THE DISEASES OF PLANTS 109 



several millions of dollars. All that is needed to prevent 

 this loss is a little care in the treatment of seeds. 



EXERCISE 



Count the smutted heads on a patch three feet square and estimate 

 the percentage of smut in all the wheat and oat fields near your 

 home. On which is it most abundant ? Do you know of any fields 

 that have been treated for smut? If so, look for smut in these fields. 

 Ask how they were treated. Do you know of any one who uses 

 bluestone for wheat smut? Can oats be treated with bluestone? 



At planting time get an ounce of formalin at your drug store or 

 from the State Experiment Station. Mix this with three gallons of 

 water. This amount will treat three bushels of seeds. Spread the 

 seeds thinly upon the barn floor and sprinkle them with the mixture, 

 being careful that all the seeds are thoroughly moistened. Cover 

 closely with blankets for a few hours and plant very soon after treat- 

 ment. Try this and estimate the per cent of smut at next harvest time. 

 Write to your Experiment Station for a bulletin upon smut treatment. 





FIG. 93 FIG. 94 



A SCABBY SEED POTATO A HEALTHY SEED POTATO 



The Potato Scab. The scab of the white, or Irish, potato 

 is one of the commonest and at the same time most easily 

 prevented of plant diseases. Yet this disease diminishes 

 the profits of the potato grower very materially. Fig. 93 

 shows a very scabby potato, while Fig. 94 represents a 

 healthy one. 



