IGO ELEMENTS OF FARM PRACTICE 



3. Describe the formalin treatment of seed grain, and name the 

 diseases that may be prevented by it. 

 Arithmetic: 



1. If the yield of grain is reduced 10% by smut, how much does 

 a. farmer lose who grows 100 acres of wheat with a normal yield of 15 

 bus. per acre? How many dollars does he lose, if wheat is worth 90c. 

 per bushel? 



2. If a farmer pays 50c. for a pint of formaldehyde and uses it 

 and four hours of time to treat 60 bus. of wheat for smut, how 

 much does it cost him per bushel, if his time is worth 15c. per hour? 



3. How many acres can one seed at the rate of 13^ bus. per 

 acre, with 60 bus. of wheat? 



DISEASES OF POTATO AND COTTON 



Potato diseases are very numerous and cause more loss 

 to the crop than is caused to most other crops by disease. 

 Although the potato crop is very common, and the diseases 

 are very general, comparatively little is widely known or 

 done to prevent the losses. 



Potato scab is very common. It attacks the tubers and 

 leaves them with rough unsightly blotches. This scab 

 greatly reduces the value of the crop, though it does not, as 

 a rule, materially reduce the yield. The spores of the 

 disease live over both on the tubers and in the soil. The 

 spores on the tubers are destroyed by soaking the tubers 

 for one and a half hours in a solution of formalin made by 

 mixing one pint of 40 per cent formaldehyde in 35 gal- 

 lons of water. The seed tubers should be treated before 

 they are cut, then planted on clean land, that is, land that 

 has not produced potatoes for four or five years. Four 

 ounces of corrosive sublimate dissolved in hot water, then 

 mixed with thirty gallons of water, is also effective in de- 

 stroying scab. The tubers are soaked in it 1}/^ hours. 

 Corrosive sublimate is very poisonous and must be handled 

 with care. 



Rhizoctonia is another serious potato disease, which in 

 many sections seriously affects the crop. It affects the 

 vines, the stems and the tubers. It is controlled by treat- 

 ing the seed with corrosive sublimate, as indicated above 

 for scab, and by planting clean seed on clean land. 



Potato wilt, or brown rot, is one of the very injurious 

 potato diseases, though it has never been recognized as a 

 disease by a great many potato growers. It affects both 



