U. S. EXPERIMENT STATION BULLETINS. 415 



Ions. Prepared in this way the solution will cost about two thirds of a 

 cent per gallon. 



4. — Modified Eau Celeste. 



Dissolve 4 pounds of copper sulphate in 10 or 12 gallons of water and 

 stir in 5 pounds of washing or sal soda; then add 3 pints of strong aqua 

 ammonia, dilute to 45 gallons. The cost will be 1^ cents per gallon. 



HOW AND WHEN TO SPRAY. 



It should always be borne in mind that no hard and fast rules can be laid 

 down for work of this kind. Frequently the fruitgrower will have to use 

 his own judgment, especially as regards the number of sprayings and the 

 proper time to discontinue them. If this be not done serious results may 

 follow. In the treatment of black-rot of the grape we have known vine- 

 growers to continue the application of Bordeaux mixture through a pro- 

 tracted drought up to the time of ripening of the fruit. As a result when 

 the time arrived to send the grapes to market they were so badly spotted with 

 the mixture that no one would buy them. Again we have found fruit- 

 growers thoroughly imbued with the idea that the only proper way to spray 

 was to rush through an orchard or vineyard with some new-fangled com- 

 plicated machine, applying the solutions in daubs at one point and omitting 

 whole trees or blocks of vines at another. Such work is to be regretted, 

 as it may be the cause of much loss to those who have acted carefully and 

 intelligently in the matter. For example, in the case of the grape scare in 

 New York city the past summer, grape-growers all over the country were 

 made to suffer, partly through the folly of a few over-zealous individuals 

 who upon their own responsibility made more applications than were 

 necessary and partly through the action of a somewhat hasty board of 

 health. 



Before taking up the subject of treatments proper it may be well to 

 emphasize the importance and necessity of using the right kind of 

 machinery. A sprayer to be effective requires first of all a good strong 

 force pump. Next in importance is a nozzle that will throw a mist-like 

 spray and will not clog when thick fluids are used. There are plenty 

 of machines on the market filling all these requirements. For conven- 

 ience they may be divided into three classes: (1) horsepower automatic 

 machines, (2) machines drawn by horse power but operated by hand, and 

 (3) hand machines. All belonging to the first group may be dismissed 

 with the statement that they are unnecessarily expensive and complicated, 

 and will not, even in the most careful hands do the work as thoroughly and 

 effectively as the machines belonging to the second and third groups. Of 

 the second group, in which the cheapest, most practical and efficient 

 example is found in a strong light, double-acting, double-discharge force 

 pump mounted on a barrel, it may be said that while they can not do the 

 work as rapidly as the machines of the first class, they are more effective, 

 much cheaper, and far less wasteful of the liquid used. To the third class 

 belong the knapsack sprayers, which are the only ones necessary to notice 

 in this connection. There is no question that for all moderately low- 

 growing crops the knapsack sprayer fills every requirement. In no other 

 machine is the work so absolutely at all times under control, it being pos- 

 sible to place nearly every drop of the liquid exactly where it is wanted. 



