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MISCELLANEOUS PUBLICATION NO. 10 65, U.S. DEPARTMENT OF AGRICULTURE 



organic chemicals offer a remarkably simple 

 means of detecting insects and possibly of control- 

 ling them, when used in conjunction with insecti- 

 cides or chemical sterilants. 



An attractant for the gypsy moth was synthe- 

 sized several years ago. This substance has been 

 found to be valuable in making surveys of gypsy 

 moth populations and significantly reducing the 

 cost of the surveys. 



Eradication of the Mediterranean fruit fly by 

 the use of a protein hydrolysate bait containing 

 malathion is one of the most significant recent de- 

 velopments. Early programs to eliminate medflies 

 cost millions of dollars; eradication in 1066, at 

 Brownsville, Tex., cost $200,000 and took only 44 

 days from the time the outbreak was discovered. 

 The last eradication effort was aided materially by 

 the use of another attractant, a synthetic chemical 

 called "medlure." The synthetic attractant pro- 

 vided an effective means of detecting medflies so 

 that the bait spray could be applied before the pest 

 had spread over wide areas. 



A bait containing peanut oil and a toxicant, 

 mirex, is now used to control imported fire ant. 

 This bait-insecticide combination permits the con- 

 trol of this insect by the use of only a few grains of 

 insecticide per acre. This bait, which is harmless 

 to fish and wildlife, replaced heptachlor, a per- 

 sistent residue-forming insecticide that created 

 hazards to wildlife. 



Methyl eugenol, a powerful synthetic attractant 

 for males of the oriental fruit fly, can be used in 

 conjunction with an insecticide to eradicate this 

 insect. 



Insect repellents have been used successfully for 

 protecting man from attack by disease-carrying 

 and pest insects. Considerable research on repel- 

 lents for livestock has been conducted with some 

 success. No effective repellents for agricultural in- 

 sects have been found. 



Varieties or strains of plants that are resistant 

 to the attacks of specific insects may be selected or 

 developed. This approach to insect control has 

 been recognized for many years. In 1860, the grape 

 industry in France was threatened by a root-feed- 

 ing aphid from America. The problem was solved 

 by grafting European grapes on resistant root- 

 stock from the United States. The first research on 

 this approach to insect control in the United States 

 was initiated at the Kansas agricultural experi- 



ment station about 1920. In 1928, a sorghum 

 variety resistant to chinch bugs was released to 

 growers. 



Cooperative State-Federal research involving 

 plant breeders and entomologists has developed 

 varieties of wheat that are highly resistant to the 

 Hessian fly, one of the major pests of wheat in the 

 United States. 



Excellent progress has been made in the devel- 

 opment of resistance in field corn to the European 

 comborer. 



Alfalfa varieties have recently been developed 

 that are highly resistant or almost immune to 

 damage by the spotted alfalfa aphid. This intro- 

 duced pest threatened the alfalfa crops in the 

 Western States about 10 years ago. 



Tree resistance to insect pests has been studied 

 by forest entomologists since about 1945. Most in- 

 terest has been focused on developing strains re- 

 sistant to tree-killing bark beetles. Pine oleoresin 

 constituents associated with resistance to the 

 western pine beetle have been identified. This is an 

 important step toward selecting resistant strains. 

 A hybrid pine has been found that is resistant to 

 the pine reproduction weevil. 



Crop varieties resistant to specific insects are not 

 readily attained. Ten or more years of research is 

 usually required to develop a satisfactory strain. 

 Farmers generally need solutions to insect prob- 

 lems as quickly as possible. Research resources are 

 generally inadequate to carry on both immediate 

 and long-range solutions to problems. 



Self-destruction of insects by methods involving 

 sterility and other genetic principles offers a new 

 approach to the control of insects since it was first 

 investigated about 1950. The screw-worm fly, one 

 of the most destructive insect pests of livestock, is 

 now controlled by the release of radioactively 

 sterilized males. This success has increased efforts 

 in exploring the feasibility of inducing sterility to 

 control other major pests. Included are tropical 

 fruit flies, codling moth, boll weevil, pink boll- 

 worm, tobacco hornworm, gypsy moth, locust 

 borer, and the European pine shoot moth. Sterili- 

 zation offers promise as the primary means for 

 controlling certain insects, but its greatest value 

 will be in integrating it with other procedures for 

 controlling insects. 



Research has shown that insect sterilization can 

 be accomplished in three ways — by the use of 



