THIRTY-SEVENTH ANNUAL REPORT. 11 



a very large proportion of the vines were torn out and grape growing was 

 practically abandoned. 



If during the next five years the weather in southwestern Michigan is 

 similar to that experienced during the last three years, it can be stated 

 positively that the grape crop will suffer even more than it has during 

 the last year or two, as the disease will spread and apparently increase in 

 virulence unless steps are taken by the grape growers to control it. 



There is no occasion, however, for discouragement and it may even be 

 found that the black rot of the grape will prove a blessing in disguise, to 

 the vineyardist who gives his vines proper attention in the way of spraying, 

 just as the San Jose scale has actually increased the net profits from orchards 

 'where it has appeared by forcing the owners to spray them. It would not be 

 surprising if a continuance of the black rot would have a similar effect upon 

 the net proceeds of the vineyards, if proper attention is paid to spraying. 

 Benefits sufficient to more than equal the cost of spra^dng can be expected 

 from both of the following causes: First, the spraying needed to control 

 the black rot is the very best specific against mildew, anthracnose and other 

 fungous diseases which not only seriously injure the grapes themselves, 

 but by attacking the leaves, reduce the vigor of the vines and hence lessen 

 their ability to produce fruit; second, it cannot be expected that every person 

 will spray his vineyard and as the grapes upon unsprayed vines will be de- 

 stroyed and the vines themselves will be dug out, if the loss continues for 

 a series of years, the result will be a sm.aller crop of grapes and an increase 

 in the price. 



It is now about twenty-five years since it was discovered that copper 

 sulphate was a sure specific against the black rot. This disease spreads 

 from spores which winter over in the rotten grapes and leaves, and which 

 germinate whenever they fall upon a drop of water upon a grape or grape 

 leaf. If the foliage and fruit can be kept covered at all times with a thin 

 film of copper sulphate, it will not be possible for the disease to get a foot- 

 hold, and there will be no injury whatever from it. 



From this it will be seen that it is only a question of spraying sufficiently 

 often and thorough enough to keep the grapes covered. This is not theory, 

 but is based upon the writer's experience with this disease more than twenty 

 years ago in Missouri and upon experiments that have been carried on iia 

 various parts of Michigan for the last three years. The results thus obtained 

 have,_ in every case, been substantiated by many grape growers who have 

 practiced spraying under proper conditions. I venture to assert that every 

 case of failure has been due to the lack of compliance with the condition 

 mentioned above, which, as you will remember, was that the foliage and 

 fruit be kept covered with copper sulphate continuously up to the time 

 the fruit is harvested. While there has been a large amount of rot in vine- 

 yards that were sprayed from one to four times during the season, it is very 

 certain that one of three mistakes were made. Either the material was 

 not properly prepared, it was not applied at the proper intervals, or there 

 was a lack of thoroughness in the applications. 



MATERIALS FOR SPRAYING. 



For the black rot of the grape, as for nearly all other fungous diseases 

 there is no remedy equal to Bordeaux mixture, in its cheapness, efficiency 

 and safety. For the earlier applications it will be well to use four pounds 

 of copper sulphate, six pounds of stone lime and fifty gallons of water, or 



