| In this thesis we carried on the preliminary study to the extraction process of plant essential oil, and measured the biological activity of plant essential oil on red flour beetle, Tribolium castaneum and the housefly, Musca domestica vicina. At the same time, the inhibition effect of plant essential oil to pathogenic fungi was determined. The main results are as follows:1. The extraction process research to plant essential oil was implemented, adopted Three Factor Four Level orthogonal experiment design. The best extraction process condition is AaBaCa, namely 50g experimental plant leaves added 1000ml water, were steam distilled about 120min. And plant essential oil was extracted with the petroleum ether. The solvent was concentrated under vacuum in a rotary evaporator, and we can get biggest income. In three factor the extraction solvent is the most important factor to increase the yield of plant essential oil, and the next is distil time, but the amount of adding the water has less influence to the yield of plant essential oil.2. Plant essential oil on stored-product pest insect, adult of Tribolium castaneum and sanitary pest insect, adult of Musca domestica vicina has very strong repellant activity. Chi-square analysis indicates that plant essential oil was significantly repellent to Tribolium castaneum adults at the 0.6μl/ml (vol:vol) concentration and above in filter paper arena test. Plant essential oil has particularly significantly repellent effect at the 1.0μl/ml concentration, and the repellent rate achieved 100%, and the repellent grade reached the V class. Bioassay result of plant essential oil on Musca domestica vicina showed that the repellent vigor gained gradually with plant essential oil concentration, applied the "Y" type olfaction instrument. At the dose of 20μl and 25μl, the oil to housefly has very strong repellent activity, and the average repellent activity was 86% and 88% respectively, and showed the remarkably higher than the dose of 5μl and 10μl.3. Topical application was employed for contact toxicity studies of Tribolium castaneum adults and larvae. The results of dose-mortality responsedemonstrated that the tarvae of Tribolium castaneum were more tolerant than the adults to the contact toxicity of the oil. Furthermore, the larvae (10-18 days old) progressively became more susceptible with age, so that the 16- and 18-day larvae were as susceptible as the adults to the oil. The performance progressively augmented for mortality :ate of the insect. In addition, chi-square analysis showed that no significant difference (P>0.05) was observed in the susceptibilities of the various larvae and adults of Tribolium castaneum to the contact toxicity of plant essential oil.4. Plant essential oil has a strong fumigant activity against Tribolium castaneum adults and larvae. Probit analysis of the dose-mortality response of Tribolium castaneum to the oil showed that adults were much mom susceptible than larvae. As the larvae grew older, they became less tolerant. However, there was no significant in various larvae of Tribolium castaneum. At the 4.0 and 8.0μl/ml concentration, the mortality of oil against Tribolium castaneum adults reached 74% and 100% respectively, but at concentration of 8.0μl/ml, 12-day, 14-day and 16-day larvae mortality obtained 49%, 53% and 52% respectively; the sensitivity of various larvae was not significant to fumigant activity of plant essential oil.Plant essential oil to Tribolium castaneum eggs has very strong fumigant activity. With exposure time and concentration of plant essential oil, the fumigant toxicity to Tribolium castaneum eggs progressively increased. Under 10,15 and 20μl/l air and 96h exposure period conditions, the egg's mortality attained 100%; at concentration of 20ul/l air, the mortality of Tribolium castaneum eggs achieved 82% after 24h, 100% after 48h.There was a large influence on developmental inhibition of Tribolium castaneum, which was fumigated by plant essential oil. The experiment results showed that the percentage of...
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