The Red Grape
( Originally Published Early 1900's )
H. F. MINERS, ST. JOSEPH.
(First Prize Address.)
During the last decade Michigan Horticulture has suffered a great many serious setbacks and large amonts of money have been lost through disease but to my mind Michigan grape growers have never had a more serious disease to contend with than the so-called "Red-Grape" or downy mildew. Hundreds, yes, thousands of acres of grapes have either been ruined or else partially ruined during the present year in south-western Michigan through this little understood disease.
Coming as it does in the early summer its advance is not noticed until it is too late. It makes its appearance in early summer as a ,white cottony mass on the canes and the under side of the leaves. Since this growth is not at- all conspicuous in appearance it is not noticed until the fungus attacks the berry along in August. The berry then turns a pinkish red long before it is time for it to ripen and about the time it should ripen the berry shrivels up and is easily shaken to the ground, thus either ruining the bunch or else spoiling its appearance. Since none of this white cottony mass appears on the berry, to the casual observer there is seemingly no cause for the disease.
Along in the early part of the summer, shortly after the fungus first appears little spores or seeds are formed which are blown about the vineyard and give rise to a spread of the disease. However, these little spores or seeds are not hardy and will not live over winter but along in August more spores or seeds are produced which are hardy and frost-resistant and which live over winter to reproduce the disease again the following spring.
Wet weather seems to be particularly favorable for the production of this disease and it is at its worst during a wet year. As a natural consequence it spreads worse during the very hot weather following the rainy periods.
However, the disease can be thoroughly and absolutely controlled by a systematic spraying with Bordeaux mixture. The same spray may be used which is used to control black rot and six applications should be sufficient. Better still, a spray should be applied just before each rainy period, the time of which can be fairly accurately determined by a careful study of the weather maps and bulletins. Where the six applications are used, however, spraying should begin about the time the flowers open and continue every two weeks thereafter until five or six sprayings have been applied. Great care should be exercised to see that the spraying material is applied directly to the under side of the leaves for it is here the disease is worse.
It is a known fact that Michigan grape growers are very reluctant to take up any preventive or control measures and in the, past in a good many sections have absolutely refused to spray their fruit. During the present summer I saw vineyard after vineyard where almost every grape could be shaken to the ground, I saw hundreds and thou-sands of acres of profit turned into a loss. I saw grapes loaded in cars in more than one shipping point in southwestern Michigan which were not fit for hog feed. I make this statement because I happen to be a farmer in the district which I have mentioned and I know it to be true. I know of a good many prosperous and seemingly well educated farmers who scorn the idea that they must spray their fruit and laugh when you tell them that a continuation of present methods mean the ruination of the grape industry, but unless they are willing to listen to good authorities such as are provided for by our government and state at their experiment stations and colleges and take the proper precautions to control this disease and others, the grape industry of Michigan will soon become a thing of the past, and so again I repeat gentlemen, that unless the farmers wake up to the fact that they must take drastic measures to control the red grape, the black rot and the like, just so sure are we going to witness the death of one of the greatest farming industries that southern Michigan has ever known.