THE EFFICACY OF LEMONGRASS (CYMBOPOGON CITRATUS) AND PEPPERMINT ( MENTHA �PIPERITA ) OIL AS A NATURAL GERMAN COCKROACH KILLER

Abstract

Cockroaches pose significant health risks in the Philippines due to their ability to survive extreme environmental conditions and their resistance to various control measures. The German cockroach, in particular, is highly dependent on human habitation and is commonly found in households. While commercial chemical cockroach repellents are widely used, they may cause respiratory problems and damage to the central nervous system, especially in vulnerable populations such as developing fetuses. Because of these concerns, this study aimed to develop a natural cockroach killer spray using lemongrass (Cymbopogon citratus) extract and peppermint (Mentha × piperita) oil as a safer alternative to chemical pesticides for both human health and environmental protection. An experimental research design was employed in Barangay Apo Esquivel, San Antonio, Nueva Ecija, Philippines. The study focused on the use of lemongrass and peppermint oil as natural cockroach killers. Lemongrass was washed, cut, and boiled in hot water for 30 minutes to obtain the extract. Three different spray formulations were prepared, namely 50% water, 25% lemongrass extract, and 25% peppermint oil; 50% water, 37.5% lemongrass extract, and 12.5% peppermint oil; and 50% water, 12.5% lemongrass extract, and 37.5% peppermint oil. These formulations were tested to determine their effectiveness against German cockroaches. The results showed that the combined use of lemongrass extract and peppermint oil was effective in killing cockroaches naturally and consistently. The concentration of lemongrass significantly influenced the effectiveness of the spray, as mixtures with higher lemongrass content killed cockroaches faster. The addition of peppermint oil enhanced both the aroma and overall efficacy of the spray. Although commercially available cockroach killers acted more rapidly, the natural spray made from lemongrass and peppermint oil was found to be safer and more environmentally friendly. The findings demonstrated that the combination of lemongrass and peppermint oil is effective in eliminating German cockroaches. Among the tested formulations, the mixture containing 50% water, 37.5% lemongrass extract, and 12.5% peppermint oil yielded the most successful results. The study concludes that sprays with higher lemongrass content have a greater potential for cockroach control, supporting the use of plant-based alternatives as safer and eco-friendly pest management solutions.