PEARS— PEAR DISEASES 



1-315 



Production of Pears in United States 

 Trees, Production and Yalne 



DIVISION OR STATE 



United States 



OeograpHc Divisions: 



New England 



Middle Atlantic . , . 

 East North Central. 

 West North Central 

 South Atlantic . . . . 

 East South Central 

 West South Central, 



Mountain 



Pacific 



1910 



Trees of 

 bearing age 



15,171,624 



296,874 

 3,670,094 

 3,560,083 

 1,154,426 

 2,325,714 



831,618 

 1,045,143 



312,449 

 1,975,123 



Trees not of 

 bearing age 



8,803,886 



97,650 



1,441,505 

 589,140 

 880,461 

 506,959 

 936,230 

 417,182 



1,811,516 



1909 



Produption 

 (bushels) 



8,840,733 



233,845 



2,185,204 



1,623,176 



213,678 



975,162 



536,422 



191,518 



268,205 



2,613,523 



Value 



$7,910,600 



258,816 



2,029,040 



1,331,712 



239,838 



680,275 



450,042 



192,736 



371,306 



2,356,835 



1899 



Production 

 (bushels) 



6,625,417 



183,728 



2,186,165 



782,265 



86,804 



745.294 



180,128 



225,265 



133,482 



2,103,286 



Peaks, Grade Rules. See under AppZe 

 'Packing, 



Pears, Pollination- of. See under 

 AppZe. 



Pears, Self-Fertile and Sele-Sterile 

 Varieties. See ToTiination, under Apple, 



xEAjB diseases 



Anthracnose. See Apple Diseases, 



Black Leaf 



In this disease one side or one limb 

 of the pear tree dies and the leaves turn 

 black and hang on for some time. The 

 effect is quite similar in a general way 

 to that of pear blight, but there is no 

 sign of the presence of the pear-blight- 

 causing organism as indicated by the red, 

 juicy inner bark of limbs and twigs af- 

 fected with the real blight. Sometimes 

 there is connected with black leaf a dy- 

 ing of the bark extending in a narrow 

 strip of uniform width down the trunk 

 to the ground. All phases of this disease 

 are distinguished from the true blight 

 by the fact mentioned that there is not 

 present the red, juicy condition of the 

 inner bark, but the bark simply dies 

 down and becomes very hard and dry 

 from the first. This trouble also often 

 occurs in orchards where the blight is 

 not present and does not show the char- 

 acteristic spreading of blight from tree to 

 tree through the blossoms or by infec- 

 tion of young shoots and suckers. 



The disease appears to be more of the 

 nature of sour sap, connected most com- 

 monly with an excessive amount of 



moisture in the ground during the win- 

 ter and spring. Where individual limbs 

 are affected or narrow strips of bark on 

 the side of the trunk, it appears that cer- 

 tain roots have been badly injured and 

 that the portions affected above ground 

 correspond with such roots. 



R. E. Smith, 



California Experiment Station Bnlletin 218. 



Black Rot. See Apple Diseases. 



Blight 



The Bacterial Blight of Apples, Pears, 

 Quinces and Other Pome Fruits 



Bacillus amylovorus (Burrill) De Toni 

 P. J. O'Gara 

 Pathologist 

 In the preparation of this article on 

 pear blight the writer has in mind the 

 many requests that have been made for 

 a complete discussion of this subject. 

 Although a large number of pathologists 

 have studied pear blight from the labora- 

 tory standpoint, very few have ever car- 

 ried out successful experiments in its 

 control. To the United States Depart- 

 ment of Agriculture belongs the credit 

 of working out the methods of control 

 and putting them into practice. The field 

 work has been carried out in the East 

 and South, and on the Pacific coast in 

 California and Oregon, where excellent 

 results have been obtained. 



Early History and Native Origin 



In going over the literature on pear 

 blight we find a long array of articles 

 which describe the disease fairly well. 



