122 MASSACHUSETTS HORTICULTURAL SOCIETY. 



(hiring warm spells in winter, causing the formation of poison 

 which when circulation set up in the spring was carried to the 

 growing twigs ami blossoms. He said further that a neighbor near 

 him who had a large orchard made a ])ractice of hauling ice into his 

 orchard and distributing it about among the trees during warm 

 spells in late winter to keep the temperature of the trees down. It 

 may interest you to know that no less a personage then Henry 

 Ward Beecher was an advocate of the "frozen sap" theory. 



The discovery by Dr. Burrill of the bacteria in the diseased tissues 

 of blighted twigs and the subsequent careful inoculation experiments 

 by Dr. Arthur established beyond a doubt the true cause of the 

 disease. Since that time much has been done by various workers 

 to find a remedy for this most destructive malady. By far the 

 greater part and most successful of this work has been done by Mr. 

 M. B. Waite of the U. S. Dept. of Agriculture. He has in the last 

 ten years carried on numerous and extensive experiments in the east- 

 ern and central part of the United States in the control of this disease 

 by extermination. He is at present I believe directing extensive 

 experiments in the control of the blight in California where the 

 disease has made its appearance only in the last few years but with 

 such destructive effects as to dismay the pear growers of that section. 



The symptoms of the disease are so well know^n to all fruit 

 growers that it scarcely seems necessary to detail them here. To 

 the grower the first evidence of trouble in his trees is the apparent 

 sudden blackening of the blossoms or the leaves on the end of 

 twigs or spurs. Frequently the disease has extended for a consider- 

 able distance down the limb before it is noticed. 



"We will now take up what I may call the "annual history of the 

 disease." We will begin with its appearance on the flowers in the 

 spring causing what is popularly known as "blossom blight." The 

 bacteria are introduced into the opening blossoms chiefly by bees. 

 From whence the bees get the bacteria will be explained presently. 

 Since practically all the blossoms on a tree are visited by bees it 

 frequently happens that the percentage of blighted fruit spurs is 

 very large. This is usually the first form of the disease to appear 

 in an orchard that is in bearing. Apple growers have frequently 

 observed that only those trees or limbs of trees that blossom suffer 

 from the blight. The explanation as we have seen is simple. 



