12 
BULLETIN 1397, U. S. DEPARTMENT OF AGRICULTURE 
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 boll worm 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 larvae in blooms were killed by parasites. 
Two species of Hymenoptera, Microbracon melUtor Say and Habro- 
bracon gelecfdae 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 larva? in stored seed. It is 
a common enenry 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 Egvp- 
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 (h-een 
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 world. 
NATURE AND EXTENT OF DAMAGE 
The pink bollworm affects cotton production in several ways. In 
the first place it destroys a certain Dumber 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 
