Minnesota Plant Diseases. 227 



solution should not be made in metallic vessels. [Mass. Bull. 



No. 80 — 1902.] This steep is very effectively used against 

 potato scab. 



POWDERS. 



Sulphur. "In the dry powdered state this is known as flow- 

 ers of sulphur. It may be sprinkled over plants in the dry 

 state or it may be converted into fumes by heating. Care 

 should be taken not to heat it to the burning point as it would 

 thereby form a compound that would destroy green plants as 

 well as fungi. It is usually sufficient to place it upon the hot 

 pipes of the greenhouse." This has been recommended for 

 powdery mildews and similar superficial parasites. 



Sulphur and lime. Mix the flowers of sulphur with equal 

 parts of powdered lime. This may be used in the same manner 

 as the pure sulphur. 



Dry bordeaux. "The new bordeaux powder can be made 

 by any fruit grower or gardener with very little trouble, and at 

 a very nominal expense. It can be made during the winter and 

 stored in a dry place, where it will keep indefinitely. 



'Tn order to make this new bordeaux powder one should 

 first make a large quantity of air-slacked lime. This can be 

 readily done by taking about seventy-five pounds of good 

 quicldime, pounding up the lumps and spreading it over a large 

 area, thus allowing it to air-slack readily. When completely 

 air-slacked, this should then be sifted through a fine sieve ; a 

 lOO-mesh sieve is the proper one to use. One can break up the 

 lumps in this sieve so as to utilize the "bulk of the air-slacked 

 lime by rubbing it through the sieve by means of a block of 

 v/ood. As this is a stock dust, to be used as a carrier in the 

 place of water, it would be just as well to make up a much 

 larger quantity, so as to have it on hand at a minute's notice. 

 After it is thoroughly air-slacked and sifted, the powder should 

 be kept in a dry place, such as the hay loft or the garret of the 

 house. 



"Dissolve four pounds of copper sulphate in two and one- 

 half gallons of water by placing the copper sulphate in a coarse 



