INSECTS INJURIOUS TO CORN. 149 



by the first generation results in serious injury to the crop, 

 preventing the growth of the ears/' 



Description. — When full-grown the larv^ are about 

 three-fourths of an inch long, with six true legs and five 

 pairs of pro-legs, and of a white color marked with brown 

 as shown in Fig. 8*?. These brown markings often become 

 indistinct or lost in larvae hibernating over winter. 



Preve7itive. — Dr. Howard states that "in 1891 it was 

 found that of corn planted during the first and second 

 weeks in April, 25 per cent was damaged; of that planted 

 the third and fourth weeks, 20 per cent was damaged: of 

 that planted May 1st to 15th, 15 per cent was damaged: 

 of that planted May 15th to 31st, 12 per cent was 

 damaged; of that j^lanted from June 1st to 15th, 8 per 

 cent or less was damaged. In fact, corn planted after the 

 first of June was practically uninfested. " 



Remedies. — Where corn has been seriously infested the 

 old stalks or butts should be dragged off the field and 

 burned late in the fall, thus destroying the over-wintering 

 borers. Where corn is stripped for fodder, the stalks left 

 standing, and the land sown in small grain, the most 

 favorable conditions are allowed the borers for safely pass- 

 ing the winter and developing into moths which will fly 

 to new fields in the spring. Besides corn, sugar-cane, and 

 sorghum, this insect also attacks a rank-growing grass 

 which grows upon swampy land, known as Ga ma-grass, 

 or Sesame-grass (Tripsacum dad ylo ides). Where such 

 grass adjoins corn-fields, therefore, it would be well to 

 burn it over in the summer. A simple rotation of crops 

 will also do much to lessen the numbers of this pest. It 

 has been observed by Dr. Howard that crops on fields 

 planted in corn the previous year have been damaged to 



