240 INSECTS AFFECTING TRUCK CROPS 



in the spring and lay eggs on the roots of common weeds of the 

 nightshade family. The larvae of this brood live in the roots of 

 these plants and later transform to beetles and attack foliage. 



Control. Bordeaux mixture, combined with Paris green, or 

 lime-sulfur combined with arsenate of lead, are perhaps the best 

 sprays, acting as repellents, largely. Dusting with air-slaked 

 lime is helpful. 



The Twelve-spotted Diabrotica or Southern Corn-root Worm. 

 These yellowish-green beetles (Diabrotica 12-punctata Oliv.), 

 with twelve black spots on the back and a black head, are prac- 

 tically omnivorous. They feed on a large variety of foliage and 

 flowers, of forage and garden crops. 



Injury. The larvae or grubs feed upon the roots of melons, 

 cucumbers and allied plants. Plants frequently die as a result of 

 attack upon their roots. In the South this is 

 known as the "Southern Corn-root Worm," 

 and it attacks the stalk of corn just above 

 the roots. If it eats to the center of the stalk 

 the "bud" will die; hence it is locally known 

 as the "bud worm" (see page 208). 



Life History. There are two generations. 

 The beetles are among the first insects to ap- 

 pear in the spring, and their life cycle, from 

 egg to adult, occupies from six to nine weeks. 



Bu?i51t? They may be seei1 on clover or alfalfa in the 

 late fall. Figure 249 illustrates the species. 



Control measures are the same as for the striped cucumber 

 beetle. 



The Neat Cucumber Moth or Pickle Worm. This worm, the 

 larva of a yellowish-brown moth (Diaphania nitidalis Cramer), is 

 three-fourths of an inch long. It is greenish or yellowish green in 

 color, with a brown head. The larva bores into the stems and 

 leaves of the cucumber. It takes about two weeks for a caterpillar 

 to attain its full growth; it then spins a thin silken cocoon in a 

 fold of the leaf. The pupal stage requires about a week, and the 

 complete cycle lasts from three to four weeks in midsummer. 

 The winter is passed in the pupal stage, either in the old vine left 

 on the field or in other trash. 



Injury. The larvae hatching from eggs laid on the blossoms 

 usually feed in the blossoms, and six or more may be found in a 

 single squash blossom at one time. Older caterpillars bore into 



