ARS | Publication request: The host range and impact of Bikasha collaris (Coleoptera: Chrysomelidae), a promising candidate agent for biological control of Chinese tallow, Triadica sebifera (Euphorbiaceae) in the United States

Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 23, 2010
Publication Date: December 1, 2010
Citation: Huang, W., Wheeler, G.S., Purcell, M., Ding, J. 2010. The host range and impact of Bikasha collaris (Coleoptera: Chrysomelidae), a promising candidate agent for biological control of Chinese tallow, Triadica sebifera (Euphorbiaceae) in the United States. Biological Control. 56(3):230-238.

Interpretive Summary: Native to China, the Chinese tallow (Triadica sebifera), is an aggressive woody weed in the southeastern United States. The flea beetle, Bikasha collaris, is a common insect attacking this plant in China. To evaluate its potential as a biological control agent of Chinese tallow, biology, safety and impact of this beetle was studied in China. In the laboratory, adults ate leaves producing irregular pits and eggs are laid in folds of filter paper within 6 days after mating. Eggs hatched in the dark and took 6-17 days to incubate. Larvae fed on roots producing elongate tunnels and took 13-23 days to reach the pupal stage. Pupae took 6-14 days to complete development. The potential host range of this flea beetle was evaluated on 68 plant species in 21 families through no-choice and choice tests. Adults only survived and fed on plants from the Chinese tallow genus (Triadica) while larvae only developed successfully on this same species in no-choice tests. Under choice conditions, adults showed a distinct preference for Chinese tallow over other related (congener) species. The impact of the above and belowground herbivory in different insect density on the growth of Chinese tallow was evaluated in a common garden. The flea beetle reduced total biomass, stem height, stem diameter and number of leaves at high density. However, no significant difference was found between adults and larvae herbivory treatments. The results of this study suggested that the flea beetle is a potential biological control agent of the weed Chinese tallow though further tests on native North American species are needed.

Technical Abstract: Native to China, the Chinese tallow, Triadica sebifera (Euphorbiaceae) is an aggressive woody invader in the southeastern United States. The flea beetle, Bikasha collaris (Coleoptera: Chrysomelidae), is a common herbivore attacking this plant in China. To evaluate its potential as a biological control agent of T. sebifera, biology, host specificity and impact of this beetle was studied in China. In the laboratory, adults fed on leaves producing irregular pits and oviposited in folds of filter paper within 6 days after mating. Eggs hatched in the dark and took 6-17 days to incubate. Larvae fed on roots producing elongate tunnels and took 13-23 days to reach the pupal stage. Pupae took 6-14 days to complete development. The potential host range of B. collaris was evaluated on 68 plant species in 21 families through no-choice and choice tests. Adults only survived and fed on plants from the genus Triadica while larvae only developed successfully on T. sebifera in no-choice tests. Under choice conditions, adults showed a distinct preference for T. sebifera over other Triadica species. The impact of the above and belowground herbivory in different insect density on the growth of T. sebifera was evaluated in a common garden. B. collaris could reduce total biomass, stem height, stem diameter and number of leaves at high density. However, no significant difference was found between adults and larvae herbivory treatments. The results of this study suggested that B. collaris is a potential biological control agent of T. sebifera though further tests on native North American species are needed.