346 PEAR GROWING IN CALIFORNIA. 



areas of bark. During the winter season when holdover blight is 

 present its detection is often very difficult and requires the closest 

 searehinu-. It is also somewhat difficult, in fact sometimes impossible, 

 to tell whether or not certain dead areas are due to blight. The prob- 

 lem of removing all holdover being of such importance, it is not safe 

 to take any chances on leaving any suspicious areas of bark that are 

 found during the dormant season, consequently all doubtful cases 

 should be treated as pear blight. 



Destructiveness. 



"It is an ill wind that blows no one good,'' is an old, trite saying 

 which finds application in the case of pear blight infection of our 

 orchards, for what has meant destruction of business to many, has 

 meant to others the adoption of proper methods of control, high 

 prices for the fruit, and financial success. That the production of 

 pears has been limited to a remarkable degree by the worst of all 

 pear diseases is a fact well known to every student of the pear industry 

 throughout the nation. Whether or not this has favored the industry 

 in California, we know that despite the blight many of our growers 

 are doing remarkably well. With the tremendous production that 

 would result were the blight eliminated so that every one could grow 

 pears, it is doubtful if prices would be so good and the business on as 

 firm a footing as today, and the California pear grower, who considers 

 that blight is the greatest menace to the industry, may be harboring a 

 friend in diguise. Were the disease impossible to control an entirely 

 different light would be thrown on the situation. 



In blighted orchards that have been neglected, the loss of trees will 

 vary according to conditions which may be favorable or unfavorable 

 for its development. Many orchards in California have been destroyed 

 outright in a few years' time. More often the process of destruction 

 is slow and each season a few trees die from the attack. Even in 

 orchards where the greatest care is exercised in an attempt to eradicate 

 blight it is quite common to lose a tree now and then. The destructive- 

 ness of this disease under conditions that favor its development can be 

 attested by many a San Joaquin Valley orchardist, who some years ago 

 attempted to grow pears in one of the counties of this valley and who 

 lost everything because of the virulence of the disease under the 

 existing conditions. 



Holdover Blight, 



This term is used to designate the stage of the disease which is 

 present in trees during the dormant season and which serves as a 

 starting point for infection during the season of active growth. Hold- 

 over cankers are common in any orchard where blight occurs and 

 where nothing has been done toward its eradication, and even in 

 orchards where the greatest of care has been exercised in control v/ork 

 some cankers will escape the eyes of the most careful blight cutters and 

 will remain as a menace to the health and life of the other trees. 

 These cankers may occur on any part of the tree, and often are impossi- 

 ble to detect in large roughened trunks by a casual examination of the 

 tree. The plan, therefore, adopted by up-to-date blight cutters is to 



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