The sterile insect technique (SIT) is an environmentally friendly method for the biological control of pests using area-wide inundative release of sterile insects to reduce reproduction in a field population of the same species (IPPC, 2007). SIT technique may be applied as part of an area-wide control (integrated pest management) approach of insects of medical, veterinary, and agricultural importance. It was in 1937 when Edward Knipling proposed using sterilization to control or eradicate insect pests after observation that screwworm fly males mate repeatedly while females mate only once. He then made the hypothesis that if large numbers of sterile males could repeatedly be released into wild populations, it would eventually eliminate population reproduction and lead to eradication.[1] [2] [3]
This table is a list of sterile insect technique trials worldwide.
| Target | Year | Location | Method | Outcome | |
|---|---|---|---|---|---|
| Tanzania | Release of Glossina morsitans centralis into a Glossina swynnertoni population | Hybrid males were sterile and the female hybrids partially sterile. 99% suppression in 26 km2[4] [5] | |||
| Cochliomyia hominivorax | United States | Release 39 sterile male flies per km2 per week for several weeks | Field evaluation pilot test. Resulted in up to 100% sterility of the egg masses, greatly reduced the wild population, incomplete eradication because of the wild fertile flies flying from the mainland.[6] | ||
| Cochliomyia hominivorax | Netherlands Antilles Curaçao (435 km2) | Released 155 sterile males per km2 per week | 100% egg sterility after 2 generations. Evident eradication was accomplished within 14 weeks. Releases were stopped after 22 weeks.[7] | ||
| Cochliomyia hominivorax | United States | Release 155–1160 sterile flies per km2 per week | Eradication. Total cost was $11M, about 50% of the annual losses.[8] | ||
| Cochliomyia hominivorax | United States Texas and western states | Release 200–1000 sterile flies per km2 per week | Declared eradication in Texas and New Mexico in 1964 and in the entire USA in 1966. Thereafter, the program goal changed to population containment from the initial eradication | ||
| Cochliomyia hominivorax | Central America | Sterile flies release | Declared eradication in Mexico, 1991, Guatemala, 1994, El Salvador 1995, Honduras 1996, Nicaragua 1999, Costa Rica 2000, Panama, 2001 | ||
| Cochliomyia hominivorax | Libya | Release 40 million sterile flies per week | Operated by a joint FAO/IAEA Division. Only 6 instances of wounds infested with screwworm larvae were found in 1991, compared with more than 12000 cases in 1990. Eradication was declared in June 1992[9] | ||
| United States | For eradication, release 96,000 and 61,500 sterile flies per km2 per week in CA and TX, respectively | Started to eradicate in CA in 1964 and to exclude in TX a decade later. Continued as containment program[10] | |||
| Bactrocera tryoni | Australia | Released 1600 million sterile flies in 1990. For containment method, release 60,000 sterile flies per km2 for 12 weeks after catching the last wild fly. | Field trials began in 1962. Population was suppressed strongly, but not eradicated because of long-range immigrants. Eradication was achieved in Western Australia in 1990. Since the mid-1990s, it has been used as containment method.[11] | ||
| Ceratitis capitata | Produced 500 million and 3,500 million sterile flies per week in Mexico and Guatemala, respectively | First large-scale fruit fly AW-IPM program using SIT. Eradication in 1982. For over 25 years, this program kept Mexico, the US, and half of Guatemala free of the pest. Genetic sexing strains were later introduced.[12] [13] | |||
| Japan | Released up to 4 million sterile fly pupae per week, total 264 million during the pilot test. Total 50,000 million sterile flies were released. | A pilot experiment began in 1972 and eradication was declared in 1978. An operation program started in 1984. Complete eradication achieved in 1993.[14] | |||
| Ceratitis capitata | Israel | Released males | Genetic sexing strain[15] | ||
| Ceratitis capitata | United States | Release sterile males of the tsl sexing strain VIENNA 7 | Started as eradication program. It was successful and cost-effective and thereafter (1996) applied as a permanent preventative program in CA, FL, and Guatemala.[16] [17] [18] | ||
| Ceratitis capitata | Jordan-Israel-Palestine | Released genetic sexing strain VIENNA 7 | As population suppression rather than eradication[19] | ||
| Netherlands | Sterile insects are provided from a private source | The program has not been able to expand beyond 16% of the onion production area due to free-riders. Ongoing long-term suppression program over 20 years[20] | |||
| Burkina Faso (3,000 km2), Nigeria (1,500 km2) and Tanzania (1,650 km2) | Combination method with attractant traps and insecticides | Eradication[21] [22] [23] | |||
| Uganda | Autosterilization of wild flies | Suppression[24] | |||
| Anopheles quadrimaculatus | United States | Release adult males after sterilizing in pupal stage. 430,000 males over 48 wks at 2 locations | Poor competitiveness. No population reduction.[25] | ||
| Culex quinquefasciatus | Myanmar | Release 5000 daily for 9 wks. Sterility from cytoplasmic incompatibility | Population eliminated[26] | ||
| Culex quinquefasciatus | United States | Release 930,000 males over 12 wks after chemosterilization with thiotepa | Population suppressed and eliminated partially due to the sterile males released[27] | ||
| Culex pipiens | Release hundreds of thousands over 8 wks after sterilizing with chromosome translocation | Population reduced due to the persistent translocation[28] | |||
| Culex quinquefasciatus | India | Release 300,000 sterile males daily over 14 wks, total 23 million. Sterilization with cytoplasmic incompatibility, and chromosome translocation. | Population reduced due to the established sterility from cytoplasmic incompatibility and translocation.[29] | ||
| Culex quinquefasciatus | India | Release total 38 million sterile males over 25 wks. Chemoterilization with thiotepa. | Up to 90% sterile eggs, but no clear population suppression due to immigration[30] | ||
| Aedes aegypti | Kenya | Release 57,000 genetically modified males over 10 wks. Sterilization with chromosome translocation | Partial sterility, but no long-term persistent translocation[31] | ||
| Anopheles albimanus | El Salvador | Released 4.4 million sterile males over 22 wks. Chemosterilization of genetic sexing strain pupae with bisazir. | 100% sterility induced in wild population. Well below detection level after 5 months.[32] | ||
| Anopheles albimanus | El Salvador Pacific coast | Released 100s million males. Bisazir sterilization. Use genetic sexing strain (MACHO). | Target field population was reduced by 97%, but eradication prevented by unexpected immigration.[33] | ||
| Culex tarsalis | United States | Released 85,000 males over 8 wks after sterilizing with adult irradiation | Assortative mating was observed, but no population reduction.[34] | ||
| Cockchafers | Switzerland | Released 3,109 and 8,594 males after radiation sterilization. | Field trials. The population was reduced by 80% and 100%.[35] | ||
| United States | Combined methods of insecticide and SIT | Large pilot field experiment. Population was suppressed below detection levels in 203 of 236 fields. The remainder were close to uncontrolled area (less than 40 km).[36] | |||
| Japan | Released sterile weevils after insecticide application. | Complete eradication[37] | |||
| Canada | Released irradiated codling moths | As a population suppression method[38] | |||
| Aedes albopictus | Reunion Island | Semi field condition test using the sterilizing dose of 40 Gy with cesium-137 irradiator | two-fold reduction of the wild population's fertility[39] | ||
| Aedes aegypti | Queensland, Australia | Released >3 million males sterilized with the natural bacteria Wolbachia | 80% reduction of the population in trial areas[40] [41] |