INSECTS INJURIOUS TO SWEET CORN 201 



The different species of this genus of which there are many 

 seem to agree in transformation to pupse in the larval burrow, 

 the last act of the larva before making its final moult being 

 the construction of a large opening about one-fourth inch in 

 diameter for its escape when the moth condition is attained. 

 The pupal period lasts from two to four weeks and the moths 

 issue sometime in September or October. 



Remedies. — In ordinary cases this stalk-borer can be held in 

 check in the small vegetable garden which it has invaded by 

 pulling and burning infested plants. As the moth lays her eggs 

 on the stems in September, fall plowing is advisable, or raking 

 up and burning all forms of vegetation, especially ragweed. 



In large fields it is difficult to combat, but its injuries may be 

 prevented by care in keeping down, and by promptly destroying, 

 the weeds after they are pulled or hoed out during the .growing 

 season. If weeds are left to dry the striped caterpillar of this 

 species will desert them and enter cultivated plants. Crop rota- 

 tion is advisable where this can be conveniently practiced, and 

 such plants as cabbage, radish and the like, onions, beets, 

 asparagus and' celery are suggested as alternates. When the 

 plants are sprayed with arsenicals for other insects this will 

 operate to a certain extent against this stalk-borer. 



Owing to the frequency of attack on the borders of culti- 

 vated fields, it might be found a measure of some value to per- 

 mit the ragweed to grow at these points as lures to the in- 

 sects, and destroy them before September, i. c, before the moths 

 have issued to lay their eggs for another generation. Fall 

 plowing should be practiced or the fields burned over late to de- 

 stroy the eggs. 



The Larger Corn Stalk-borer {Diatrcea saccharalis Fab.). — 

 This pernicious corn pest, although a southern insect, in a 

 succession of seasons which favor its development sometimes 

 works northward as far as Delaware and New Jersey, where it 

 is occasionally-injurious, and westward to Kansas. It is identical 



