THE GKA-rE. 



5.1 



the soil is wet and cold, that the vines are very liable to become 

 diseased. On this account where a vineyard is sii Dject to these 

 troubles the first thing to do is to remedy, so far as is practicable, 

 anything that obstructs free circulation of air through it. If the 

 land is moist and cold it should be undcrdrained. For brown and 

 black rot of the fruit early bagging of the clusters will be found 

 quite effective. But after these things are done disease may gain 

 a foothold and cause serious injury to weak varieties in warm, wet 

 seasons. Some varieties are almost uniformly healthy in good 

 locations, while others are very susceptible to disease. Yet these 

 latter are often the most profitable kinds to grow for marketing 

 purposes. To grow these successfully recourse must be had to 

 treatment with fungicides, and the following is probably the best 

 method of procedure, and if carefully followed the expense of the 

 operation and the loss from disease will be very slight. 



Use of Fungicides.— As soon as the fruit has set spray the 

 vines thoroughly with Bordeaux mixture, made as recommend :.d 

 in chapter on strawberries. Repeat the spraying once in two 

 weeks until the grapes begin to color, using Bordeaux mixture un- 

 til August 1st, and after that date the ammoniacal solution of car- 

 bonate of copper, made as recommended below. Bordeaux mix- 

 ture should never be used after August 1st, or it may adhere to the 

 grapes when they are ripe and make them unsalable. The carbon- 

 ate of copper mixture has sometimes been successfully used alone 

 without the Bordeaux mixture, but the latter is most desirable be- 

 cause it stays on the vine even in very rainy weather, when the 

 former would be washed off. 



For applying these mixtures a knapsack sprayer and a nozzle 

 that makes a fine spray should be used. There are now many good 

 patterns of these offered by different companies at reasonable 

 prices. Of course a common syringe with a rose nozzle could be 

 used for this purpose, but it will be found to waste a great deal cf 

 the material on the ground and put more on the plant than there is 

 any need of. Carefully conducted experiments show that when 

 these insecticides are applied as directed there need be no fear 

 that injury will result from the small amount of copper that is put 

 on the fruit. Almost without exception the copper is all washed 

 off the fruit before it is ripe. In extreme cases where Bordeaux 

 mixture remains on the fruit it can all be taken off without even 

 injuring the bloom by dipping the fruit into water sliarhtly acidu- 

 lated with vinegar. The fruit does not absorb any of the copper. 



Ammoniacal Carbonate of Copper is made by dissolving- 

 one and one-half ounces of precipitated carbonate of copper in one 

 quart of commercial ammonia. Then add this solution to twenty- 

 five gallons of water. The ammonia should be kept tightly corked 

 in a glass or earthen vessel. The solution should be added to the 

 water immediately before spraying, otherwise some of the am- 

 monia may be lost by evaporation. 



