ii6 



THE CANADIAN HORTICULTURIST. 



applied the name " frozen sap blight " to the 

 disease. His theory was that the disease 

 was due to the freezing and thawing of the 

 sap. The sap thus lost its vitality, became 

 dark and discolored and poisonous to the 

 plant. 



Thomas Meehan, editor of the " Garden- 

 ers' Monthly," supported the idea that fungi 

 was the cause of the disease ; but no tests 

 were applied to prove that the inoculation 

 of these fungi into healthy trees would 

 cause the disease. 



It was not until the year 1878, when. W. 

 T. Burrill, the professor of botany in the 

 University of Illinois, announced to the 

 State Horticultural Society the discovery of 

 bacteria, apparently connected with the dis- 

 ease. Burrill also proved that the disease 

 was infectious and could be communicated 

 to healthy limbs, by inoculation, using the 

 gummy exudation from an affected tree as 

 a virus. Not only was he able to produce 

 the disease in pears, but also in apples and 

 quinces. Dr. J. C. Arthur, botanist of the 

 New York Experiment Station, subse- 

 quently confirmed Prof. Burrill's results and 

 thoroughly established the fact that a cer- 

 tain species of micro-organism, named by 

 the discoverer Bacterium amylovorum, or 

 the starch destroying bacterium, was the 

 sole cause of the disease. 



Geographical Distribution. — This dis- 

 ease is peculiar to North America. So far 

 it has never been recognized in Europe. 

 Professor Budd, of Iowa, who is familiar 

 with the disease as it occurs in North Am- 

 erica, has inspected the orchards of Europe 

 and states that no trace of fire blight of pear 

 or apple trees can be seen in Europe. It 

 is also unknown in New Zealand and Aus- 

 tralia. In North America the blight ex- 

 tends from New York to California, and 

 from the northern counties of Ontario to 

 Texas. Dr. Beadle, in a sketch of the his- 

 tory of the disease in Ontario, states that 

 " in the early days of fruit growing in the 



Niagara district we had no pear tree blight 

 nor apple blight. With the advent of what 

 people termed grafted fruit there came, after 

 a few years, 'blight ' on the pear tree." By 

 the year 1840 it had spread considerably. 



N. J. Clinton, of Essex County ; S. Hun- 

 ter, of Oxford; E. D. Smith, of Went- 

 worth ; Stone and Wellington, of Welland ; 

 R. Hamilton, of Argenteuil, reported its 

 presence in their respective counties about 

 35 years ago. The colder parts of the pro- 

 vince have suffered as severely from the 

 disease as the more favored districts. The 

 orchard of the Dominion Experimental 

 Farm at Ottawa has been attacked, and the 

 140 Russian varieties of apples cultivated 

 there have suffered severely. In warmer 

 districts, however, the disease has been 

 much more severe. Whole orchards have 

 been completely destroyed in the State of 

 Texas, and certain pear growing districts 

 in that State have been practically ruined by 

 this parasite. 



Losses. — No statistics are available to^ 

 give us an idea as to the amount of loss to 

 fruit growers from pear blight, but a few 

 references to losses by this destructive dis- 

 ease will help to give us an appreciation of 

 the subject. Coxe in 18 17 reported that 

 he had lost upwards of fifty trees in twenty 

 years. In the years 1826, 1832 and 1844 

 there was an increased prevalence of the 

 disease, and few pear orchards escaped 

 without partial or total loss of many trees, 

 and some orchards were quite destroyed. 

 Downing called it the " monstrous malady 

 of the pear." Lyons stated, as the opinion 

 of many cultivators in the State of Michi- 

 gan, that " the pear tree cannot be grown 

 with financial success on account of the 

 blight." Hallam, in 1882, reported that 

 " in Southern Illinois pears have failed, ut- 

 terly failed, so that none are now cultivated 

 for market. The blight has destroyed the 

 trees, branch and root." While A. Noice, 

 of the same State, doubted " if one-tenth of 



