ARS | Publication request: Role of Molecular Genetics in Identifying ‘Fine Tuned’ Natural Enemies of the Invasive Brazilian Peppertree, Schinus terebinthifolius

Submitted to: Biocontrol
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 13, 2011
Publication Date: December 9, 2011
Repository URL: http://www.springerlink.com/content/h4m1m266725r3624/
Citation: Cuda, J.P., Christ, L.R., Manrique, V., Overholt, W.A., Wheeler, G.S., Williams, D.A. 2011. Role of molecular genetics in identifying ‘fine tuned’ natural enemies of the invasive Brazilian peppertree, Schinus terebinthifolius. Biocontrol. DOI: 10.1007/s10526-011-9418-y.

Interpretive Summary: Biological control research is being conducted against the south Florida weed Brazilian pepper. This paper reviews the research detailing the genetic diversity of the weed in both its native and exotic ranges and the adaptations of two insect species being considered as biological control agents. These include species of thrips and species of psyllids which specialize on distinct varieties of the weed. A promising thrips, Pseudophilothrips ichini has been under consideration. This thrips was introduced into quarantine in Florida to determine its safety for release. However, a major limitation of the thrips population tested in quarantine was its apparent nutritional incompatibility with the genetic varieties of the host that occur in Florida. Although this thrips was collected on the host in Brazil, its survival was less than 5% when fed the Florida variety of Brazilian pepper. Extensive DNA and morphological analysis of the thrips determined that the quarantined species is incorrectly identified and constitutes a new cryptic species Pseudophilothrips gandolfoi. Similar work is being conducted on a psyllid, Calophya terebinthifolii. As a result of these studies, individuals of both species groups have been correctly identified. These thrips were found feeding on the Florida variety of the weed in Brazil. This review article demonstrates how this technique improves biological control by matching the weed variety with specialized species of insects. Furthermore, the molecular approach increases the number of insect species available for testing and consideration as control agents.

Technical Abstract: Brazilian peppertree is a highly successful invasive species in the continental United States, Hawaiian archipelago, several Caribbean Islands, Australia, Bermuda, and a number of other countries worldwide. It also is one of only a few invasive intraspecific hybrids that has been well characterized genetically. The natural enemy complex of Brazilian peppertree includes two species of thrips and psyllids, respectively that appear to be highly adapted to specific genotypes or their hybrids. Successful biological control of Brazilian peppertree will require careful matching of the appropriate natural enemies with their host plant genotypes. The Brazilian peppertree model described here could provide a useful framework for studying biological control agents on other invasive weed species, especially those that may be hybrids.