144 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



on the thorax, but otherwise the body appears perfectly smooth 

 to the eye, though finely wrinkled. Before pupation the color 

 becomes slightly darker and the body shortens. Leaving the 

 roots, the larvse then form small oval cells in the soil and in them 

 transform to pupse, from which the adult beetles emerge in a 

 short time. The beetles appear from the middle of July on 

 through August, about two months being required for development 

 after hatching from the egg. The beetles are of a greenish or 

 greenish-yellow color, about one-quarter inch long, and resemble 

 the common striped cucumber-beetle (page 340) in form. They 

 are to be found in the corn-fields feeding upon pollen and silk 

 until the latter becomes dry, and lay their eggs during August 

 and September. The beetles are often found feeding upon various 

 weeds, clover, beans, cucumber and squash vines, and the blossoms 

 ot thistle, sunflower and golden rod. 



Control As the larvae feed only on corn, if the corn-field be 

 planted to some other crop, starvation results, and a simple rota- 

 tion in which corn is not allowed on the same land for over two 

 years in succession usually prevents injury, though a field in which 

 injury has occurred should be planted to some other crop at once. 

 It is imprudent to plant corn on fields in which the beetle has been 

 observed feeding in large numbers on clover and weeds during the 

 late fall of the previous year. The liberal use of manure and fer- 

 tilizers, and thorough cultivation will, of course, be of service in 

 enabling the plants to withstand attack. 



ii 



The Southern Corn Root-worm * 



Closely related to the last species, but with somewhat different 

 habits, the Southern Corn Root -worm is frequently injurious to 

 corn from Maryland and southern Ohio southward. 



The adult beetle is of a bright green marked with twelve black 

 spots, which have given it the name of 12-spotted Cucumber- 

 beetle to distinguish it from the Striped Cucumber-beetle (page 340), 

 with which it is often associated feeding on cucurbs. It is some- 

 what larger and more robust than D. longicornis, and is almost 

 omnivorous in its food habits, feeding upon the foliage and flowers 

 of a long list of forage and garden crops, to which it often does 

 considerable damage. Beans are frequently injured in much the 

 * Diabrotica 12-punctata Oliv. Family Chrysomelidoe. 





