254 INSECT PESTS OF FARM, GARDEN AND ORCHARD 



The Cotton Bollworm * 



One of the most destructive and widespread pests of cotton is 

 the bollworm, the same insect as the earworm of corn already 

 described (page 181), which should be consulted for the life history 

 and description. Throughout the cotton belt the moths of the 

 third generation appear about August 1st. At that time the ears 



of corn have become too 

 hard to furnish suitable 

 food for the larva? and 

 the moths therefore lay 

 their eggs on the cot- 

 ton leaves, though if 

 any late corn is in silk 

 it is decidedly preferred. 

 Thus during the month 

 of August the cotton is 

 often seriously injured 

 by the caterpillars bor- 

 ing into the bolls, this 

 injury being most seri- 

 ous in recent years west 

 of the Mississippi and 



particularly in north 

 I<iG.l<S2. Bollworm at work on cotton bolls, bor- * 



ing into grown boll slightly reduced. (After Texas and Louisiana. 

 Qua:ntance and Brues, U. S. Dept. Agr.) The total damage to cot- 



ton is estimated at upward of $20,000,000 per annum. Though 

 more or less damage is done by the fourth generation of worms, 

 injury is rarely serious, as the numbers are greatly reduced 

 by parasites and unfavorable weather conditions. 



About two-thirds of the eggs on corn are parasitized by 

 a tiny little insect hardly visible to the naked eye,f which 



* Heliothis obsolete. Fab. Family Noctuidtt. See Farmers' Bulletin 

 No. 290, U. S. Dept. Agr., by F. C. Bishopp and C. R. Jones and Bulletin 50, 

 Bureau of Entomology, U. S. Dept. Agr., by A. L. Quaintance and C. T. 

 Brues. 



t Trichogramma pretiosa Riley. 



