138 , FIELD CROPS FOR THE COTTON-BELT 



or more generations of this insect during a growing season, 

 two or three of which are very destructive. 



166. Damage. — It is the caterpillar stage which 

 causes the damage to cotton. While very young these 

 caterpillars feed only on the underside of the leaf on which 

 they hatch. Later they move toward the top -of the plant, 

 eating the more tender foUage. After the caterpillars are 

 five to seven days old the rate of destruction is very rapid, 

 depending of course on the number present. Often an 

 entire field of cotton is completely stripped of its leaves 

 within two to five days. This pest is worse in imusually 

 wet seasons. 



167. Means of control. — Owing to its feeding habits, 

 the cotton leaf-worm is easily controlled by dusting an 

 arsenical poison Ughtly over the top of the cotton plants. 

 The same method is employed as recommended for the 

 cotton boll-worm. For average cotton, three pounds of 

 "powdered" arsenate of lead will poison an acre. If the 

 cotton is rank, more poison will be necessary. One good 

 dusting should be given at the beginning of each crop of 

 worms. No time should be lost in applying the poison 

 after the first damage is noticed. 



INSECTS OF SECONDAHY IMPORTANCE 



168. The cotton leaf-louse. — This is a small green 

 louse often found in great' numbers on the tender parts 

 of young cotton plants. In cool seasons this insect does 

 much damage to cotton by sucking the sap from the 

 plants. It usually disappears when settled hot weather 

 comes. 



No thoroughly practical method is known for destroy- 

 ing the cotton leaf-louse. Any insecticide that kills by 

 contact would destroy this pest, yet the practicability 



