Effect of host-plant genotypes on the performance of three candidate biological control agents of Schinus terebinthifolius in Florida

Abstract

Brazilian peppertree, Schinus terebinthifolius Raddi, native to South America, is an invasive weed in Florida, California, Texas, and Hawaii. Genetic studies have recognized two S. terebinthifolius haplotypes (A and B) in Florida, and extensive hybridization has occurred between these two populations. Three candidate biological control agents were identified from the native range (Brazil); a leaflet rolling moth Episimus utilis Zimmerman, a thrips Pseudophilothrips ichini Hood from Ouro Preto, and an unindentified thrips, referred to as Pseudophilothrips sp. near ichini, from Curitiba, Brazil. The objective of this study was to compare the performance of these three candidate agents on different S. terebinthifolius genotypes found in Florida and Brazil. Survival (54%), adult longevity (9 days), fecundity (84 eggs laid), and fertility (68% eggs hatched) of E. utilis were similar on all S. terebinthifolius genotypes tested from Florida. In contrast, the two thrips species differed in their ability to utilize different genotypes of their host plant. Pseudophilothrips sp. near ichini exhibited low survival (0–4%) and short adult longevity (<10 days) when reared on Florida genotypes, whereas higher survival (∼50%) and longevity (∼30 days) were observed for P. ichini on these genotypes. These findings highlight the importance of examining insect performance on plant genotypes present in the introduced and native ranges when selecting biological control agents. The ecological significance of the results is discussed in the context of plant genotypes and possible local adaptation of their natural enemies.