32 FUNGOID DISEASES 



and equally effective, formaldehyde solution. It 

 should be prepared in the following proportions : — 

 Corrosive sublimate . . i oz. 

 Water ... . . 7 gallons 



For scab and other superficial diseases of the 

 potato, soak the tubers in this solution for ij 

 hours at least 4 weeks prior to planting. This 

 solution must be used for Rhizoctonia disease of 

 potatoes as formaldehyde solution is ineffective. 

 Corrosive sublimate is a deadly poison, and hence 

 care must be exercised in handling it. 



8. FonnaldeJiyde SohUions. — As a preventive of 

 scab in potatoes, bunt and some smuts in grain, 

 solutions of formaldehyde have proved most effec- 

 tual. They should be prepared in the proportions 

 stated below. 



(a) For Potato Scab. 



Formaldehyde . i pint (40 per cent solution) 



Water . . . . . y^i gallons 



Place the potatoes in a coarse sack, immerse in 



the liquid for about two hours, and then spread out 



to dry. If very dirty the seed potatoes should be 



washed prior to treatment. 



(J)) For Smut of Oats and covered Sviiit of Barley . 

 Formaldehyde . i. pint (40 per cent solution) 

 Water ..... 30-40 gallons 

 Thoroughly sprinkle the grain with the solution, 

 using a watering can for the purpose while the 

 grain is being turned over on the floor, leave it in a 



