Origin and Extent of Resistance to Fipronil in the German Cockroach, Blattella germanica (L.) (Dictyoptera: Blattellidae)

Abstract

Fipronil, a phenylpyrazole insecticide, was made available in 1999 in bait formulations for use against the German cockroach, Blattella germanica (L.). We have investigated resistance to fipronil in the descendants of cockroaches collected just before, or contemporaneously with, the introduction of fipronil baits. Cockroaches were obtained in two types of settings: homes that either had or had not been serviced by a pest management professional while occupied by their current residents. Thorough inspections by us turned up no evidence that fipronil had been used in any of the homes, and in addition, no residents claimed to have used baits containing fipronil. Resistance to fipronil was detected by topically dosing adult males with the LC99 of fipronil, the value of which was determined in a dose-response assay with males of an insecticide-susceptible strain. Fewer than 99 of 100 males of all field-collected strains died within 72 h of being treated. Moreover, substantial numbers of males survived doses three and 10-fold greater than the LC99. Regression analysis showed that 67% of the variation in the percentage of males that died after being treated with fipronil was explained by a linear relationship with the percentage that died after being treated with dieldrin. Therefore, it appears that resistance to fipronil in German cockroaches--whose ancestors had never been exposed to it--is attributable to enduring resistance to the cyclodienes, which were formerly used for cockroach control and have a similar mode of action as fipronil. Lastly, we found that insects resistant to topically administered fipronil were likewise resistant, and to a similar degree, to ingested fipronil.

Development of Diagnostic Insecticide Concentrations and Assessment of Insecticide Susceptibility in German Cockroach (Dictyoptera: Blattellidae) Field Strains Collected From Public Housing

“…Our findings are consistent with other studies showing significant indoxacarb (Gondhalekar et al 2013, Ko et al 2016a) and fipronil (Holbrook et al 2003, Chai and Lee 2010, Gondhalekar et al 2011) resistance in German cockroaches. Resistance to indoxacarb and fipronil in the I-IN and D-IL strains are likely the result of prior selection pressure.…”

“…Determining the effects of different insecticide deployment strategies on resistance evolution, such as use of single products versus product rotations or mixtures would provide useful information for developing sustainable resistance management strategies for German cockroaches. Even though susceptibility and resistance of field cockroaches against different AIs was observed in our study, effective control of cockroaches might still be achievable by commercially available chemicals because they are highly palatable and contain extremely high insecticide concentrations (Holbrook et al 2003, Gondhalekar and Scharf 2012, Gondhalekar et al 2013, Ko et al 2016a). However, this possibility does not preclude judicial pesticide use to preserve efficacy of presently available pesticide resources (Gondhalekar and Scharf 2013).…”

“…Historically, German cockroaches have been able to develop extensive resistance to different insecticides (Cochran 1995). Insecticide resistance in laboratory and field-collected German cockroaches has been reported for decades (Bennett and Spink 1968; Koehler and Patterson 1986; Cochran 1987; Umeda et al 1988; Cochran 1989; Hemingway et al 1993a, 1993b; Valles and Yu 1996; Lee et al 1996; Scharf et al 1997; Scharf et al 1998; Wei et al 2001; Holbrook et al 2003; Gondhalekar et al 2011, 2013; Ko et al 2016a; Naqqash et al 2016). In total, German cockroaches have shown resistance to 43 active ingredients (AIs) (Whalon et al 2016), and therefore, resistance management has become a priority in any cockroach IPM program.…”

“…Discriminating dose- or concentration-based approaches have been used successfully for detecting fipronil and indoxacarb resistance in German cockroach field strains (Holbrook et al 2003, Gondhalekar et al 2011, 2013). The research presented here targeted the problem in urban pest management posed by cockroach resistance, using an unprecedented resistance monitoring-based approach that included 14 AIs and a glass vial bioassay method.…”

Insecticide Resistance Profiles and Synergism in Field Populations of the German Cockroach (Dictyoptera: Blattellidae) From Singapore

“…We currently are unable to discern whether the Þpronil resistance in the four strains recorded in this study was due to selection pressure by the Þpronil gel bait, to selection by dieldrin that occurred three decades ago, or both. Holbrook et al (2003) conÞrmed that German cockroach strains that were resistant to cyclodiene were cross-resistant to Þpronil. Kristensen et al (2005) found Þpronil resistance in dieldrin-resistant Danish populations of B. germanica that had never been exposed to Þpronil and demonstrated the involvement of Rdl mutation.…”