DISEASES OF THE QUINCE. 85 



The bacterial theory seems to account for all the 

 phenomena connected with this disease. The bacteria 

 found in the disease will produce it from inoculation in 

 about a week; and by the second week the stem and 

 leaves of the twig will be dead, and by the third week 

 the disease will be extended down the limb, marking its 

 progress by the brown bark and blackened leaves peculiar 

 to the blight. 



Bacteria may enter through the flowers as well as the 

 tender tissues of the growing twigs, or any opening in 

 the older bark of the trunk and limbs. No visible effect 

 is likely to be seen for several weeks. In June, and on- 

 ward for a number of months, it may be seen as branch 

 after branch reveals its presence. It grows very slowly 

 in cold weather, and rapidly in warm and moist weather. 



I have found the annual salting of both quince and 

 pear trees, when done before the spring growth begins, 

 to operate as a preventive ; but can not say there will 

 be none in the future. Later salting has not always pre- 

 vented it. When the disease is manifest, no time should 

 be lost in removing and burning the diseased portions. 

 Be sure to cut far enough below the affected parts to re- 

 move all the disease. 



So long as there remains any portion of the trunk or 

 branches not encircled with the blight, the tree may re- 

 cover. I have trees that have done good service for 

 several years, which were all destroyed except a strip on 

 one side. The diseased parts were cut away, splitting off 

 the blighted wood from one side of the trunk, and the 

 rest has grown well, now nearly covering the split portion. 



Accepting the bacterial theory of the disease, we might 

 propose to control it by spraying the trees with some 

 antiseptic ; but in practice the best thing we can do is 

 to prevent it as far as possible, and diligently destroy 

 every trace of the disease. 



The microscope shows that both leaves and fruit are 



