COS 1-6 - Experimental evidence of invasive green iguana (Iguana iguana) impact on crops in Puerto Rico

Abstract: Losses in crop yield due to invasive insects, weeds, pathogens, and herbivores cost trillions of dollars per year globally. To prevent further spread of invasive agricultural pest species, continuous monitoring and prevention are crucial. Once introduced, however, assessing the impact of an invasive pest on agricultural production and testing management strategies are essential. The green iguana (Iguana iguana), a widespread invasive herbivore, is considered a possible agricultural pest although no quantitative data on its impact are available. In this study, we evaluated the impact of the invasive green iguana on cucumber (Cucumis sativus) yield by testing the efficacy of two management strategies – Neem-based pesticide and mesh fencing – compared to open field cultivation in Puerto Rico. Mesh fencing doubled cucumber yield compared to open field cultivation but spraying Neem had no effect on cucumber yield. This study supports categorizing the green iguana as an invasive agricultural pest species and demonstrates the reptile’s potential to reduce crop yield. It also shows that mesh fencing, but not Neem application, is an effective mitigation technique for reducing crop loss from green iguana herbivory. Government agencies in regions where the green iguana has the potential to be introduced should consider the species a threat to food production when developing monitoring programs and drafting regulations.