200 THE POTATO 



rotation of crops, and treatment of infected seed 

 the same as for scab. 



Following is a description of some of the insect 

 enemies : 



THE COLORADO POTATO BEETLE 



The following is by S. Arthur Johnson, in "Bul- 

 letin 175" of the Colorado Agricultural Experi- 

 ment Station: 



"This insect (Leptinotarsa decemlineata) is a 

 native of a strip of country which lies just east of 

 the Rocky Mountain range and includes eastern 

 Colorado. In its native state the beetle lives upon 

 the wild weeds of the potato family. The chief of 

 these is the buffalo bur, but the beetle is quite a 

 general feeder on plants of this group, including not 

 only potatoes, but tomatoes, eggplant, tobacco, and 

 pepper. 



"The adult beetle is oval in shape, about three 

 eighths of an inch in length and a trifle narrower 

 than long. The ground color is yellow and the 

 wings are marked by ten black lines running 

 lengthwise. There are also black markings on the 

 thorax. The eggs are bright yellow when fresh 

 and are generally laid on the under surface of the 

 leaves in patches containing from ten to fifty each. 

 The young are dark red or brown grubs with black 

 heads. The color becomes lighter as the grubs 

 mature. 



"The adult beetles live over winter usually in 

 the ground at a depth of from four to six inches. 

 Where the ground is loose they frequently go much 

 deeper. When the ground becomes warmed by the 

 spring sun the beetles emerge and seek food plants 



