Host specificity of Metriona elatior, a potential biological control agent of tropical soda apple, Solanum viarum, in the USA

The leaf beetle Metriona elatior from Brazil-Argentina was screened in the Florida (USA)State quarantine facility as a potential biological control agent of tropical soda apple, Solanum viarum, a recently arrived weed species. Multiple-choice host-specificity tests were conducted in small cages (60 cm × 60 cm × 60 cm) using 95 plant species in 29 families. Adults fed heavily on the main target weed (S. viarum), and on turkey berry,Solanum torvum (noxious weed of Asiatic origin); fed moderately on red soda apple, Solanum capsicoides (weed of South American origin), and eggplant, Solanum melongena (economic crop); and fed lightly on aquatic soda apple, Solanum tampicense (weed of Mexican-Caribbean-Central American origin), and onsilverleaf nightshade, Solanum elaeagnifolium(native weed widely distributed). M.elatior adults laid 84 to 97% of their egg masses onS. viarum, and 3 to 16% on S. melongena. Non-choice host-specificity tests were also conducted in quarantine in which M. elatior adults and neonate larvae were exposed to 17 and 19 plant species, respectively. Tests with the neonates indicate that this insect was able to complete its development on S. viarum, S. torvum, S. melongena, and S. capsicoides. Although some adult feeding and oviposition occurred on S.melongena in quarantine on potted plants in small cages, no feeding or oviposition by M. elatiorwas observed in field experiments conducted in Brazil. Surveys in unsprayed S. melongena fields in Argentina and Brazil indicated that M. elatioris not a pest of S. melongena in South America. The evidence obtained from the South-American field surveys, Brazil open-field experiments, and Florida quarantine host specificity tests indicate that M. elatior causes significant feeding damage toS. viarum, and does not represent a threat to S. melongena crops in the USA. Therefore an application for permission to releaseM. elatior against S. viarum in the USA was submitted in October 1998. This revised version was published online in July 2006 with corrections to the Cover Date.