INJURIOUS INSECTS 



125 



be more susceptible at one time than another to applica- 

 tions of this nature. 



COMMON GARDEN INSECTS AND METHODS OF DESTROY- 

 ING THEM 



The Colorado Potato Beetle (Doryphora decemlineata) . 

 The Coloradp potato beetle is so common and so well 

 known by every farmer and 

 gardener in this country that 

 it needs no description here. 

 It came originally from the 

 Rocky Mountain region, 

 where it fed on the native 

 sandbur (Solanum rostratum), 

 which is closely allied to the 

 potato; but when this insect 

 came to know the cultivated 

 potato it preferred it to its 

 original food and has since 

 become a very dangerous pest 

 to this vegetable. The orange- 

 colored eggs, varying in num- 

 ber from a dozen to fifty, are 

 generally laid on the under side 

 of the potato leaf. They 

 hatch in about a week into 

 sluggish larvae, which feed 

 upon the leaves, never leaving 

 a plant until all the leaves are gone. They feed to some 

 extent upon tomatoes and eggplants. When fully developed 

 the larvae descend to the ground, where they pupate, 

 emerging as perfect beetles. There are three broods each 

 season. The beetles winter over in potato fields. 



Fig. 43. The Colorado potato beetle 

 in all stages. 



