EVALUATION OF Citrus limon, Lavandula angustifolia AND Mentha piperita FOR THE CONTROL OF GERMAN COCKROACH (Blattella germanica) IN LABORATORY BIOASSA

Abstract

The German cockroach, Blattella germanica Linnaeus (Blattodea: Blattellidae),is one of the most common cosmopolitan and prominent household insect species worldwide. Its control has relied largely on sprays, using conventional insecticidal agents. This has however remained a challenge globally, due to adverse effects and risks associated with such insecticides. Essential oils derived from plants have been traditionally used to protect stored grain and to repel/control flying insects. This study was conducted to evaluate the insecticidal activity of essential oils from Mentha piperita, Citrus limon, and Lavandula angustifolia and baking soda+sugar at varying concentrations against B. germanica under laboratory condition. Data were pooled and statistically analyzed using SPSS v27. Complete mortality (100%) was recorded by M. piperita oil (LC₅₀3.273ml/cm³) at 5 ml/cm³ after 72 hours exposure, 60% by L. angustifolia oil (LC₅₀14.396  ml/cm3) and baking soda+sugar (LC₅₀25.660 ml/cm ) at 10 ml/cm after 96 hours, respectively. The results also showed that M. piperita oil had the highest toxicity against B. germanica with KD values of 37 hours followed by Lavender oil and Baking soda+sugar with KD values of 96 hours each. Summarily, toxicity indicated the order of KD₅₀ and LT₅₀ against B. germanica in treatments as M. piperita oil>L. angustifolia  oil>Baking soda+sugar. These botanical extracts can be considered as viable alternatives and/or complements to conventional synthetic control agents, as well as precursors to new pesticide products.