212 MINNESOTA STATE HORTICULTURAL SOCIETY. 



literature in my paper. The literature begins way back in 1794 and 

 runs all the way through, even down to this one of Mr. Peffer's. 

 At the time he mentioned this feature he did not use this argument 

 all the way through, but in a general way he explained that the dis- 

 ease was caused from a similar reason as that mentioned by the 

 gentleman who spoke last. You will notice it is called "frozen sa_p 

 blight." The thought was this, that as the sap exuded it would 

 poison the tree. As I said, that was the thought really all the way 

 through. In the demonstration I gave you I mentioned some of 

 the tests that were made. He worked about six or eight years on 

 this, and in no case did he find a blight in which these bacteria did 

 not exist ; he could not find a case where this sap exuded and blight 

 appeared where these bacteria were not present. It showed it was 

 a poison, and he tried to infect a tree with this disease. The con- 

 dition of the tree, of course, would make a difference as to whether 

 it would take the disease or not, just like it would be a question 

 whether you and I would be susceptible to a certain disease if we 

 were exposed. The poison that was mentioned brings out another 

 fact. I said that in all other cases where the tree was afterwards 

 affected the disease had been caused by a puncture below the place 

 affected. We have an opening there so the disease or the germs 

 can get inside. I said nothing about varieties, because there was 

 not time, and there being tests made to see whether one tree contains 

 a greater amount of moisture than another and whether it is there- 

 fore more readily attacked. It seems to me most probable that in 

 most of the cases there is more moisture in the wood in the cases 

 of those varieties that are so readily attacked by blight. Another 

 thing was mentioned, that is, in regard to the amount of moisture. 

 In that one case you get the sap conditions in which this bacteria 

 can live and thrive and multiply so rapidly. As Mr. Waite says, 

 that is the most favorable condition for their existence. If they 

 dry up and die it proves that the circulation is very rapid and this 

 moist condition disappears. I think that covers the ground. 



Mr. D. S. Hall : I planted an orchard fifteen or twenty years ago, 

 and the greatest enemy I had on the place was blight. I have been 

 told to cultivate the orchard. I have tried that, I seeded it down 

 to timothy and clover, I mulched it for some years, and for some 

 years I did not mulch. I did everything I was advised to do by those 

 who I thought had more experience than I had, but it was of no 

 avail to check the blight, and for that reason I am especially inter- 

 ested in this subject of blight, as I think all of you are. I have taken 

 a great deal of interest in what Prof. Robertson told us, but he did 

 not tell us what I most wanted to know. He said blight was caused 

 by a bug with some unpronounceable name. They say it is a bug 

 and then let it go at that. The main thing that the people are in- 

 terested in is not to know whether it is a bug or anythmg else, nor 

 do they care what kind of a name it has, the principal thing is to 

 know what remedy to apply to prevent it, something that will help 

 us and relieve us of this condition and permit us to grow fruit on 

 our trees. I asked the question several times today if there is any 

 known way or method to combat the disease other than by cutting 



