GARDEN INSECTS 277 



them. As a rule, tomatoes are not so much injured later in 

 the season. 



The eggs hatch in from four to seven days and the young 

 grubs gorge themselves on the tender foliage, increasing in 

 size with astonishing rapidity and becoming full grown in 

 about three weeks. The grubs then enter the soil and a few 

 inches below the surface hollow out cells in which they trans- 

 form to pupae, from which the adult beetles emerge in one or 

 two weeks. Thus, in summer, the whole life cycle requires 

 from four to six weeks. After feeding a few days the new 

 beetles deposit eggs which give rise to a second generation 

 of grubs. These transform, in the same manner as de- 

 scribed, into the beetles which hibernate. Through the 

 Middle States, where most injury is done, there are two gen- 

 erations a year, but in the South there may be three genera- 

 tions and in the North there is but one. 



When the young plants are attacked by the old beetles, 

 they should be sprayed with arsenate of lead 5 pounds to 50 

 gallons. Potatoes should always be sprayed about every 

 two weeks with Bordeaux mixture for the control of diseases 

 and if this is done, the potato beetle may be easily controlled 

 by adding a half pound of Paris green or three pounds of 

 arsenate of lead to each barrel, for the first two or three 

 sprayings. Paris green is often dusted on the vines, usually 

 mixed with 50 times its weight of flour, land plaster or air- 

 slaked lime, and applied while the plants are wet with dew. 

 However, dusting is more expensive and less efficient than 

 spraying, except where peculiar local conditions make spray- 

 ing impracticable, and burning of foliage often results, par- 

 ticularly when the dust is carelessly applied. 



Cleaning up the vines and plowing potato land in the 

 fall as soon as the crop is dug will aid in reducing the num- 

 bers of the hibernating beetles. 



