38 



CHAPTER V. 

 Insect Pests of Crops. 



COTTON. 



THE COTTON WORM (Alabama aryillacea Hiibn.) 

 Lepidoptera. 



The cotton woun is an insect native to tropical America, 

 and has I een known ever since cotton has been culti- 

 vated in these regions. It occurs in all the West Indian 

 Islands ; but in St. Vincent alone, it has not occurred in 

 sufficient numbers to canse any damage since the re-estab- 

 lishment of the cotton industry some nine or ten years ago. 

 In the other islands, notably Barbados, Montserrafc, Antigua, 

 Nevis and St. Kitts, this pest has been so abundant at times 

 that fields of cotton have been completely defoliated So 

 rapid is the feeding by the nearly full-grown caterpillars 

 that many persons have believed that the attacks develop in 

 a night ; the caterpillars had not been observed in their 

 younger stages, and it was thought that they were able 

 to reach enormous numbers in this short time. 



The cotton worm occurs in all the cotton-growing dis- 

 tricts of tropical and sub-tropical America, and in the adult 

 stage has been found far outside these limits. No other 

 food plant than cotton is known, and it therefore does not 

 breed in any locality where this plant cannot be grown. 



The Egg. The eggs are laid on the under side of the 



Fig. 34. Eggs of cotton worm. 



(a) seen from above; (b) from the side. Greatly enlarged. 

 (From U.S. Dept. Ayric.) 



