59 



(d) Paris green: its chemical composition; its protective 

 action against the insect enemies of the potato plant; 

 dangers attendant upon its use; its possible combina- 

 tion with Bordeaux mixture; and the best formula, 

 method of preparation and periods for its application. 

 /. Proper Cultivation. The related study here would include 

 knowledge of : 



(a) Physical characteristics of the soil, particularly the 



capillary movement of water to the surface of the 

 soil, and exhaustion of soil moisture by evaporation. 



(b) Surface conditions most favorable for receiving rain 



water without washing, puddling or subsequent 

 baking. 



(c) Value of a " soil mulch," and the most desirable method 



and frequency of cultivation for maintaining such a 

 mulch. 



(d) Comparative cost and advantages of " level " and " hill " 



cultivation, and reasons for the choice of the par- 

 ticular method to be followed in cultivating the present 

 crop. 



B. Insuring the cleanest crop by : 



a. Dipping the "seed" potatoes in a formalin solution. The re- 



lated study here would involve knowledge of : 



(a) Plant parasites which produce " scabby " potatoes, and 



the biological conditions favorable and antagonistic 

 to their growth. 



(b) Formalin solution: its chemical constitution; its chemi- 



cal action on these damaging potato parasites; and 

 the proper formula and method for its use in pro- 

 tecting the potato crop. 



b. Substitution of chemical fertilizers for barnyard manure. The 



related study here would involve knowledge of : 



(a) Dangers of infection from the use of barnyard manure. 



(b) Dangers of infection, if any, from the use of chemical 



fertilizers. 



C. Insuring the soundest crop by spraying the potato plants with 



Bordeaux mixture. The related study here would involve 

 knowledge of : 



a. Bacterial and fungous diseases to which the potato plant is 



subject; evidences of their presence; and whether or not 

 they are preventable. 



b. Bordeaux mixture: its chemical composition; its protective 



action against potato-plant diseases; and the best formula, 

 method of preparation and periods of application for its 

 use. 



