Insecticidal Activity About The Essential Oil Of Taxodium ’Zhongshanshan’ Against Aphids

The excessive and unscientific use of chemical pesticides seriously threatens the quality of crop products and the safety of agricultural ecological environment in China,so it is of great significance to apply botanical pesticides to the green control of pests.The essential oils of various Taxodiaceae plants have good insecticidal and antibacterial activities,but there are few reports on the insecticidal activity of the essential oils of Taxodium’zhongshanshan’.In this paper,the extraction process of T.’zhongshanshan’ essential oil was optimized,and the contact toxicity of the essential oil and its main components against aphids was determined.A plant essential oil insecticide was developed and the field efficacy trial was carried out.The results of this study enriched the utilization of the resources of T.’zhongshanshan’ and provided the theoretical basis for the development of new botanical insecticides.The main results are as follows:1.Extraction process of T.’zhongshanshan’ essential oilThe essential oil was extracted by Hydrodistillation.The effects of extraction time,extraction temperature and material-liquid ratio on the yield of essential oil were studied.The extraction process of T.’zhongshanshan’ essential oil was determined as follows:extraction temperature is 105℃,extraction time is 8 h，material-liquid ratio is 1:8.2.Chemical composition analysis of T.’zhongshanshan’ essential oilThe results of GC-MS showed that T.’zhongshanshan’ essential oil was composed of 29 volatile components,including terpenes(15 kinds,accounting for 91.01%),alcohols(9 kinds,accounting for 5.38%),alkanes and esters(5 kinds,accounting for 4.61%).Among them,the content of α-pinene was the highest,accounting for 35.38%of all the components,followed by limonene and caryophyllene,with the content of 25.38%and 8.11%respectively.3.Study on insecticidal activity of T.’zhongshanshan’ essential oil and its main components against aphidsThe contact toxicity of T.’zhongshanshan’ essential oil and its main components:α-pinene,limonene and caryophyllene to aphids was determined by micro drop method.The results showed that essential oil,α-pinene,limonene and caryophyllene had well contact toxicity to aphids,and the LC50 of each treatment above at 48 hours were 204.79,357.95,212.73 and 294.65 mg/L.Limonene is considered to be the main insecticidal active component of the essential oil.4.Development of 20%T.’zhongshanshan’ essential oil EW and its performance index testsThrough the selection of surfactants and other additives,the formulation of 20%T.’zhongshanshan’ essential oil EW was determined as follows(calculated by quality):essential oil(20%),surfactant A(10%),surfactant B(10%),antifreeze D(4%),and the rest is made up to 100%with deionized water.The results of the performance index of the preparation showed that the pH value(6.70),pourability,dilution stability,lasting foaming property,freeze-thaw stability,thermal storage stability(digestion rate 2.20%)and low storage stability(digestion rate 1.38%)all met the national quality standards.5.Field efficacy trial of 20%T.’zhongshanshan’ essential oil EWThe results of indoor pot experiment showed that the preparation had good aphid killing activity,and the corrected mortality of aphid reached 78.29%after 48 hours diluted by 100 times.The results of field efficacy trial showed that 20%T.’zhongshanshan’ essential oil EW had a certain control effect on aphids.The control effect was 34.35%and 57.67%at the dosage of 1125 and 2250 mL/hm2 3 days after application.