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

Abstract

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.