1890.] PUBLIC DOCUMENT — No. 4. 33 



least, I lind it so, and I have two thousand trees outside the 

 hen yard. I have average crops every year. It may he that 

 I raise so many that the curculio cannot sting them all. 



Question. Do you ever spray your trees with Paris 

 green ? 



Mr. Hawkins. I have never had occasion to. 



Mr, Augur. I would like to ask which varieties of your 

 plums have been most troubled with the black-knot? Have 

 you noticed any difference in the varieties ? 



Mr. Hawkins. My worst trees in that respect are the 

 Damson and the Purple Gage. I have an orchard of Lom- 

 bard trees that have been set for ten years, and they have 

 never had knots enough on them to injure the crop to any 

 extent. The Quackenboss seems to be the freest from the 

 disease in my locality. 



Mr. Augur. Have you the Niagara? 



Mr. Hawkins. I have. I suppose they are the same as 

 the Bradshaw. That is what the growers tell me at Geneva. 



Mr. Augur. There is a little difference between them, I 

 think. 



Mr. Hawkins. They call them the Niagara in order to 

 sell them for a new thing ; but they are practically the Brad- 

 shaw, as far as I can see. I bought a few at a high price, 

 but they all bore Bradshaw plums. 



The Chairman. The hour of adjournment has come, but 

 Professor Humphrey, of the Experiment Station, is present, 

 and I know we should all be glad to hear from him on the 

 subject of the black-knot. 



Professor Humphrey. Mr. Chairman and gentlemen, I 

 am not here to talk to-day, but when I saw the eye of the 

 secretary on me I knew 1 was in for it. This question of 

 the black-knot is one on which I have not much to add to 

 what has been said in the bulletin of the Hatch Experiment 

 Station of the Agricultural College for October, which some 

 of you I presume have read. I can tell you in a very 

 few words what we know about the black-knot. It would 

 take a good many more to tell you what we do not know. 

 The swelling in the branches known as black-knot or wart 

 on cherry and plum trees is caused by the attacks of a 

 little plant. It is just as truly a plant as the plum tree that 



