural Department of the Michigan Agricultural 

 College, carried on experiments using dilute lime and sulphur (1 to 40) 

 instead, and found th.at it controlled the fungous perfectly and caused 

 no burning of the foliage. Many people have been afraid to use lime and 

 sulphur because they understand that it would burn the leaves, but Prof. 

 White proved by his experiments, that if it was properly applied, no 

 damage v.ould result. 



Since this fungous winters over on the old leaves of the 

 past season, general clean-up measures and the burning of the 

 leaves are beneficial and destroy the source of much of the trouble. Now 

 if we do all we can to destroy the old leaves by early plowing in the 

 spring, etc., which winter this fungous over, and then do a thorough job 

 of spraying at the right time so that we prevent the spores from germ- 

 inating, we surely will have the disease under control. 



