VEGETABLE INSECTS. 



275 



in the soil around the roots of a great variety of plants. Although 

 provided with three pairs of legs, they are not able to walk. The 

 head is light brown in color, and has well developed raouthparts. 



These white grubs have a life cycle of about one year in duration. 

 The eggs are laid in the soil and hatch in about two weeks. The 

 grub stage then lasts for a period varying from six to twelve months. 

 U is during this larval or grub stage that the damage is done to the 

 vegetable crops, the grubs trimming off the tender young roots and 



girdling the larger 

 ones so that the af- 

 fected plant soon 

 dies. AVhen full 

 grown the grub 

 changes to the pupal 

 or resting stage 

 which lasts for about 

 a month. Then it 

 changes to the adult 

 beetle which emerges 

 from the soil to mate 

 and feed. 



C.onirol. — It is 

 very difficult to con- 

 ti'ol these pests, and 

 no very satisfactory 

 or })ractical methods 

 have as yet been dis- 

 covered for entirely 

 getting rid of them. 



In general, crop 

 rotation should be 

 practiced, the grubs 

 should be collected by hand when the land is plowed, and when pos- 

 sible, land known to be infested with the grubs should not be planted 

 to vegetable crops. 



BEANS. 



BEAJsr LEAF-BEETLE (Cerotoma ruficornis). 



Of considerable importance to bean growers is the bean leaf- 

 beetle (Fig. 32). It is a small, reddish-brown beetle with black 



Fig. 30. — May-Beetle {Phyllophaga s^.). Adult. 



