Biology and Host Specificity of Ageniosa electoralis (Coleoptera: Chrysomelidae), a Prospective Biological Control Agent for Chrysanthemoides monilifera (Asteraceae)

Abstract

Abstract The southern African shrub Chrysanthemoides monilifera (L.) T. Non. (Asteraceae) invades native vegetation and threatens nature conservation objectives throughout its range in Australia. In a survey for biological control agents, adults and larvae of the chrysomelid Ageniosa electoralis (Vogel) were found at two sites in Natal, South Africa, where they fed on the foliage of Chrysanthemoides monilifera rotundata (DC.) T. Norl. In laboratory-based starvation tests, A. electoralis completed larval development or oviposited on 15 nontarget test plant species from the Asteraceae and 1 from the Apiaceae. The number of larvae completing development to adults on Arctotheca calendula (L.) M. Levyns, Cymbonotus preissianus Steetz, and Tussilago farfara L. was similar to that on C. monilifera . Also, the number of eggs laid by adults fed Calendula oflicinalis L. or Daucus carota L. was not significantly different from the number of eggs recorded for adults fed on C. monilifera . In multiple-choice tests that included C. monilifera , larvae fed on six nontarget test plant species. Ageniosa electoralis is not being considered for release as a biological control agent for C. monilifera in Australia until a satisfactory level of host-specificity is shown under field conditions in South Africa.