Helicoverpa armigera invading the Americas
Helicoverpa armigera larva in maize (Photo Tek Tay, CSIRO)
Helicoverpa armigera has recently been discovered in South America.  It has since been tracked spreading into the Caribbean.  Pest risk modelling has revealed that most of the US crop production may be at some degree of risk from this pest, which has developed resistance to most pesticides.  The rapid northward spread in the Americas suggests that it is now a matter of when, rather than if it will invade the USA.  The pest risk research has been published in PLOS One.
The current and potential distribution of Helicoverpa armigera