DISEASES AND PESTS OF PLANTS. 69 



very satisfactory. By pouring the mixture oil the top of the cone it will strain 

 readily with little clogging, and is more satisfactory in this respect than a flat 

 strainer. 



The following tests are good ones to show whether the copper sulphate has all 

 been neutralized by the lime : 



Potassium Fcrrocyanide (in Solution). No change on adding to mixture. If 

 more lime is required, it turns a purple or reddish colour. 



Blue Litmus-paper. No change. If it turns red, more lime is required. 



Knife-blade. If metallic copper precipitates on the blade, the mixture requires 

 more lime. The potassium ferrocyanide is the best and cheapest indicator. 



Bordeaux mixture, double strength (8-8-40), is to be recommended for fall spray- 

 ing for the black-spot canker. The ordinary mixture is a valuable spray for potato- 

 blight and various other vegetable-diseases. 



Sticker 



Resin 2 Ib. 



Sal soda 1 Ib. 



AVa tor 1 gal. 



Boil this mixture until it is of a clear brown colour, which takes from one to 

 one and a half hours. Cook in an iron kettle in an open place. Add the above to 

 40 gallons of Bordeaux for use on smooth foliage, like onions, cabbage, or asparagus. 

 If used with arsenate of lead or Paris green, add 1 to 2 Ib. of fresh lime to every 

 40 gallons. 



Soluble S id i>lnn\- -This is a patented preparation containing 58 to GO per cent, 

 soluble sulphur and 40 to 42 per cent, inert matter. It is recommended by the 

 manufacturers as a spray to take the place of lime and sulphur. The compound 

 comes in dry form in various sized packages and is easily handled. For winter 

 spraying the strength recommended is 1 Ib. soluble sulphur to 4 gallons of water, 

 and for sulnmer spraying 1 Ib. to 40 gallons of water. Some growers have reported 

 good results with this spray, but, on the whole, the results of the experiments carried 

 on fur two years by the Department have been varied and conflicting. 



Atomic Sitlitlnir.-- A spray manufactured by the General Chemical Company of 

 California and recommended for the summer spraying of fruit-trees, especially those 

 with tender foliage. It is recommended for practically everything that lime and 

 sulphur is used for during the summer and is reported giving good results. It has 

 not been used to any extent in this country, but is worthy of trial for the powdery 

 mildews on apples and peaches. 



Precipitated Fu1i>lnir. After testing out all standard fungicides and many new 

 preparations this spray gave the best results in California in the control of apple- 

 mildew. In the tests made it was prepared as follows: 2 Ib. iron sulphate dissolved 

 in 10 gallons of water. To this add concentrated lime and sulphur slowly until no 

 more black precipitate is formed ; allow to settle and pour off clear liquid. Water 

 is added again and the same operation is repeated two or three times. The black 

 precipitate is then mixed with 100 gallons of water and used as a spray. Arsenate 

 of lead and nicotine sulphate can be used with this mixture without impairing its- 

 fungicidal value. Some fruit-growers in Hood River report good results from adding 

 the iron sulphate and arsenate of lead to the lime-sulphur after the latter is diluted 

 in the spray-tank. 



Combination Sprays. It frequently happens that the time to spray for some 

 biting or sucking insect coincides with that for a fungus-disease. It is therefore 

 possible by combining various sprays to make one operation do the work of two or 

 even three. The following has been successfully used against aphides, scab, and 

 leaf-eating caterpillars: Lime-sulphur (concentrated), 3 gallons; 40-per-cent. nicotine 

 sulphate, % pint; lead arsenate (paste), 5 Ib. ; water, 100 gallons. The foregoing 

 spray gives the best results in the Dry Belt when applied immediately before the 

 blossoms open. If any of the ingredients are not necessary they may be omitted. 



NOTE.- Never add soap to a spray containing lime-sulphur. 



