An Environmentally-Friendly RNAi Yeast-Attractive Targeted Sugar Bait Turns off the Drosophila suzukii Rbfox1 Gene

Spotted wing drosophila (SWD), <i>Drosophila suzukii</i> (Diptera: Drosophilidae), are invasive vinegar flies of East Asian origin that are an increasingly global threat to the small fruit industry. It is essential that new classes of eco-friendly insecticides and cost-effective strategies for SWD control are developed. Here, we describe the preparation of a strain of RNA interference (RNAi) <i>Saccharomyces cerevisiae</i> expressing shRNA that specifically targets the SWD <i>RNA-binding Fox protein 1 (Rbfox1)</i> gene. The yeast effectively silences the SWD <i>Rbfox1</i> gene, resulting in significant loss of fly neural activity. Laboratory trials demonstrated that the RNAi yeast can be mixed with soda, which functions as SWD attractive targeted sugar bait (ATSB) that can be delivered in a soda bottle feeder. The ATSB, mixed with yeast that was heat-killed prior to suspension in the ATSB, resulted in 92 ± 1% mortality of SWD flies that consumed it, yet had no impact on non-target dipterans. Rbfox.687 yeast delivered in ATSB feeders may one day be a useful component of integrated SWD control programs.