@article{gonzalez-morales_devries_sierras_santangelo_kakumanu_schal_2021, title={Resistance to Fipronil in the Common Bed Bug (Hemiptera: Cimicidae)}, volume={58}, ISSN={["1938-2928"]}, url={https://doi.org/10.1093/jme/tjab040}, DOI={10.1093/jme/tjab040}, abstractNote={AbstractCimex lectularius L. populations have been documented worldwide to be resistant to pyrethroids and neonicotinoids, insecticides that have been widely used to control bed bugs. There is an urgent need to discover new active ingredients with different modes of action to control bed bug populations. Fipronil, a phenylpyrazole that targets the GABA receptor, has been shown to be highly effective on bed bugs. However, because fipronil shares the same target site with dieldrin, we investigated the potential of fipronil resistance in bed bugs. Resistance ratios in eight North American populations and one European population ranged from 1.4- to >985-fold, with highly resistant populations on both continents. We evaluated metabolic resistance mechanisms mediated by cytochrome P450s, esterases, carboxylesterases, and glutathione S-transferases using synergists and a combination of synergists. All four detoxification enzyme classes play significant but variable roles in bed bug resistance to fipronil. Suppression of P450s and esterases with synergists eliminated resistance to fipronil in highly resistant bed bugs. Target-site insensitivity was evaluated by sequencing a fragment of the Rdl gene to detect the A302S mutation, known to confer resistance to dieldrin and fipronil in other species. All nine populations were homozygous for the wild-type genotype (susceptible phenotype). Highly resistant populations were also highly resistant to deltamethrin, suggesting that metabolic enzymes that are responsible for pyrethroid detoxification might also metabolize fipronil. It is imperative to understand the origins of fipronil resistance in the development or adoption of new active ingredients and implementation of integrated pest management programs.}, number={4}, journal={JOURNAL OF MEDICAL ENTOMOLOGY}, publisher={Oxford University Press (OUP)}, author={Gonzalez-Morales, Maria A. and DeVries, Zachary and Sierras, Angela and Santangelo, Richard G. and Kakumanu, Madhavi L. and Schal, Coby}, editor={Hribar, LawrenceEditor}, year={2021}, month={Jul}, pages={1798–1807} }
 @article{sierras_wada-katsumata_schal_2018, title={Effectiveness of Boric Acid by Ingestion, But Not by Contact, Against the Common Bed Bug (Hemiptera: Cimicidae)}, volume={111}, ISSN={0022-0493 1938-291X}, url={http://dx.doi.org/10.1093/jee/toy260}, DOI={10.1093/jee/toy260}, abstractNote={AbstractBoric acid has been used as an insecticide in the successful control of agricultural, public health and urban pests long before the advent of synthetic organic pesticides. Boric acid products, formulated as dusts, sprays, granular baits, pastes, gels, and liquids, are widely available to consumers and pest management professionals, especially to control pest infestations within homes. Boric acid dust is commonly used against bed bugs (Cimex lectularius L. [Hemiptera: Cimicidae]), but its efficacy has not been demonstrated. We evaluated the efficacy of boric acid as an ingestible and residual contact insecticide on bed bugs, and compared its efficacy on the German cockroach (Blattella germanica L. [Blattodea: Ectobiidae]) which is known to be susceptible to boric acid by both routes. Dose–response studies of 0–5% boric acid in blood demonstrated that ingested boric acid caused rapid mortality at concentrations of ≥2%, and even 0.5% and 1% boric acid caused 100% mortality, albeit at a slower time course. In contrast, bed bugs survived contact with high concentrations of boric acid dust. Smaller boric acid particles did not increase mortality of either unfed or recently fed bed bugs. The same boric acid products were effective at causing mortality of German cockroaches by both contact and ingestion. We thus conclude that although boric acid is an excellent candidate active ingredient for an ingestible bait formulation, residual applications of dust or spray would be ineffective in bed bug interventions.}, number={6}, journal={Journal of Economic Entomology}, publisher={Oxford University Press (OUP)}, author={Sierras, Angela and Wada-Katsumata, Ayako and Schal, Coby}, year={2018}, month={Sep}, pages={2772–2781} }
 @article{sierras_schal_2016, title={Comparison of ingestion and topical application of insecticides against the common bed bug, Cimex lectularius (Hemiptera: Cimicidae)}, volume={73}, ISSN={1526-498X}, url={http://dx.doi.org/10.1002/ps.4464}, DOI={10.1002/ps.4464}, abstractNote={AbstractBACKGROUNDThe global prevalence of Cimex lectularius infestations has challenged current intervention efforts, as pyrethroid resistance has become ubiquitous, availability of labeled insecticides for bed bugs is limited, and non‐chemical treatment options, such as heat, are often unaffordable. We evaluated representative insecticides toward the goal of developing a novel, ingestible liquid bait for hematophagous arthropods.RESULTSLC50 values were estimated for adult males and first instar nymphs of an insecticide‐susceptible strain for abamectin, clothianidin, fipronil and indoxacarb, after ingestion from an artificial feeder. LD50 values were calculated based on the ingested blood volume. Ingested abamectin, clothianidin and fipronil caused rapid mortality in both life stages. Fipronil was ∼43‐fold more effective by ingestion than by topical application. Indoxacarb and its bioactive metabolite decarbomethoxylated JW062 (DCJW) were ineffective at causing bed bug mortality even at concentrations as high as 1000 ng mL−1 blood.CONCLUSIONSFipronil, clothianidin and abamectin have potential for being incorporated into a liquid bait for bed bug control; indoxacarb and DCJW were not effective. Bed bugs are a good candidate for an ingestible liquid bait because systemic formulations generally require less active ingredient than residual sprays, they remain contained and more effectively target hematophagous arthropods. © 2016 Society of Chemical Industry}, number={3}, journal={Pest Management Science}, publisher={Wiley}, author={Sierras, Angela and Schal, Coby}, year={2016}, month={Dec}, pages={521–527} }