Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: May 20, 2004
Publication Date: November 28, 2005
Citation: Mangan, R.L. 2005. Population suppression in support of the sterile insect technique. In: Dyck, V.A., Hendrichs, J., Robinson, A.S., editors. Sterile Insect Technique - Principles and Practice in Area-Wide Integrated Pest Management. Netherlands: IACA Springer Publication. p. 407-425.
Interpretive Summary: Management or eradication of insect pests by sterile insect technique (SIT) depends upon overflooding the pest population with sterile insects. Overflooding can be achieved by two means. Sufficient sterile insects can be reared so that the pest population is overflooded or the pest population can be reduced so that the pest is overflooded with a smaller number of sterile insects. One of the major uses of supplementary population control is to reduce the pest population to achieve overflooding. However, management by sterile insects usually requires several generations for successful reduction of pest population. During this period, sterile insects do not offer protection from damage caused by adult insects or from immature stages of insects that are previously mated. Feeding damage, biting and vectoring of diseases, quarantines and other impacts will continue if actions are not taken to directly reduce the pest population. Pest species that cause damage sufficient to justify a sterile insect management program usually have an array of options for control of the population or to limit damage. Cultural or mechanical control options include environmental modifications to remove breeding sites, management of hosts to preclude breeding or other environmental modifications that act to reduce the populations. The most common method of control is through chemical pesticides. These may include insecticides broadcast over the whole pest population or directed specifically at sites preferred by the insects for feeding or breeding. Trapping as a means of population reduction has also been attempted. Chemical treatments to hosts such as wound treatments for screwworms, treatments of bednets or house treatments against mosquitoes, and pour on treatments to protect livestock from biting tsetse flies have successfully reduced damage from the pest populations. Development of baits has reduced the volume of insecticides and toxicity of insecticides used. Supplementary treatments to reduce the pest population in order for SIT to successfully function requires that application be over the entire range of the pest population or that barriers to migration be established. When supplementary pest control activities benefit the human population in areas being treated, such as in mosquito or screwworm eradication programs, these activities are usually acceptable to the public. When programs are applied and the public receives no benefit, as in fruit fly eradication, social resistance may develop.
Suppression or eradication of insect pest populations by release of sterile insects (SIT) is dependent on over-flooding the target pest population with sterile insects. Population suppression activities usually coincide with production of sterile insects. The pests that have been targets for sterile insect release have been pests of high medical and economic importance. Supplementary methods to remove breeding opportunities or management methods that prevent access of pests to the hosts may reduce the population or prevent damage. Insecticides have been widely used as either broadcasts or applied as baits, in traps, or on specific sites where the pest makes contact or reproduces. Sterile insect release does not kill the pest and adult biting pests or fertile mated pests will continue to attack hosts after release of sterile insects. Supplementary programs are essential in preventing damage, quarantines or spreading diseases during the period of eradication. Eradication or effective management of the pest requires that the entire population of the pest be treated or that the program apply barriers to immigration. When supplementary pest control activities benefit the human population in areas being treated, such as in mosquito or screwworm eradication programs, these activities are usually acceptable to the public. When programs are applied and the public receives no benefit, as in fruit fly eradication, social resistance may develop.