The risk of classical biological control in Florida

Classical biological control in Florida dates from 1899, when Rodolia cardinalis (Mulsant) was introduced and controlled an infestation of the adventive (=nonindigenous) species Icerya purchasi Maskell. We list 60 invertebrates (59 insects and one nematode) imported into and established in Florida up until and including 2003. No vertebrates have been imported and established for classical biological control. All targets of successful introductions except one were adventive pest insects and weeds. The exceptional target was a widespread aphid, whose introduced biological control agent had no obvious effect. Using many sources of information, we consider the effects, both potential and realized, of established classical biological control agents, on non-target species in Florida. Our goal was to provide a substantiated record and an example analysis. Florida, with high numbers of invasive species, is a microcosm of worldwide classical biological control. We recognized six levels of host range of agents and concluded that 24 agents potentially have native species in their host range. Our analysis suggests that fewer than 10 introduced agents are likely to have produced population changes in non-target organisms and, of these, fewer than four are likely to have produced substantial population changes. No species has had a documented substantial effect on a non-target species in Florida. Such evidence might accrue in future, however, if searched for diligently.