BACKGROUND: Target-selective biopesticides are needed to facilitate integrated pest and pollinator management in urban landscapes and gardens. Bacillus thuringiensis galleriae, strain SDS-502 (Btg), recently registered in the USA and Canada, produces Cry8Da protein active against scarab beetles. We evaluated Btg formulations for managing the Japanese beetle [Popillia japonica Newman (JB)], a polyphagous invasive pest, including residual spray effectiveness for reducing adult feeding on Rosa and Tilia spp., and granular formulations for early- or late-curative control of root-feeding grubs in turfgrass. We also tested for cross-order activity to monarch butterfly (Danaus plexippus L.) larvae and other non-target insects. RESULTS: Field-weathered Btg residues reduced JB feeding on foliage for 3–14 days. Most beetles were still flight-capable after 24 h confinement with Btg-treated leaves. Granular Btg failed to control early- or late-instar JB grubs in soils under several turfgrass species at multiple field sites. In three trials, feeding on Btg-sprayed milkweed resulted in 97–100% mortality of early instar monarchs, with symptoms of B. thuringiensis pathogenesis. Fall armyworms (Spodoptera frugiperda (J.E. Smith)) fed Btg-treated grass had reduced body mass, but there were no adverse effects on lady beetle larvae preying on Btg-sprayed aphids or on the aphids themselves. CONCLUSION: This study supports efficacy of Btg strain SDS-502 for reducing defoliation by adult JB in urban landscape settings. Granular formulations, however, failed to control JB grubs in turfgrass soils. Btg should not be used in gardens with larval host plants of the monarch butterfly or other non-pest Lepidoptera, especially species of conservation concern.
|Number of pages||8|
|Journal||Pest Management Science|
|State||Published - Feb 1 2020|
Bibliographical noteFunding Information:
This paper is dedicated to the memory of Lindsey Wallis (deceased 22 September 2018) who, as an undergraduate intern, made valuable contributions to this research. We thank Adam Baker and Robert Brockman for research assistance, J. White and J. Obrycki for providing us with starter colonies of aphids and H. convergens, respectively, R. Bessin for critically reading the manuscript, and Joe Boggs for providing the graphical abstract photo. This work was supported by the Horticultural Research Institute, University of Kentucky Nursery Research Endowment Fund, USDA-NIFA-SCRI grant 2016-51181-235399 administered through IR4 Grant 2015-34383-23710, and USDA-NIFA Hatch Project no. 2351587000.
© 2019 Society of Chemical Industry
- Bacillus thuringiensis galleriae
- Cry8Da toxin
- cross-order activity
- microbial control
ASJC Scopus subject areas
- Agronomy and Crop Science
- Insect Science