﻿12 BULLETIN 1397, U. S. DEPARTMENT OF AGEICULTUEE 



alternative plants have been disregarded, for the reason that most 

 extensive searches have failed to disclose any of the insects in any 

 of the malvaceous plants growing in such zones. Certainly the 

 apparent success of the noncotton zones (and clean-up measures) 

 in eliminating the infestation minimizes the importance of the 

 existence of the pink bollworm on plants other than cotton under 

 such conditions as have prevailed in the United States, It must be 

 remembered that there has never been any heavy infestation of 

 cotton by the pink bollworm. The number of moths produced has 

 in every case been exceedingly small. With a very heavy infestation 

 the results might have been very different, since out of a larger 

 population of moths there might be a sufficient number of aberrant 

 individuals to continue the species on other plants. 



NATURAL ENEMIES 



The pink bollworm has a number of insect enemies wherever it 

 occurs. In the Hawaiian Islands Busck (3) found at least five 

 species attacking it. Other species have been recorded from Egypt, 

 Brazil, and India. In Mexico, early in July, 1921, as high as 33 per 

 cent of the pink bollworm larvse in blooms were killed by parasites. 

 Two species of Hymenoptera, Microbracon mellitm" Say and Ilabro- 

 hracon gelechiae Ashm., were responsible for this unusual destruc- 

 tion. 



By far the most important enemy of the pink bollworm is a small 

 mite known as Pediculoides ventricosus Newport. Its attack is con- 

 fined almost entirely to pink bollworm larvae in stored seed. It is 

 a common enemy of insects and occurs throughout the world. It 

 has apparently increased to a very considerable extent in Egypt, 

 but does not seem likely to be sufficiently abundant at any time to 

 serve as an important agent in controlling the pink bollworm. 

 Neither do the available records indicate that any insect or mite 

 enemies of the pest are likely to be of any practical importance in 

 controlling it. 



It is interesting to note that the mite to which reference has been 

 made also attacks human beings. In 1914 large quantities of Egyp- 

 tion cottonseed were shipped to London. The laborers employed in 

 handling this seed became affected with a rash of the skin caused by 

 the punctures of the mite. The irritation was severe and resulted in 

 a strike for higher wages. The- writer has learned from E, C. Green 

 that in Brazil, since the establishment of the pink bollworm there, 

 children who play about seed houses soon become affected by a 

 dermatitis which probably is the same as that which has been found 

 to follow the attack of the mite in other parts of the Avorld. 



NATURE AND EXTENT OF DAMAGE 



The pink bollworm affects cotton production in several ways. In 

 the first place it destroys a certain number of bolls or portions of 

 bolls, causing the lint from them to be short and kinky, (Fig. 10.) 

 The injury, however, is not limited to the yield and quality of lint. 

 The crop of seed is correspondingly reduced, and what seed is 

 obtained is of light weight and poor grade. In the crushing of 

 Egyptian seed in England it was found that the oil content was 



