TROPICAL FRUIT-FLY MENACE — CHRISTENSON 445 



In a large-scale test of this male annihilation method on an isolated 

 group of islands in the Western Pacific, conducted by the U.S. De- 

 partment of Agriculture, with the U.S. Navy distributing the pois- 

 oned lure on small pieces of cane fiberboard from a flying boat, and 

 the Trust Territory of the Pacific Islands furnishing laboratory fa- 

 cilities on Guam, near extinction of the oriental fruit fly was achieved. 

 Interruptions in treatment schedules probably prevented eradication. 

 Even though the fly was not eliminated, suppression of the popula- 

 tion density to only about 30 flies or so per 1,000 trap days at one 

 point in the experiment, in contrast to the many thousands of flies 

 caught before treatments were started, was a noteworthy accomplish- 

 ment. The results provided assurance that use of frequent traps 

 baited with methyl eugenol in southern California, where three orien- 

 tal fruit flies were found a few years ago, was a sound procedure. 

 It is unlikely that any infestation present would have been able to 

 expand or develop. 



Although no specific compound comparable in effectiveness to 

 methyl eugenol has been foimd for the Mexican fruit fly, which 

 causes quarantine and control problems along our border with Mexi- 

 co each year, the best attractants found for this fruit fly are ferment- 

 ing or protein hydrolysate liquid mixtures, to which both sexes re- 

 spond. Although thus far only moderately effective, these lures have 

 had significant usefulness by providing effective detection systems in 

 regulatory and eradication programs. 'Wliether they will eventually 

 prove to be strong enough to have direct control usefuhiess remains 

 to be determined. 



Now let us turn for a moment to insecticides for tropical fruit-fiy 

 control. There are individuals who take every opportmiity to con- 

 demn insecticides, but without them, production of adequate supplies 

 of food would be difficult in our country. Insecticides must satisfy 

 stringent safety requirements before they can be registered for sale. 

 Harmful amounts on or in foods are not tolerated, and any material 

 that is even remotely suspected of being able to cause cancer or other 

 diseases, on the basis of acceptable evidence, is quickly banned. Prob- 

 ably nowhere in the world today is there a more healthful and abund- 

 ant variety of food than that present in our markets. 



Entomologists hope that someday it will be possible to grow plants 

 and livestock without insecticides, not because they consider insecti- 

 cides to be a hazard to public health when used properly, but because 

 pests frequently develop resistance to such treatments, the work of 

 beneficial parasites and predators may be interfered with, and residue 

 and application problems are associated with their usage. The de- 

 velopment of less objectionable insecticide treatments and nonchemi- 

 cal methods for insect control has occui)ied high priority in the 

 research on tropical fruit flies for many years. 



