Comparison of the phytoseiid mites Amblyseius swirskii and Amblydromalus limonicus for biological control of chilli thrips, Scirtothrips dorsalis (Thysanoptera: Thripidae).

Authors: SCHOELLER, E - University Of Florida; McKenzie, Cindy; OSBORNE, L - University Of Florida

Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2020
Publication Date: 10/6/2020
Citation: Schoeller, E.N., McKenzie, C.L., Osborne, L.S. 2020. Comparison of the phytoseiid mites Amblyseius swirskii and Amblydromalus limonicus for biological control of chilli thrips, Scirtothrips dorsalis (Thysanoptera: Thripidae). Experimental and Applied Acarology. 82:309-318. https://doi.org/10.1007/s10493-020-00556-5.
DOI: https://doi.org/10.1007/s10493-020-00556-5

Interpretive Summary: The chilli thrips Scirtothrips dorsalis Hood is a recently established pest in the United States and poses a serious risk to many economically important ornamental and food crops. In this study the biological control potential of the phytoseiid mites Amblydromalus limonicus (Garman and McGregor) and Amblyseius swirskii (Athias-Henriot) were compared by examining their predation and oviposition rates when fed different developmental stages of Scirtothrips dorsalis under laboratory conditions. Mites were equally effective in predation and oviposition rates when fed chilli thrips and both preferred the larval stage. While the results showed that the biological control potential of both mite species were similar, having an additional predator available that may be as effective as Amblyseius swirskii, a proven control agent against Scirtothrips dorsalis in the field, warrants additional research into its potential utility in management of this invasive pest.

Technical Abstract: The chilli thrips Scirtothrips dorsalis Hood is a recently established pest in the United States and poses a serious risk to many economically important ornamental and food crops. In this study the biological control potential of the phytoseiid mites Amblydromalus limonicus (Garman and McGregor) and Amblyseius swirskii (Athias-Henriot) were compared by examining their predation and oviposition rates when fed different developmental stages of Scirtothrips dorsalis. Gravid females were offered 10 individuals of either first instar, second instar, or adult S. dorsalis using a no-choice leaf disc bioassay and predation and oviposition rates were assessed daily for three days. There was no significant difference in predation and oviposition rates between mite species fed specific Scirtothrips dorsalis life stages. There was, however, a significant effect of Scirtothrips dorsalis life stage on the oviposition and predation rates observed for each mite species. The larval stage was the most preferred stage for both mite species, with Amblyseius swirskii consuming 4.6–6.3 and Amblydromalus limonicus 4.8–6.4 individuals/day compared to only 1.6–1.7 adults/day consumed. Female A mblyseius swirskii and Amblydromalus limonicus laid 0.55–0.75 and 0.725 eggs/day on the two larval stages respectively, compared to only 0.25–0.30 eggs/day observed for individuals feeding on adults. While the results showed that the biological control potential of both mite species were similar, having an additional predator available that may be as effective as Amblyseius swirskii, a proven control agent against Scirtothrips dorsalis in the field, warrants additional research into its potential utility.