Water Emulsion Preparation And Insecticidal Study Of Elsholtzia Ciliate Essential Oil And Its Main Composition Carvone

Chinese grain storage ranks first in the world.In the process of grain storage,pest infestation is the primary problem.When pests infest stored food,it reduces its value and causes significant economic losses.Traditional chemically synthesized insecticides,when used excessively,not only increase the pests’resistance but also pollute the environment.Hence,it is necessary to find green and environmentally friendly plant source insecticides.China has an abundance of Elsholtzia,a genus of plants with extensive pharmacological and biological effects.Previous research has focused on preventing and controlling storage pests.This study selected E.ciliate and carvone,the main component of the essential oil of E.ciliate,to explore the effects on T.castaneum.The study examined different biological activities such as fumigation,contact toxicities,repellency,antifeedant,and population suppression on different developmental stages of T.castaneum.Based on these results,the study selected the natural insecticide diatomite combined with essential oil and carvone for T.castaneum control.Finally,the essential oil of E.ciliate and carvone were prepared as water emulsions and tested in a simulated warehouse to evaluate their post-formulation activity,the main results of the research are as follows:1.Through the determination of the contact toxicities,fumigation,repellency,antifeedant,and population inhibitory activities of the essential oil of E.ciliate and carvone on different developmental stages（egg,larvae,pupae,and adults）of T.castaneum,it was found that:eggs,larvae,pupae,and adults of T.castaneum all have a certain inhibitory effect.In terms of fumigation activity,carvone(LC₅₀=5.02 mg/L)has a stronger fumigation effect on elderly adults than essential oil from E.ciliate(LC₅₀=8.72mg/L).For contact killing activity,carvone(LD₅₀=4.33μg/adult)on elderly adults is stronger than that of essential oil of E.ciliate(LD₅₀=7.62μg/adult).Meanwhile,with the prolongation of treatment time,the repellent effect of the essential oil of E.ciliate and carvone on the larvae and adults of T.castaneum gradually weakened.For example,when78.63 n L/cm² of E.ciliate essential oil was used to treat the elderly adults of T.castaneum,the repellent rate was greater than 80%after 2 hours of treatment,and less than 50%after120 hours of treatment.2.The study found that 100%mortality of T.castaneum was achieved when treated with 1500 ppm of diatomaceous earth using the mixed grain method for 15 days.Additionally,the inhibitory effect on T.castaneum was improved when combining diatomaceous earth with the essential oil of E.ciliate and carvone.For instance,treatment with 3000 ppm of E.ciliate essential oil using the mixed grain method for 15 days resulted in 80%mortality of T.castaneum.After combining E.ciliate essential oil with diatomaceous earth,the mortality rate increased significantly to 93%after 15 days of treatment on red clover.3.The formula for carvone water emulsion was established through single-factor experiments and response surface optimization.The emulsion contains 5%carvone,an emulsifier with an HLB value of 11,and an emulsifier addition ratio of 5%.The essential oil of E.ciliate was mixed with Cremophor EL,absolute ethanol,and distilled water in a ratio of 7.78:1.58:19.26:6.15:65.23.A simulation experiment was conducted in a chamber,which showed a high lethality rate of T.castaneum when treated with the essential oil of E.ciliate and the water emulsion of carvone for 30 days.The highest dose treatment group achieved a 99%lethality rate,and there was almost no insect infestation.Overall,the activity test results of the essential oil of E.ciliate and the water emulsion of carvone against T.castaneum were relatively satisfactory in the simulated warehouse experiment.The project is based on the traditional approach of"preventing storage pests"and aims to develop an assessment method for ecological control of storage pests using plant resources.The research focuses on the insecticidal properties of E.ciliate and its main component,carvone,by examining their effects on different developmental stages of T.castaneum.Then preparations of E.ciliate essential oil and carvone were made.The study also investigates the formulation effects through simulated warehouse experiments.The study using interdisciplinary approaches such as phytochemistry,pharmacy,and insect toxicology.By integrating various disciplines,this research provides a reference for the industrial production and comprehensive utilization of Elsholtzia and carvone.