INJURING THE LEAVES. 169 



Remedies. — According to Professor Gillette, " the 

 -only remedy at present known is to pull the vines 

 as soon as they are found wilting and burn them. 

 If the tops are left until it is time to dig the potatoes 

 many of the beetles will have matured and escaped, 

 and these will live over winter and lav eggs for an- 

 other brood." But even late pulling and burning 

 will destroy many of the pests, and in regions where 

 this insect is known to be at work, the vines should 

 be burned when pulled up in harvesting the crop. 



INJURING THE LEAVES. 



The Colorado Potato-beetle. 



Doryphora decemlineata. 



This insect originally lived upon a wild variety of 

 Solanum (the genus to which the cultivated potato 

 belongs) in the West, near the base of the Rocky 

 Mountains. It was not known as an injurious spe- 

 cies until about 1860, when it attacked potatoes in 

 the gardens of settlers in Kansas and neighboring 

 states, and thereafter gradually spread eastward 

 until it finally reached the Atlantic coast, and was 

 carried across to Europe, becoming extremely destruc- 

 tive wherever it appeared. 



The adult Colorado Potato-beetle (Fig. 87, d) is 

 too familiar to American gardeners to need descrip- 

 tion here. Its orange-colored eggs (a) are deposited 

 in masses, varying in number from a .dozen to fifty 



