ISSN: 01173375 Volume 11, Issue 01, January, 2021 933 The Efficacy of Commercial Aerosol Insecticides to German Cockroaches (Blattella germanica L. ) Populations from Two Places in Indonesia Resti Rahayu 1* , Vivy Hermana Pratiwi 1 , Anggia Safitri 1 , Robby Jannatan 2 Animal Physiology Laboratory, Department of Biology, Universitas Andalas, 25163, Indonesia 1 Animal Structure & Development Laboratory, Department of Biology, Universitas Andalas, 25163, Indonesia 2 Corresponding Author: 1* ABSTRACT— Aerosol spray insecticides are widely available in Indonesia's public market to control the German cockroach population, but the reports on their effectiveness are still limited. This study aimed to determine the efficacy of six pyrethroid insecticides in the form of aerosol sprays (By, Ht, Vp, Nm, Mt, and Fm) against field German Cockroaches populations in Indonesia (Palembang and Bukittinggi populations). Five insecticides effectively paralyzed the Bukittinggi population and ineffective to the Palembang population by the knockdown time (KT90) criteria. All aerosol insecticides were ineffective in killing Bukittinggi and Palembang Cockroaches populations by the lethal time (LT90) criteria. The pyrethroid insecticides sold in the public market were no longer effective in killing the German Cockroaches population. The results show a high level of resistance in two German cockroach populations in Indonesia. KEYWORDS: urban pest, phyrethroid, chemical insecticide, resistance, Indonesia. 1. INTRODUCTION The German cockroach (Blattella germanica L.) is the serious and most important pest in the urban area in many countries of the world [1], [2], [3] and also in Indonesia [4]. The German cockroach is also carrying 27 species of potential bacteria pathogens, such as Klebsiella, Enterobacter, Serratia, and Streptococcus. Almost all of the bacteria are multiple antibiotic resistant’s [5]. Most people in Indonesia control the German cockroach population using chemical insecticides in the form of aerosol sprays. One of the many aerosol sprays sold on the public market is a pyrethroid insecticide. Still, most aerosol spray insecticide has been resistant to some German cockroach populations in Indonesia [6]. There is a specific character of resistance of the cockroach population. The characters can be identified from the different levels and patterns of the Cockroaches population's resistance mechanisms from each place [7]. Synthetic insecticides can quickly kill German cockroaches in some areas, but it may be ineffective in other areas [8]. The present study is monitoring the efficacy of aerosol sprays insecticide in the public market to control the German cockroach population, and this study may offer a new urban pest control management in Indonesia. 2. Material and Method 2.1 Provision of the German cockroach population This study used two field populations of German cockroaches (B. germanica L.) were collected from the field. The populations were the Palembang population (PLZ-PLM) and Bukittinggi population (RMKN- BKT). A standard cockroach that is still susceptible to insecticides was obtained from the Vector Control Research Unit, University Sains Malaysia (VCRU-WHO) (Table 1). All cockroach populations were reared at the Animal Physiology Laboratory of the Biology Department, Andalas University, Indonesia. The