Research And Development Of Plant-Derived Repellent For Dalbergia Odorifera Leaf-Eating Pests

Dalbergia odorifera(Dalbergia odorifera)is a common and precious redwood sp.ecies in my country,cultivated in Hainan,Guangdong,Guangxi and other places.In recent years,one of its leaf-eating pests(Plecoptera bilinealis)has occurred on a large scale,causing significant economic losses to the Dalbergia odorifera industry.At present,the prevention and control of the leaf-eating pest Dalbergia odorifera is mainly chemical control,and the biological control research of plant-derived repellents has not been reported;therefore,this paper takes the leaf-eating pest Dalbergia odorifera as The control object is to select plants with repellent activity from the understory plants in the surrounding area of Dalbergia odorifera plantation as raw materials;mix with the selected pesticide additives to prepare plant-derived repellents,and conduct research on forest control applications.It can provide a scientific basis for preventing the outbreak of the Dalbergia odorifera leaf-eating pest Plecoptera bilinealis.The main findings are as follows:(1)Screening of plants with repellent activity and extraction of effective substancesThrough surveys in the surrounding area of Dalbergia odorifera plantation,three plants containing volatile oils,saponins,and flavonoids,including peppermint,pokeweed and mimosa,were selected.The crude extracts of three plants were extracted by ultrasonic extraction method,and the three plant concentrations were processed at a concentration of 100g/L for different time conditions.The results showed that the repellent effects of peppermint extract at 24h,48h,and 96h were 76.77%,respectively.71.72%,66.67%;the repellent rate of mimosa extract at 24h,48h,and 96h was 67.45%,50.19%,and 42.86%,respectively;the repellent rate of pokeweed extract at 24h,48h,and 96h was each It is 62.40%,54.46%,46.52%,which shows that the crude mint extract has good repellent activity.Then,the crude mint extract was used to determine the repellent rate of the mint extract against the Plecoptera bilinealis at four concentrations of 150 g/L,100 g/L,50 g/L,and 25 g/L.The results of the study showed that:when the concentration was 100 g/L,the repellent effect was the best.The repellent rates of 24h,48h,and 96h were 76.77%,71.72%,and 63.62%respectively;when the concentration was 150 g/L,24h,48h,The repellent rates of 96h were 61.17%,55.42%,47.31%;when the concentration was 50 g/L,the repellent rates of 24h,48h,96h were 58.13%,50.80%,and 43.77%;when the concentration was 25 g/L,The repellent rate of 24h,48h,96h was 39.69%,36.51%,and 31.87%.Therefore,based on the test results,100 g/L peppermint extract was comprehensively selected as the original plant medicine.(2)Development of plant-derived repellentUsing 100g/L peppermint extract as the original plant medicine,the solvent and emulsifier were screened.Solvent optimization results show that the solvent dimethyl sulfoxide and plant extracts have the best solubility,high solubility,brown-yellow mixture,uniform and transparent solution,and no precipitation;emulsifier optimization results show that emulsifier Tween-80 is added Afterwards,the dispersibility and stability of the mixed liquid are all at a qualified level,the performance of cold storage and heat storage is qualified,and the degradation rate is 2.7%,which is less than 5%.Therefore,dimethyl sulfoxide was selected as the solvent of the plant-derived repellent,and Tween-80 was used as the emulsifier.Furthermore,four plant-derived repellents were formulated into four plant-derived repellents in proportions with solvent(dimethyl sulfoxide),emulsifier(Tween-80)and synergist(turpentine),which were named JZQ1(plant raw medicine).:Synergist:Solvent:Emulsifier=24:6:60:10),JZQ2(Plant original medicine:Synergist:Solvent:Emulsifier=48:12:30:10),JZQ3(Plant original medicine:Increase Effective agent:solvent:emulsifier=15:15:60:10),JZQ4(plant original medicine:synergist:solvent:emulsifier=30:30:30:10).(3)Evaluation on the prevention and safety of plant-derived repellents in forestFour repellents,JZQ1,JZQ2,JZQ3,and JZQ4 were used for forest control.The results showed that the insect population reduction rate of JZQ1 repellent 4d after application was 63.88%;the insect population reduction rate of JZQ2 repellent 4d after application It was 51.40%;the insect population reduction rate of JZQ3 repellent 4d after application was 58.34%;the insect population reduction rate of JZQ4 repellent 4d after application was 48.62%.According to the results of forest control,JZQ1 repellent and bio-insect repellent neem oil were used to study the duration of validity.The test results showed that:the insect population reduction rate of JZQ1 agent on the 5th day was 54.18%,and the insect population reduction rate of neem oil was 68.05%on the first day after the application of neem oil.There was a significant difference in the control effect,indicating the duration of the JZQ1 repellent agent For 4d.And because JZQ1 plant-derived repellent contains 24%of crude plant extracts;therefore,JZQ1 repellent is 24%peppermint EC.JZQ1 repellent is used for quality inspection and acute dermal toxicity test in accordance with the national pesticide standard HG/T 2214-2013;the test results show that the dispersibility,water content and other indicators meet the national pesticide standards;at the same time,the pesticides have an effect on mice.The safety test also shows that the medicament does not have a toxic effect on humans and animals.