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United States Department of Agriculture

Agricultural Research Service

Research Project: RISK ASSESSMENT STUDIES OF CLASSICAL BIOLOGICAL CONTROL OF BRAZILIAN PEPPER

Location: Invasive Plant Research Laboratory

2012 Annual Report


1a.Objectives (from AD-416):
To reduce the invasibility and dominance of Brazilian pepper in agricultural and natural areas of the U.S. through the use of biologically based IPM.


1b.Approach (from AD-416):
Conduct foreign explorations to identify and prioritize potential agents for biological control. Testing will be conducted to determine suitability for safe biological control introductions. Suitability will be determined through feeding/oviposition/developmental trials on related plant species available in South America. Priority will be given to species that show a high level of specificity for the target weed and pose minimal risk to desirable plant species.


3.Progress Report:

This research relates to inhouse Objective 4. Conduct risk analysis to determine environmental safety of new and existing potential biological control agents for weeds such as melaleuca, Brazilian pepper, lygodium, downy rose myrtle, Chinese tallow, waterlettuce and skunk vine.

The health and functioning of the greater Everglades ecosystem is being compromised by the proliferation of invasive exotic species. Brazilian peppertree (Schinus terebinthifolius Anacardiaceae) is acknowledged to be one of the most harmful invasive plant species decreasing biodiversity and proper functioning of the system. The plant presently covers over 280,000 ha in southern Florida alone. No-choice tests of Florida relatives of the weed in the same family were conducted with a prospective agent the thrips Pseudophilothrips ichini to determine risk to the most vulnerable species. Of the 13 species tested, a small number of larvae completed development on Pistacia vera, Metopium toxiferum and Schinus molle (all hosts from no-choice tests). Thrips choice tests were conducted between the weed and these three species. These results indicate that when the adults are given a choice they almost always chose to feed and lay eggs on the weed; a single thrips was found on Metopium in one of the choice tests. Multiple generation tests were initiated and suggest (though still underway) that the thrips will not be able to sustain a population only on these non-target species. Finally, research was initiated to determine if a different thrips population from a more tropical climate had different host specificity. However, results indicate that they constitute a similar threat to Metopium toxiferum, Pistacia vera, and Rhus typhina.


Last Modified: 9/21/2014
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