Minnesota Plant Diseases. 221 



Dissolve the potassium sulphide in a few quarts of hot water 

 and add enough cold water to complete the solution. This has 

 been recommended for checking powdery mildews and rust of 

 chrysanthemums and in general for greenhouse use. 

 Potassium permanganate. 



Potassium permanganate i part. 



Soap 2 parts. 



Water 100 parts. 



Recommended in France for black rot and mildew of grape, 

 etc. [Mass. Bull. No. 80 1902.] On account of expense can 

 be profitably used only on greenhouse or garden plants. It 

 has been recommended for rust diseases of hollyhocks and car- 

 nations. 



Iron sulphate and sulphuric acid. 



Water (hot) 100 parts. 



Iron sulphate As much as will dis- 

 solve. 



Sulphuric acid i pint. 



Prepare the solution just before using. Add the acid to the 

 crystals and then pour on the water. Valuable for treatment 

 of dormant grapevines affected with anthracnose, applications 

 being made with sponge or brush. [Mass. Bull. No. 80 1902.] 

 This solution should be made in wooden vessels. It has been 

 recommended for disinfection of bark, ground, etc., where dis- 

 ease has previously existed. The solution will destroy the foliage 

 so it must be used in late fall or early spring, or applied only 

 to tree trunks. 



STEEPS. 



Formalin. (A) For oat smut and stinking smut of wheat. 



Add one-half pound of formalin to thirty gallons of water 

 and immerse the seed grain for two hours, then spread out and 

 dry. 



Or, sprinkle the grain with the formalin solution until thor- 

 oughly wet, shoveling over rapidly to distribute the moisture 

 evenly, then place in a pile (covered with sacking) for two hours 

 and finally spread out and dry as in the first method. 



