vinal] AN OUTLINE FOR STUDYING THE POTATO 193 



IV. Uses of the Potato 



A. In the Home. The potato stands next to wheat as an im- 

 portant food crop in the western countries. 



Potato Starch. The making of starch is both valuable and 

 interesting. Grate potatoes into a dish of water. The starch 

 granules settle on the bottom of the dish. Keep rinsing with 

 water until the starch is white and clean. Send for Recipes for 

 the use of the Potatoes and Home-made Potato Starch, Form O-7, 

 to the States Relations Service, U. S. Department of Agriculture. 



Boiled Potatoes. Most economical to boil in jackets. If pared, 

 place in cold water to prevent coloring. If of uniform size they 

 are done at the same time. Place in hot water instead of cold — 

 will not be soggy. Salt added to water makes the potatoes more 

 tasty. Drain off water. 



Baked Potatoes. More wholesome than boiled potatoes. Place 

 in a hot oven until soft. Break skin to let out the steam. 



B. Commercial Uses. Denatured alcohol; sizing for paper; 

 thickening colors in calico printing; glucose. 



V. The Potato-Beetle 



Aim : To know the life history and means of protection of the 

 potato-beetle in order to exterminate it. Teach when needed. 



Place the larvae of the potato-beetle on a potted potato plant 

 which may be kept in a breeding cage. 



In what way are the larvae injurious to the plant ? How might 

 we attack the insect in this stage? Handle the larvae and note 

 the odor left on the hands. Would birds enjoy eating the larvae ? 

 Why? (A distasteful secretion protects them from birds). Of 

 what advantage are the bright colors of the larvae to itself? 

 (A warning to birds). The larvae change into the pupal stage 

 beneath the ground. How would fall plowing help destroy this 

 pest ? In what way would rotation of crops help this problem ? 



Study the adult. Feed the insect on raw potato. Note whether 

 the adult has sucking or biting mouth parts. (Biting mouth 

 parts). Does the adult or the young larva have the greatest 

 appetite? Compare the size of the legs with those of the ground 

 beetle? (Smaller). What does this indicate? (Depends more 

 on wings for locomotion). In what way does this suggest the 

 need of co-operation amongst farmers of a neighborhood? (If 

 each one does not kill these pests they will soon infect clean areas). 



