The ingestion of double-strand RNAs (dsRNA) targeting essential genes in an insect could cause mortality. Based on this principle, a new generation of insect control methods using RNA interference (RNAi) are being developed. In this work, we developed a bioassay for oral delivery of dsRNA to an invasive forest and urban tree pest, the emerald ash borer (EAB, Agrilus planipennis). EAB feeds and develops beneath the bark, killing trees rapidly. This behavior, coupled with the lack of a reliable artificial diet for rearing larvae and adults, make them difficult to study. We found that dsRNA is transported and processed to siRNAs by EAB larvae within 72 h after ingestion. Also, feeding neonate larvae with IAP (inhibitor of apoptosis) or COP (COPI coatomer, β subunit) dsRNA silenced their target genes and caused mortality. Both an increase in the concentration of dsRNA fed and sequential feeding of two different dsRNAs increased mortality. Here we provide evidence for successful RNAi in EAB, and demonstrate the development of a rapid and effective bioassay for oral delivery of dsRNA to screen additional genes.
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This work was supported by the USDA Forest Service Forest Health Center, and by the National Institute of Food and Agriculture, USDA, HATCH under 2351177000.
This is publication number 17–08–072 from the Kentucky Agricultural Experimental Station and is published with the approval of the director.
Rodrigues, Thais B.; Rieske, Lynne K.; Duan, Jian J.; Mogilicherla, Kanakachari; and Palli, Subba Reddy, "Development of RNAi Method for Screening Candidate Genes to Control Emerald Ash Borer, Agrilus planipennis" (2017). Entomology Faculty Publications. 141.