Is the stem boring weevil Apocnemidophorus pipitzi (Coleoptera: Curculionididae) host specific to Schinus terebinthifolia (Sapindales: Anacardiaceae)?

ABSTRACT

Brazilian peppertree, Schinus terebinthifolia Raddi (Anacardiaceae), is an ornamental shrub from South America that is invasive in Florida, California, Hawaii and Texas, USA and has become a global invader. Exploratory surveys were conducted in Argentina, Brazil, and Paraguay to discover natural enemies as possible biological control agents. One of the insects collected was subsequently identified as the stem boring weevil Apocnemidophorus pipitzi (Faust). The weevil was found at several localities in Paraguay in April 2007 and transported to Florida, USA, for biological and host range studies. Laboratory no- choice, and multiple-choice tests were performed to determine if A. pipitzi was suitably host specific for release as a biological control agent of Brazilian peppertree in Florida. In total, 79 North American plant species in 40 families and 28 Orders were tested. In the no-choice tests, complete development was significantly higher on Brazilian peppertree, Hardee peppertree, Schinus polygama (Cav.) Cabrera & I.M. Johnst., the invasive ornamental Chinese pistache, Pistacia chinensis Bunge and cultivated pistachio nut, Pistacia vera L. Both Pistacia spp. are chemically related to Brazilian peppertree. However, when given a choice, the stem boring weevil A. pipitzi reproduced only on Brazilian peppertree and the invasive congeneric Hardee peppertree. Overall, results of laboratory host range testing showed the stem boring weevil A. pipitzi is a Schinus specialist. This finding is consistent with field observations, museum records, and the preference-performance hypothesis, where larval survival, growth and normal development are maximised on plants selected for oviposition by the females.

KEYWORDS:

• Brazilian peppertree
• invasive weed
• risk assessment
• weed biocontrol

Acknowledgements

We thank Kenia Duran Aguirre, Michael Arvin, Brendan Bennett, Alissa Berro, Paulo Bertolla, Devon Donahue, Flavia Vaduva, Tanya Stevens, and Rachel Watson for assistance with maintenance of plant and insect colonies and data collection; Jane Medley for providing some of the figures.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Geolocation information

The initial shipment of A. pipitzi adults was collected near Pirapó, Paraguay (26° 51′ 18.96″ S, 55° 32′ 28.89″ W).

Additional information

Funding

This work was supported by The University of Florida Agricultural Experiment Stationt; the Florida Fish and Wildlife Conservation Commission (formerly Florida Department of Environmental Protection) under grant number 107428; The Florida Exotic Pest Plant Council, and the South Florida Water Management District under grant number UPN00012002.