Fire Blight of Pears, Apples, Quinces, Etc. 



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fined to the regions east of the Rocky mountains, but in 1903, despite 

 the claims of the exploiters of the fruit regions of California, that their's 

 was a country in which the Blight could not thrive, it suddenly made 

 its appearance in the pear orchards of that State and wrought such 

 havoc in a few years as has seldom been known in a fruit-growing 

 country. 



Distribution. This disease, which is without doubt of American 

 origin, is now known throughout the United States and Canada in 

 nearly every section where 

 fruit is grown. It is, how- 

 ever, confined to North 

 America. It is not certainly 

 known to occur in any of the 

 countries of Europe or in 

 South America or Australia, 

 although there has been 

 more or less chance of in- 

 troducing it through stock 

 imported from this country. 

 Whether its restriction to 

 this continent is to be attrib- 

 uted to the special vigilance 

 of those who have imported 

 fruit trees from America or 

 to the habit of the parasite in 

 passing the winter alive, usu- 

 ally only in cankers on rela- 

 tively large trees (Fig. 10), 

 is not certain. We are in- 

 clined to regard the latter 

 as the more probable ex- 

 planation. 



Economic importance. This is the most destructive and the most 

 dreaded disease of fruit trees, particularly of the pear. It is of a dis- 

 tinctly epidemic nature, appearing suddenly in virulent form in a 

 locality, often wiping out entire orchards or injuring the trees so severely 

 that several years are required for recovery from the effects of the 

 attack (Fig. 11). It may not again appear to a destructive extent in 

 the same locality for ten or fifteen years. Nevertheless it is to be found 

 every season to a limited extent in any locality, ready when the proper 

 combination of conditions arises to spread rapidly and again work havoc. 



Fig. 1 1 . — After the pruning made necessary by 

 one season of the unchecked ravages of the 

 Blight, in old Bartlett Pear trees. 



