Bio-active essential oils derived from medicinal plants and their insecticidal potential on houseflies and cockroaches

Abstract

The plant essential oils are intricate blends of semi-volatile and volatile substances. They primarily consist of monoterpenes and sesquiterpenes; however, very trace amounts of diterpenes, triterpenes, and tetraterpenes are also present. In view of environmental concerns, highly aromatic essential oils, exhibit a variety of bioactivities against the targeted species as a novel pest control alternative to synthetic insecticides. As a result, the study aims to evaluate the impact of essential oils (EO) extracted from various plant species: Azadirachta indica, Citrus limon, Eucalyptus globulus, Laurus nobilis, Mentha piperita, and Ocimum tenuiflorum. Gas chromatography and Mass spectrometry (GC–MS) were used to determine the chemical components of these essential oils. Furthermore, the extracted oils were subjected to individual and combination formulations of bio-insecticides, which were assessed on houseflies and cockroaches in comparison to a blank control and the positive control dichlorvos (dimethyl 2, 2-dichlorovinyl phosphate). The findings showed that the maximum essential oil yields from the leaves of A. indica, E. globulus, and O. tenuiflorum were 11.38, 9.64 and 10.41 %, respectively. Compared to DDVP, which killed all insects within the 12-hour period, the combined form of leaf essential oils at 100 % concentration proved to be more effective in controlling insect mortality. It accounted for 98 % of the deaths in houseflies and 76.4 % of the deaths in cockroaches, according to the contact toxicity evaluation. The active insecticidal components in the formulation include eucalyptol, undecane, tetradecane, estragole, pentadecane, and caryophyllene.