214 



PRODUCTIVE FARMING 



are sprays of poison on the growing crop. Paris green or 

 arsenate of lead is mixed with water or with Bordeaux 

 (bor-do') mixture and sprayed on the vines two or three 

 times at intervals of a few weeks. The Bordeaux mixture 

 (see Appendix) is used with the poison on potatoes for several 

 reasons. It prevents the injury to leaves by the strong 

 poisons. It holds the poison on the plants longer. It helps 

 to prevent the early and the late blight diseases of potatoes. 



Fig. 131. — Colorado potato beetle: a, egg; 



(From Smith's "Insect Friends and Enemies/') 



The Codling=moth or Apple Worm. — The worst insect 

 enemy to apple growing is the codling-moth, the larva of 

 which is the apple worm. The markets of the cities do not 

 want wormy apples. The insect which thus destroys the 

 apple crop is shown in Fig. 132. The larva spins a nest or 

 case in the crevices about the trunk of the tree where it lives 

 over winter. The adult emerges in warm spring weather, 

 and lays eggs in the blossom end of the little apple just after 

 the petals fall from the tree (see Fig. 150 C). The larva eats 

 its way into the fruit and feeds about the center. When 



