Neonicotinoid resistance in the German cockroach (Dictyoptera: Blattellidae)

German cockroaches (Blattella germanica) are one of the most prevalent and pervasive indoor pest species in the world. Infestations can lead to many negative impacts on humans, including sensitization to allergens, increase in asthma symptoms, mental health declines, and potentially, the spread of diseases. While insecticides remain the most effective and affordable option for German cockroach control, resistance to many commonly used insecticide active ingredients (AIs), such as pyrethroids, has been observed at high levels across different populations. Given the high levels of resistance to pyrethroids, inclusion of insecticides with alternative modes of action, such as neonicotinoids, could potentially increase the efficacy of indoor cockroach insecticidal treatments. While previous studies have found low levels of neonicotinoid resistance in German cockroaches despite the common use of neonicotinoid-containing insecticidal products indoors, there is limited information available on the distribution and magnitude of neonicotinoid resistance in German cockroaches. In this study, we investigated German cockroach neonicotinoid resistance patterns in populations collected from homes and businesses throughout the eastern USA, with a focus on the following AIs: dinotefuran, imidacloprid, and thiamethoxam. Furthermore, we evaluated the efficacy of neonicotinoid-based commercial products utilized for German cockroach control in an attempt to link insecticide resistance and product performance. Understanding German cockroach resistance to neonicotinoid AIs will facilitate better cockroach control, thereby improving human health and quality of life.