PKAR GROWING IN CALIFORNIA. 



285 



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fratiii.u: standnrd trees, and possesses certain merits which will iindoul)t- 

 edly make it more po])nlar than the French species in the future, unless 

 some undesirable eharacteristics, Avhicli at present are not known, 

 should develop. In addition to Pifrus serotina, there are a number of 

 other species grown in China and Japan, some of which are mentioned 

 in connection with the discussion of varieties and species resistant to 

 pear blijxht. The Frcncli stock has a tendency to produce an abundance 



Fig. 101. Larse leaf from Japane.se seedling, Pyrus serotina; 

 small leaf from French seedling, Pyrus communis, showing the 

 characteristic siiape and serration. 



of water sprouts, which often completely surround a tree in a dense 

 thicket-like mass. This unfavorable characteristic, Avhich is not possessed 

 by the Asiatic or commonly called Japanese stock, that has been used 

 for propagation in this country, has a direct bearing on the worst dis- 

 ease of the pear, viz: blight, as the growth coming directly from the 

 roots. often becomes infested with aphis, thrips, or other insects or mites 

 and the disease is carried into the root system, where control is exceed- 

 ingly difficult and expensive and eradication is scared}' possible. In 

 addition to the absence of water sprouts with Pyrus serotina stock, it 

 is much more desirable than Pyrus communis because it is now known 

 to be highly resistant to blight. This phase of the subject is fully 

 treated in chapter on fungous diseases in connection with the pear blight 

 discussion. 



