Invasive Insect Pests: Challenges and the Role of the Sterile Insect Technique in Their Prevention, Containment, and Eradication

Abstract

886The rapid expansion of international travel and trade are facilitating the spread of non-native species, while climate change is creating new ecological niches enabling the establishment of pests in previously inhospitable regions. The temporary large-scale application of insecticides and “scorched earth” approaches are often indispensable to deal effectively with such outbreaks of invasive pests. However, even when the political will is there to implement the required systematic eradication efforts, they often result in public resistance to drastic actions such as the destruction of infested crops, herds, and orchards, and the indiscriminate insecticide spraying that raises concerns about damage to the environment and human health. Furthermore, such campaigns can still fail to achieve final eradication of all remnants of incipient populations. Therefore, and also in response to the enactment of environmental laws and regulations, increased efforts are needed to develop new and effective early detection and eradication tools that can prevent the establishment of a new pest in a less disruptive and more environment-friendly way. The sterile insect technique (SIT) is a proven method to prevent, contain, and eradicate outbreaks of invasive insect pest populations. It is an effective and ecology-friendly method that, unlike insecticides and other control methods, acts in an inversely density-dependent manner, and as a result increases its efficiency with decreasing population density. Therefore, it is particularly well-suited to eliminate incipient invasive-pest introductions and outbreaks when applied as part of an area-wide integrated pest management (AW-IPM) approach. When flooding a target pest population with sterile males, the wild virgin females (that are not controlled with other methods) are actively located and mated by the sterile males, producing no offspring. Some examples of eradication include incipient invasive populations of the painted apple moth Teia anartoides Walker in New Zealand, and the cactus moth Cactoblastis cactorum (Berg) in Mexico; major outbreaks (Cochliomyia hominivorax (Coquerel) in Libya); and all the way to fully established invasive pest populations (pink bollworm Pectinophora gossypiella (Saunders) in the southern USA and northern Mexico, and melon fly Zeugodacus cucurbitae (Coquillett) in the archipelagos of southern Japan). The SIT is also being used to contain invasive pest populations, such as Ceratitis capitata (Wiedemann) in southern Mexico, and preventively by releasing sterile insects over areas with a historically high risk of invasive pest incursions (C. capitata in California and Florida). There is great potential to expand the SIT application to similar situations against other major invasive insect pests. This chapter compares some eradication campaigns in the pre-SIT era with those integrating the SIT to eradicate, contain or prevent the establishment of non-native insect pests, and discusses the constraints and needs for contingency planning, including a proactive approach to develop the SIT package for other potential major invasive insect pests.