Native range efficacy assessment of Calophya terebinthifolii, a candidate biological control agent of Schinus terebinthifolia in Florida, USA

Background: Aroeira or Brazilian peppertree, Schinus terebinthifolia Raddi (Anacardiaceae: Rhoeae), is one of the worst invasive plants in California, Florida, and Hawaii, USA because of its wide distribution, adaptation to various habitats, toxicity, and demonstrated negative impacts on biodiversity. Chemical and mechanical methods provide only temporary control, are expensive, may damage native plants, and often create disturbance conducive to reinvasion by Brazilian peppertree and other invasive weeds. The leaflet galling psyllid Calophya terebinthifolii Burckhardt & Basset (Calophyidae: Calophyinae) is native to South America and recent studies have shown this insect attacks only Brazilian peppertree. Nymphs complete their development in open pit galls that create nutrient sinks, which divert resources away from normal plant growth and reproduction. Objective: The objective of this study was to confirm the biological control potential of C. terebinthifolii. Methods: We used a randomized complete block design with four treatments (chemical exclusion [control], natural infestation, low and high psyllid densities) replicated in space. Results: At low densities, C. terebinthifolii significantly reduced flower production by 80.6% and 93.9%, respectively, compared to the chemical exclusion treatment. At high densities, the psyllid completely inhibited fruit production. Furthermore, leaf and stem biomass were significantly reduced following sustained attack by the psyllid C. terebinthifolii. Conclusions: Overall, our results confirmed that feeding damage by this psyllid negatively impacts above ground vegetative growth and reproduction of Brazilian peppertree. Therefore, C. terebinthifolii should be considered for introduction into Florida for biological control of this invasive shrub.