An “invasive species” generally refers to an “alien” or “non-native” species that arrives in a new habitat or country, becomes established, and spreads and proliferates to such an extent that it causes one or more types of damage. Many different types of organism can be invasive. In this paper we illustrate some of the issues and approaches in responding to the threat of invasive species, using examples of CABI’s work on the Fall Armyworm (FAW). The pathway by which an invasive species reaches a new area is usually connected to human activity. Significant numbers of invasive species, including many plants but also some invertebrates and vertebrates, are introduced intentionally with some purpose or use in mind. The introduction also occurs unintentionally through contamination of commodities, shipping containers and other items that are moved long distances. The pathway by which FAW escaped from its native area in the Americas to become widely established in Africa, Asia, and the Pacific is not known, and there is evidence that more than one such introduction may have occurred. However, in considering the appearance of FAW in West Africa, Cock et al. (2017) concluded that it was most likely FAW arrived as a stowaway, or possibly as a commodity contaminant. Prior to its appearance in Africa in 2016, FAW had been regularly intercepted arriving in Europe on commodities such as Capsicum and Solanum imported from Central and Southern America, providing evidence that commodity shipments are a potential pathway of introduction.

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