Bioavailability of chlorantraniliprole and indoxacarb to eastern subterranean termites (Isoptera: Rhinotermitidae) in various soils.

A laboratory study was conducted to determine the toxicity of indoxacarb and chlorantraniliprole to Eastern subterranean termites, Reticulitermes flavipes (Kollar) (Isoptera: Rhinotermitidae) resulting from topical applications and exposure to treated soil. Soils with varying organic matter (0.57-3.64%) and chemical characteristics were used in termiticide bioassays. Lethal dose resulting from topical application indicated that chlorantraniliprole was two- to 11-fold more toxic than indoxacarb. Lethal concentration assays yielded opposite results where concentrations of indoxacarb in soil that caused either 50 or 90% mortality of R. flavipes workers at 48 and 144 h were two- to six-fold lower than chlorantraniliprole. The bioavailability of indoxacarb and chlorantraniliprole was negatively correlated with soil organic matter. Our results suggest that indoxacarb is more bioavailable to termites in soil than chlorantraniliprole based on calculated bioavailability ratios. However, how these laboratory results correlate to actual field application data and termite efficacy is unknown, and more research is needed. These compounds seem to have excellent activity on termites and have potential to provide new modes of action and new chemistry as liquid termiticides.