# Effects of Orally Delivered Double-Stranded RNA of Trehalose-6-Phosphate Synthase on the Population of Frankliniella occidentalis

## TL;DR

This study shows that RNA interference targeting the TPS gene in western flower thrips can significantly reduce their survival and reproduction, offering a sustainable pest control method.

## Contribution

The study demonstrates that orally delivered dsRNA targeting FoTPS effectively suppresses western flower thrips populations.

## Key findings

- Feeding dsFoTPS increased mortality of western flower thrips nymphs and adults and reduced adult egg production.
- Bacterial delivery of dsFoTPS extended pre-reproductive periods and reduced survival, fecundity, and population growth.
- Population simulations showed dsFoTPS delivery reduced WFT populations to 1/34 of controls within 100 days.

## Abstract

Western flower thrips (WFTs, Frankliniella occidentalis) are damaging invasive pests in agriculture. Traditional chemical controls have led to resistance and environmental concerns, driving the search for eco-friendly alternatives. RNA interference (RNAi) targeting the trehalose-6-phosphate synthase (TPS) gene shows potential for pest management. Feeding dsRNA targeting FoTPS significantly increased the mortality of WFT nymphs and adults and reduced the egg production of adults. Using bacteria to deliver dsFoTPS further extended the pre-reproductive period and decreased survival, fecundity, and population growth. This study demonstrates that RNAi targeting FoTPS can effectively suppress WFT populations, offering a sustainable pest control strategy.

The invasive pest Frankliniella occidentalis (western flower thrip, WFT) severely impacts agricultural production. RNA interference (RNAi) has emerged as a viable alternative to chemical control methods. Trehalose-6-phosphate synthase (TPS) is an important enzyme for the synthesis of trehalose in insects. The TPS gene is a potential target for RNAi-based pest control; however, its efficacy against WFTs remains unclear. Feeding with the synthesized dsFoTPS to WFT significantly increased the mortalities of first- and second-instar nymphs and adults and significantly decreased the number of eggs laid by adults within 72 h; the expression of FoTPS was significantly down-regulated in 24, 48, and 72 h. Ingestion of WFTs on Escherichia coli expressing dsFoTPS led to a marked increase in the total pre-reproductive period; reductions in survival rate, adult longevity, oviposition days, fecundity, peak reproduction value, the intrinsic rate of increase, the finite rate of increase, and the net reproductive rate; and an extension of the mean generation time. TPS gene expression was significantly down-regulated on days 7 and 28. A population simulation of WFTs fed with E. coli expressing dsFoTPS indicated that the population suppression was reduced to 1/34 of the control in 100 d. Oral delivery of E. coli expressing dsFoTPS effectively inhibited the survival, fecundity, and population growth of WFTs, offering a novel approach and rationale for the prevention and control of WFTs.