Demonstration of RNAi Yeast Insecticide Activity in Semi-Field Larvicide and Attractive Targeted Sugar Bait Trials Conducted on <i>Aedes</i> and <i>Culex</i> Mosquitoes
Akilah T. M. Stewart,
Keshava Mysore,
Teresia M. Njoroge,
Nikhella Winter,
Rachel Shui Feng,
Satish Singh,
Lester D. James,
Preeraya Singkhaimuk,
Longhua Sun,
Azad Mohammed,
James D. Oxley,
Craig Duckham,
Alongkot Ponlawat,
David W. Severson,
Molly Duman-Scheel
Affiliations
Akilah T. M. Stewart
Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, USA
Keshava Mysore
Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, USA
Teresia M. Njoroge
Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, USA
Nikhella Winter
Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
Rachel Shui Feng
Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
Satish Singh
Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
Lester D. James
Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
Preeraya Singkhaimuk
Department of Entomology, US Army Medical Directorate–Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok 10400, Thailand
Longhua Sun
Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, USA
Azad Mohammed
Department of Life Sciences, Faculty of Science & Technology, The University of the West Indies, St. Augustine Campus, St. Augustine, Trinidad and Tobago
James D. Oxley
Southwest Research Institute, San Antonio, TX 78238, USA
Craig Duckham
CD R&D Consultancy Services, Dorking RH4 2HF, UK
Alongkot Ponlawat
Department of Entomology, US Army Medical Directorate–Armed Forces Research Institute of Medical Sciences (USAMD-AFRIMS), Bangkok 10400, Thailand
David W. Severson
Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, USA
Molly Duman-Scheel
Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, USA
Eco-friendly new mosquito control innovations are critical for the ongoing success of global mosquito control programs. In this study, Sh.463_56.10R, a robust RNA interference (RNAi) yeast insecticide strain that is suitable for scaled fermentation, was evaluated under semi-field conditions. Inactivated and dried Sh.463_56.10R yeast induced significant mortality of field strain Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus larvae in semi-field larvicide trials conducted outdoors in St. Augustine, Trinidad, where 100% of the larvae were dead within 24 h. The yeast was also stably suspended in commercial bait and deployed as an active ingredient in miniature attractive targeted sugar bait (ATSB) station sachets. The yeast ATSB induced high levels of Aedes and Culex mosquito morbidity in semi-field trials conducted in Trinidad, West Indies, as well as in Bangkok, Thailand, in which the consumption of the yeast resulted in adult female mosquito death within 48 h, faster than what was observed in laboratory trials. These findings support the pursuit of large-scale field trials to further evaluate the Sh.463_56.10R insecticide, a member of a promising new class of species-specific RNAi insecticides that could help combat insecticide resistance and support effective mosquito control programs worldwide.
