Repellency of Oregano (Lippia Graveolens HBK) Against Periplaneta americana (Blattodea: Blattidae) From Durango, Mexico in Vitro

2. Universidad Nacional Autónoma de México, Instituto de Química, , Mexico

Abstract: Sewer cockroaches have become an important pest in the health sector due to the microorganisms that it carries over its body. They contaminate food and mainly affect the respiratory tract. Most of the chemical insecticides used to control this pest, affect people’s health and the cockroaches have become more resistant. The use of aromatic plants is a friendly alternative to the environment in pest control. In this investigation, the repellent effect of residual extracts (hydrolates) of oregano from three municipalities of Durango were evaluated. Control cockroaches were given water and those in the test groups, oregano hydrosols. The survival of the insects was evaluated daily for four weeks. Survival data obtained were successful for the hydrosols from the municipalities of Mezquital and Nombre de Dios with similar chemical composition. In addition to the repellent effect of the hydrosols, an insecticidal effect was also manifested. The analysis of variance of the bioassays showed significant differences for a confidence interval of 95%. The results of Kaplan-Miers survival analysis, showed oregano hydrosols with higher thymol contents, were more effective. Oregano hydrosols (Lippia graveolens) containing mainly thymol, are effective in controlling Periplaneta americana and could reduce insecticide contamination.