Location: Invasive Plant Research LaboratoryTitle: Biology and host range of Omolabus piceus, a weevil rejected for biological control for Schinus terebinthifolius in the USA Author
Submitted to: Biocontrol
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2013
Publication Date: 5/31/2013
Publication URL: http://www.springer.com/home?SGWID=0=0-1003-0-0&aqld=2501609&download=1&checkval=345e7c19278ca5df82c612c05aace701
Citation: Wheeler, G.S., Mckay, F., Vitorino, M., Williams, D.A. 2013. Biology and host range of Omolabus piceus, a weevil rejected for biological control for Schinus terebinthifolius in the USA. Biocontrol. DOI 10.1007/s10526-013-9523-1. Interpretive Summary: The suitability of a new species Omolabus piceus of insect was determined for biological control of the invasive weed, Brazilian pepper, Schinus terebinthifolius. This is a serious environmental and agricultural weed in the USA and elsewhere in the world. At least two weevil species of the Omolabus genus were discovered in South American associated with the host. However, only one of these O. piceus was studied here. The life history of this leaf rolling weevil species and its safety toward native and economic plants was determined in the laboratory with adult no-choice egg deposition and adult consumption tests. Life history results indicated that the larvae this species consumed an average of 11.3 ± 0.4 mg of leaves throughout their development which required 15.1 (± 0.2 d). An average of 31.6 ± 2.7 eggs were laid per female throughout their lifetime (23.8 ± 2.2 d), after a 3.4 ± 1.0 d preoviposition period. To examine safety of this species, eight plant species in the plant family cashew or sumac (Anacardiaceae) were selected based on relatedness to the weed, economic importance, and availability. In the laboratory, except for mango, all of the tested species were accepted for oviposition with a marked preference for the economic species cashew and pistachio and the Caribbean species purple mombin. In conclusion, O. piceus will not be considered for the biological control of S. terebinthifolius in the continental U.S. However, the utilization of this species in other infested areas such as Hawaii and Australia should be considered.
Technical Abstract: Surveys for biological control agents of the invasive weed Schinus terebinthifolius (Anacardiaceae) discovered two Omolabus weevils (Coleoptera: Attelabidae) feeding on the plant in its native range. Molecular and morphological analysis indicated that one of these species consistently fed on the target weed and the other species fed more broadly. Aspects of the biology and host range of the more specific species, Omolabus piceus (Germar) were examined to determine its suitability as a biological control agent of S. terebinthifolius in the USA. Adults feed on newly formed leaves, and eggs, larvae and pupae develop in curled fragments of leaves, called nidi. Larvae consumed an average of 11.3 ± 0.4 mg of leaves throughout their development which required 15.1 (± 0.2 d). An average of 31.6 ± 2.7 eggs were laid per female throughout their lifetime (23.8 ± 2.2 d), after a 3.4 ± 1.0 d preoviposition period. In no-choice tests, O. piceus adults fed and oviposited on all tested native North American, Caribbean and agricultural Anacardiaceae species except for M. indica. The field host-range of O. piceus, as determined by samples of host use in the native range, included three Schinus, two Lithrea and one Anacardium species. Therefore, we do not recommend O. piceus for biological control of S. terebinthifolius in the USA. However, the utilization of this species in other infested areas such as Hawaiì and Australia should be considered.