104 MASSACHUSETTS HORTICULTURAL SOCIETY. 



To combat such enemies to our fruit crops is what we are here for. 

 Ellwanger & Barry, the great Rochester nurserymen, some years 

 ago had a crop of four or five hundred bushels of phims ; their trees 

 were from fifteen to eighteen feet high, and they kept tliree men 

 fighting the curcuUo for from four to six weeks. Professor Lin- 

 coin had tomatoes under plum trees which were exempt from the 

 curculio, and he recommended planting tomatoes as a preventive, 

 but his trees stood where they overhung water, and it turned out 

 that this, and not the tomato plants, was the cause of exemption. 



Mr. Bates said tbft it is sixty years since he met the curculio, and 

 last year he did not find a mark. He believes that the use of the 

 knife will subdue the black wart. He once had a tree which burst 

 with black wart. He bought some trees including Green Gage, 

 and one of these developed black wart. He cut off the affected 

 part, and has had none since. 



Rev. Calvin Terrj^ had no doubt that the black wart is caused 

 by an insect. Besides the plum he had seen another shrub that 

 grows along the highways infested with it. 



Mr. Hj'de said that the black knot is not produced by an insect, 

 though insects come out of them. They are found on the choke- 

 cherry and other wild species of Prunus. 



William D. Philbrick said that the black knot had been a subject 

 of scientific investigation by Dr. Farlow, who decided that it was 

 caused by a fungus. 



Mr. Bates thought that the curculio might be frightened from 

 the plum trees. In apple and plum trees hanging over the high- 

 way, both plums and apples were free from them. 



Mr. Hyde said that a battery of artiller^^ could not frighten them ; 

 they are here to propagate their species and they will do it if they 

 can. 



Mr. Bates wanted to know if they were intelligent enough to 

 avoid trees overhanging water. He thought the exemption of such 

 trees might be explained by the water being uncongenial to them ; 

 either by its motion alone, or the sound produced by the motion, 

 or by the flashes of reflected light which came from it, they were 

 frightened avray. They are remarkably- timid insects. 



Mr. Chase said that the fruit on one side of trees planted near 

 water had been punctured by the curculio, while that on the other 

 side was not ; they are intelligent enough for that. The manner 

 in which it "plays 'possum" when disturbed is evidence of its 



