COTTON INSECTS 



391 



injury done to cotton, prevention or poisoning is seldom 



attempted. Experiments have shown that dusting the 



plants with a light application of Paris green or other 



preparation of arsenic destroys many of the tiny worms 



on the day on which they are hatched and before they are 



large enough to enter the 



boll. For poisoning to be 



most effective, it should begin 



about the time that adjacent 



corn ears begin to harden, and 



it may need to be repeated 



several times. The poison 



adheres better if applied while 



the dew is on the plants. 



The most generally practi- 

 cable method of reducing the 

 injury to cotton consists in 

 using corn as a trap crop. 



Strips of corn should be planted about the first of June, 

 or at such times as to bring the corn into the roasting-ear 

 condition about the first of August. Then the moths 

 deposit their eggs on the corn rather than on the cotton 

 plants. The trap crop of corn is still more effective if two 

 plantings are made at intervals of a few weeks, so as to 

 furnish a continual supply of roasting ears during the 

 time when moths are most numerous. These strips of 

 corn may be planted on oat patches adjacent to the cotton 

 fields, or better, 2 to 4 rows of corn may be planted in 

 alternation with 20 to 40 rows of cotton. In order for 

 the corn to serve as a trap crop, it must be planted late, 

 and not at the time when the cotton is planted. 



FIG. 169. PUPAL OR CHRYSALIS 

 STAGE OF THE COTTON BOLL- 

 WORM OR CORN EAR-WORM. 



