152 Commercial Gardening 



In case the mixture is not quite properly made, owing to differences 

 in strength of the materials, it may be tested with a piece of blue litmus 

 paper, which can be obtained from almost any chemist cheaply. If the 

 blue litmus paper turns red, more washing soda should be dissolved and 

 added in small quantities, with continual stirring, until the litmus paper 

 retains its blue colour. 



RECIPE II. Sulphate of Copper and Lime. 



2 lb. sulphate of copper, 98 per cent purity. 

 1 lb. unslaked lime of the best quality. 

 10 gal. of clean water. 



This may be made up in a 40-gal. paraffin barrel also, using four times 

 the quantity of material. Proceed as follows: "Dissolve the sulphate of 

 copper exactly as has been described in Recipe 1, viz. dissolve 8 lb. sulphate 

 of copper in 35 gal. of water in the paraffin barrel. Next prepare the 

 milk of lime. For this purpose procure a wooden tub holding 5 gal., 

 and also a bucket. Put into the bucket 4 lb. of good freshly burnt 

 unslaked lime. Sprinkle it with sufficient water to change it to a 

 powder. Then add sufficient water to fill the bucket. This, when it 

 has been well stirred up, will make a thin milky fluid. Pour this into 

 the tub, and add thereto sufficient water to cool the mixture and to 

 bring the quantity up to 5 gal. After being thoroughly stirred it may 

 be slowly poured through a fine sieve such as is usually sold with 

 spraying machines into the barrel containing the copper sulphate solu- 

 tion. The contents of the barrel should be continuously stirred while 

 the milk of lime is being added to it. 



" The mixture should then be of a bluish colour and ready for use, 

 but in order to secure the best results the blue-litmus-paper test should 

 also be applied to it. If the paper turns red, a further quantity of milk 

 of lime should be prepared, and added in small quantities at a time to 

 the mixture until fresh paper put into the solution remains blue. It 

 should then be applied with as little delay as possible, and the mixture 

 should be well stirred each time before the sprayer is filled." 



It is better to dissolve the sulphate of copper and washing soda in 

 hot water instead of cold. If kept separate they will last for several days, 

 but once mixed they should be applied immediately. If the mixture is 

 kept even for a day it rapidly deteriorates, and is then much more readily 

 washed off the plants by rain. All vessels coming in contact with sulphate 

 of copper (which is poisonous) should be of ivood, and not of metal. Spray- 

 ing with a high-pressure sprayer is recommended three times during the 

 season, the first time being early and before the appearance of any blight. 

 Dry weather is obviously best for the purpose. 



Potato-leaf Curl is a disease caused by Macrosporium Solani, which 

 causes the stems to become more or less stunted, the leaves small, and 

 the leaflets much curled, and in many cases the shoots do not appear 

 above ground, thus causing gaps in the rows. The fungus appears to 



