ELEVENTH ANNUAL MEETING. i39 



These discolored areas are caused by frost or other unfavorable 

 conditions, and are not due to the presence of a parasite. 



The disease known as black knot, common on cherry and 

 plum, is easily recognized. The knots are usually brown at 

 first, but become black as they get older. Black knot is pro- 

 duced by a fungus that attacks the twigs and branches of the 

 wild as well as the cultivated species of both the plum and the 

 cherry. These knots should be cut out as soon as they appear, 

 and the trees should be thoroughly sprayed with a copper 

 fungicide. 



In connection with all fungus diseases, too much emphasis 

 cannot be put upon the importance of thorough work in spray- 

 ing. Some growers have sprayed with very satisfactory results, 

 while others have been less successful. A failure to get good 

 results in spraying is often due to an improper preparation of 

 the fungicide or to a lack of thoroughness in its application. 

 It is true that the kind and condition of the tree, the stage of 

 development of the fungus, and the state of the weather, are all 

 important factors which contribute much to the success or 

 failure in the use of fungicides. 



The black rot of the grape is probably the most serious pest 

 with which the grower of this fruit has to contend. Under 

 ordinary conditions the disease may be controlled by the use 

 of Bordeaux mixture. Usually five or six applications during 

 the season are necessary. It was in connection with the black 

 rot of the grape that Bordeaux mixture was discovered in 

 France, near the town of Bordeaux. No fence being between 

 the vineyards and the roadway, travelers in passing along were 

 in the habit of running into the vineyards and gathering a few 

 bunches of grapes to eat as they went on their way. The large 

 number of travelers in that section carried away a considerable 

 quantity of fruit during the season and the growers determined 

 to make the grapes appear to have been poisoned. Accordingly 

 they mixed together some bluestone and lime, and threw it into 

 the vines near the roadway. That year there was a serious out- 

 break of black rot in those vineyards, but it was noticed that 

 those grapes which had received bluestone and lime mixture 

 were nearly free from black rot, while farther back from the 

 roadway, where this substance was not applied, there was con- 

 sidera1:)le disease, and from that small beginning Bordeaux mix- 

 ture has come into general use as a fungicide. 



