TUBER CROP PROJECTS 213 



1. What implements will you need to cultivate your potatoes V 



Fr: 107-110. Gi: 160-169. 



2. Give complete instructions for the season's tillage operations. 



Fr : 105-110. Gi : 160-169. 



10. Combating insects and diseases. — It is impossible to pro- 

 duce a good crop of potatoes without the proper control of disease 

 and insect enemies. Apparently a large percentage of commercial 

 growers do not fully appreciate this factor in the successful pro- 

 duction of potatoes. 



If we fully realized the function of perfect, healthy foliage in 

 the growing, of large tubers, more attention would be given to pro- 

 tecting the leaves against the attack of both insects and diseases. 

 Let us remember that the leaves are the great laboratories of the 

 plant and that the tubers cannot develop without them. The 

 elements which enter the plant through the roots and leaves are 

 combined into starch in the leaves and then transported through 

 the stem and stored in the form of tubers. It is readily seen, 

 therefore, that any curtailment in leaf surface, due to the ravages 

 of insects and diseases, will certainly limit the plant in its ability 

 to produce starch and tubers. If there is only half a crop of 

 leaves we cannot expect more than half a crop of tubers, while a 

 full crop of leaves, accompanied by favorable cultural conditions, 

 should result in a full crop of tubers. The problem, then, is how to 

 save all the leaves in a perfect state of health. 



Insects and diseases affecting the foliage may be controlled by 

 spraying. The first applications should be made before the 

 enemies appear, and this means soon after the plants are up. 

 Flea beetles may be the first to arrive and Bordeaux mixture will 

 repel them. Additional applications should be made as often as 

 may be necessary to keep the leaves well protected. 



Both the upper and lower surfaces of the leaves must be 



