RNA interference targeting Ras GTPase gene Ran causes larval and adult lethality in Leptinotarsa decemlineata

BACKGROUND RNA interference (RNAi) is a breakthrough technology in pest control. It is highly efficient to Coleopteran pests such as the Colorado potato beetle Leptinotarsa decemlineata, a serious pest defoliator mainly attacking potatoes worldwide. The first step for effective pest control by RNAi is the development of effective and reliable target genes. RESULTS Our results revealed that continuous ingestion of dsLdRan for 3 days successfully silenced the target gene, inhibited larval growth and killed 100% L. decemlineata larvae. When the bioassay began at the second‐, third/fourth‐instar larval stages, the larval lethality mainly occurred at the fourth larval instar and prepupal stages, respectively. Importantly, consumption of dsLdRan for 3 days by the newly‐emerged males and females effectively knocked down the target transcript, reduced fresh weights and caused 100% of lethality within a week. The LdRan females possessed underdeveloped ovaries. CONCLUSION Considering that the larvae, adults and eggs are simultaneously sited on the potato plants, bacterially‐expressed dsLdRan is a potential RNAi‐based strategy for managing L. decemlineata in the potato field. © 2022 Society of Chemical Industry. RNA interference (RNAi) of LdRan in larvae and adults of Leptinotarsa decemlineata caused 100% mortality. Knockdown of LdRan in larvae inhibits growth and development, and silencing LdRan in adults represses feeding and ovary development. Bacterially‐expressed dsLdRan is a potential RNAi‐based strategy for managing L. decemlineata in the potato field.