'pi'e (anadian f|ortic(ilr(irist 



NOVEMBER, 1904 



Volume XXVII 



Number 11 



THE BLACK ROT OF GRAPES IN OHIO 



PROF. W. LOCH HEAD, ONT. AGRI. COLLEGE, GUELPH. 



AT the request of the Minister of Agri- 

 culture, I recently visited the grape 

 districts of northern Ohio to ascertain the 

 best methods of dealing with the black rot 

 of grapes. In Ontario, in the Essex dis- 

 trict, black rot has been more or less preva- 

 lent for some years, but no sustained effort 

 was made to check the progress of the dis- 

 ease. The result was that fruit growers 

 of that district found it necessary to pull 

 out the vines and plant to other uses. Many 

 of the old vineyards which were objects of 

 ])ride five or six years ago along the Detroit 

 river have now disappeared. In the Nia- 

 gara region, where the grape industry is de- 

 veloping on a commercial basis, the black 

 rot is beginning to be felt, and grape grow- 

 ers fear they will suffer the same fate as the 

 Essex growers if they do not try to combat 

 the attacks of the fungus. 



Through the kindness of Prof. Selby, of 

 the Ohio Agricultural Experiment Station 

 at Wooster, I was directed through the vine- 

 yards along Lake Erie from Unionville on 

 the east to Sandusky on the west. Besides, 

 he gave me letters of reference to many of 

 the prominent owners of vineyards in the 

 Cleveland district, with whom I consulted 

 regarding their methods of treatment. The 

 results of the experiments these growers 

 have conducted have been very gratifying. 

 They were conducted on the cooperative 



plan, that is, the owners and the Experiment 

 Station worked together to control the 

 disease. 



Six sprayings* are recommended by Prof. 

 Selby for the Delawares, seven for Cataw- 

 bas, and eight for the Concords. He states 

 that the Catawbas and Niagaras are the 

 most susceptible to rot ; the Delawares quite 

 resistant; and the Concords not so suscepti- 

 ble as the Niagaras, but less resistant than 

 the Delawares. He does not believe that 

 early sprayings are of much use, and he 

 bases his belief on the results of spra>'ings 

 carried on for three years. 



WHEN SPRAYINGS SHOULD BE DONE. 



The first spraying is given when the 4iew 

 shoots are from one to two feet in length, 

 which in the Ohio district is about June i ; 

 the second spraying is applied about July i 

 in an ordinary season. These two spray- 

 ings are considered the two most important, 

 inasmuch as they come immediately before 

 and after blossoming. Many of the grape 

 growers told me that if they failed to spray 

 on or about July 4 they almost invariably 

 lost their grapes. The subsequent spray- 

 ings are given at intervals of a week or ten 

 days, and the last for the Delawares is usual- 

 ly applied about August i. The first four 

 applications are made with Bordeaux mix- 

 ture, and the remainder with either am- 

 monia-carbonate solution or soda-bordeaux. 



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