INSECTS INJURIOUS TO COTTON 



243 



yet as a rule their use on any considerable scale will hardly be 

 profitable. Keeping the fields clear of weeds by fall and winter 

 plowing will undoubtedly have a beneficial effect in reducing 

 the numbers of aphides and in most cases will be the only treat- 

 ment necessary. 



The Cotton Worm * 



Until the advent of the boll weevil, the cotton worm was 

 much the most serious insect pest of cotton. Since then, however, 

 its importance has been rather overshadowed in the mind of the 



FIG. 174. Pimpla conquisitor, one of the principal parasites of the cotton- 

 caterpillar: a, larvae enlarged; b, head of same still more enlarged; 

 c, f pupa ; d, adult female enlarged ; e, f, end of abdomen of adult male, 

 still more enlarged. (From Fourth Rept. U. S. Entom. Comm.) 



planter by the onslaught of the invading Mexican pest and where 

 the boll weevil is abundant the stripping of the late foliage by 

 the cotton worm really aids in the control of the weevil, as will 

 be explained later. 



Life History. During the winter months the adult moth 

 hibernates in the most southern portion of the cotton-belt, in the 

 rank wire-grass occurring in the more thickly timbered regions. 

 Only a few of these survive, but they are very capable ancestors. 

 In early March they lay eggs upon volunteer cotton when it is 



* Alabama argittacea Hubn. Family Noctuida. 



