seemed that DDT was the long-awaited answer the fruit grower wanted. However, several 
important side problems emerged which are typical of similar developments resulting 
from the use of insecticides on other crops. The regular use of DDT in orchards led to 
an increase in mites and certain other pests because of the destruction of their natural 
enemies. DDT-resistant strains of the codling moth appeared after 8 to 10 years of use. 
Although DDT residues in relation to apples as a human food posed no serious problem, 
they have created a special problem in relation to the use of apple pomace as a livestock 
feed. DDT levels, in the range of 5 to 7 p.p.m. on fresh apples, will lead to levels in the 
pomace up to 25 p.p.m. or higher after extraction of apple juices. Pomace has been used 
to some extent as a feed for dairy and beef animals but such use must be discontinued. 
Thus, apple pomace has become a liability rather than an asset in the processing of 
apples. This is just one example of the many ramifications of the residue problems that 
could be cited. Substitute insecticides for codling moth control have been developed 
through the efforts of State, Federal, and industry workers that can obviate this residue 
problem. However, substitute insecticides may have both advantages and disadvantages. 
They may avoid residues in the pomace but may be more harmful to certain beneficial 
insects, to fish and wildlife, or be more costly. It is not a simple matter to find and 
develop an effective substitute insecticide that meets all of the standards desired. 
A few outstanding advances have been made in the use of attractants for fruit insect 
control. As an outgrowth of basic studies on the nutritional requirements of fruitflies 
conducted cooperatively by the California Agricultural Experiment Station and the Hawaii 
Fruit Fly Laboratory of the Entomology Research Division, a protein hydrolysate bait 
spray was developed for eradication of the Mediterranean fruitfly in Florida in 1956 and 
1957. The Hawaii laboratory has also cooperated with the Division’s Pesticide Chemicals 
Research Branch in the development of a number of highly active male lures for the 
Mediterranean, melon, and oriental fruitflies. A highly effective oriental fruitfly lure, 
methyl eugenol, has been studied extensively by the Hawaii laboratory and plans are now 
under way to attempt eradication ofthis insectfrom one of the Pacific islands by destroy- 
ing all of the males attracted to this lure. 
Aside from the possible use of lures for direct control of fruitflies, they are es- 
sential as a means for detecting low level infestations of fruitflies, as was demonstrated 
in the successful Mediterranean fruitfly eradication program in Florida. 
COTTON INSECTS 
Much has been said about the importance of insects in the production of cotton. The 
benefits derived from the use of insecticides to control cotton insects are well known to 
the cotton grower. 
For the last 20 to 37 years yield records have been obtained at Florence, S. C., 
Tallulah, La., and Waco, Tex., in untreated experimental plots and similar plots treated 
with insecticides. Since the new insecticides came into use which control a wide variety 
of cotton pests as well as the boll weevil, the yields in treated plots have averaged about 
50 percent increase over check plots. 
The boll weevil is the most important pest in the main Cotton Belt, but it does not 
occur or is not a factor incotton production in the Western States. However, experimental 
plots in Arizona consistently show substantial increases in yield through the use of in- 
secticides for the control of plant bugs, cabbage loopers, salt marsh caterpillars, thrips, 
and other cotton pests. The Arizona Agricultural Experiment Station has shown an interest- 
ing correlation between the steady increase in yields of cotton per acre during recent 
years and the amount of insecticide applied per acre. 
In the production of cotton and a number of other crops, many advances have been 
made during recent years in soil and water management, use of fertilizers, high-yielding 
varieties, and disease control. Cotton insect control alone will not assure high yields of 
cotton. However, maximum potential in cotton production efficiency cannot be realized 
without good insect control. In fact, practices which are essential for high yields may 
greatly intensify cotton insect problems unless adequate control measures are applied. 
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