Connecticut western news., 1884-09-10
INVESTIGATIONS OF PEAR BLIGHT.
1t Is Not Confined to the Pear but Attacks
 Other POmRceous Fruits.


 A bulletin issued from the New York Agricultural Experiment Station was devoted to observations on pear blight by the station botanist, Prof. J. O. Arthur. Following are extracts from these observations:
 July 16 peach orchard was visited and diseased branches secured. Among these was one with viscid, yellowish drops exuding from the stem. With needle a puncture was made about an inch from the extremity of several branches of pear tree in the garden, and very little of this excretion in- serted. In from six to eight days every branch inoculated showed unmistakable signs of the blight The bark turned brown and then blackish about the puncture, the color extending gradually through the stem, passing upward to. ward the end of the branch much faster than downward or around the branch. On the ninth day most of the wounds exuded some of the same viscid fluid | were all removed on the thirteenth day to prevent the disease securing any permanent hold on the tree. Most of the infected branches were blackened for foot or more, and all the tender young leaves as well, all being thor oughly dead. It was noticeable that the ll-grown leaves were rarely affected, and mostly remained green up to the time of the removal of the branch. Only one of the inoculated leaves became infected, and this was young, tender one. The disease spread to the stem and worked the same as in the other cases. At the same time portion of the same virus was applied to two young apple branches. Both showed the dis ease in eight days. It spread gradually until on the thirteenth day about two inches from the apex was quite dead and dry, and the branches were re- moved.
 July 24 an inch or so of diseased pear stem was sliced up in watch-glass half full of water, and after stirring about the chips were all removed, which left the water slightly milky. This was used to inoculate with, by making puncture with pin and adding small drop from the watch-glass. It was ap- piled to the branches of several kinds of fruit, but sufficient time has not elapsed at this writing to show results, except in the case of 8 very young branch of Juneberry, about six inches long, which showed unmlstakable signs of blight on the sixth day. But the most remarkable results yet secured were gotten by in- oculating the fruit of Bartlett pear with this watery infusion. On the sixth day they were all blackened for some dis tance around the point of inoculation, and exuding copious flow of yellowish fluid which ran down the side and dropped on the ground. In fact, each was great running sore. Upon cutting open the pears, they were found to be discolore5 almost throughout their in- terior. Inoeulation at the same time on quincs fruits showed the decrease in seven days, but without any exudation, and upon cutting them open, only about one- fourth the interior was affected.
 Prof. Arthur makes the following gen. eral statements, which some sixty ex- periments at the time the report was written fully sustain: Pear blight is in- fectious, and may be transmitted from one tree to another by inoculation. It is not confined to the pear, but may at- tack other pomaceous fruits, ss the ap- pie, quince, English hawthorn and Juneberry. It is most active, and pro- gresses most rapidly upon young and succulent portions of the tree. Under the microscope any bit of diseased tis- sue shows inconceivable myriads of mi mute bacteria, which fill the water of the slide in which it is mounted like cloud. It is therefore not necessary to depend on external appearances in order to de- termine the progress of the disease in a branch, for the microscope will decide with absolute certainty. There cannot be rational doubt that the bacteria are | tho oonoo oR kha Iiaaaaa