Silencing gut genes associated with the peritrophic matrix of Reticulitermes flavipes (Blattodea: Rhinotermitidae) increases susceptibility to termiticides

The peritrophic matrix (PM) is a noncellular structure that lines the gut of most insects. Because of its close involvement in digestive processes and its role as a barrier against pathogens and toxins, the PM is an attractive target for pest management strategies. The objectives of this study were to (1) reduce the expression of a chitin synthase gene ( Reticulitermes flavipes chitin synthase B , RfCHSB ), a putative peritrophin [ R. flavipes Protein with Peritrophin‐A domain 1, ( RfPPAD1 )] and a confirmed peritrophin [ R. flavipes Protein with Peritrophin‐A domain 2 ( RfPPAD2 )] in R. flavipes by means of RNA interference, and (2) to evaluate the susceptibility of R. flavipes to termiticides and a bacterial pathogen, after silencing the target genes. Force feeding termites with 55 and 100 ng of long double‐stranded RNAs (dsRNAs), targeting RfCHSB and RfPPAD2 , respectively, resulted in the highest levels of transcript suppression. RfCHSB expression was reduced by 70%, whereas the transcript level of RfPPAD2 was decreased by 90%. Force feeding 100 ng/termite of a long RfPPAD1 dsRNA reduced the expression of the transcript by 30%. Challenging termites with imidacloprid, chlorantraniliprole and noviflumuron, after silencing RfCHSB , significantly increased termite mortality. Force feeding termites a dsRNA cocktail, targeting RfCHSB , RfPPAD1 and RfPPAD2 , caused the highest significant increase in termite mortality after challenging the insects with imidacloprid. These results demonstrate the viability of the R. flavipes PM as a target in termite pest management.