Study On Improving The Control Effect Of Cynanchum Komarovii Extract On Poratrioza Sinica

Lycium barbarum is an important plant resource and medicinal resource in northwest China.It has many values such as economy,medicine and health care,ecological appreciation and livestock breeding.Ningxia region is the main production area of L.barbarum,but also the import and export of L.barbarum important base.Poratrioza sinica as stinging insects,serious harm in L.barbarum plants,mainly harm in L.barbarum leaves,especially on the back of the leaves,light causes seedlings and leaves wilt,heavy causes the whole L.barbarum plants withered,seriously affecting the development of the Ningxia L.barbarum industry.At present,the chemical control of P.sinica is mainly,but the problem of excessive chemical pesticide residues is often detected in the dried fruit and wet fruit of L.barbarum.The production and export of L.barbarum urgently need to find plant pesticides that can replace the common chemical pesticides.As a rich plant resource in Ningxia region,the extract of Cynanchum komarovii has certain control effect on P.sinica.The study found that plant essential oil extracted from plants has good insecticidal effect to increase the efficacy of C.komarovii.Considering that the wetting and spreading efficiency of the water extract of C.chinensis in the leaves and the body wall of C.chinensis is low,the control effect needs to be improved.In this study,indoor bioassay was carried out to confirm the toxicity of water and plant essential oil extracts of C.komarovii to P.sinica respectively.Plant essential oil with synergistic effect on C.komarovii was selected as synergistic agent,and the effective essential oil was mixed with C.komarovii extract in different proportions to measure the combined toxicity.The essential oil was prepared into microcapsules to improve the characteristics of rapid volatilization of essential oil and exert the insecticidal effect.Additives were added into the extract solution of C.komarovii,and suitable concentrations and types of additives were selected to improve the wetting and deposition of C.komarovii on L.barbarum by measuring the surface tension,contact angle,adhesion tension and other indicators.Finally,the greenhouse pot experiment was carried out to verify the control effect of the combination of essential oil microcapsules and solution of the extract of C.komarovii,providing reference for field application.The main research results are as follows:The extract is soluble in water,and its water agent has certain contact activity against P.sinica.When the concentration of the extract was lower than 100 mg/L,the corrected mortality rate of P.sinica was lower than 55.1% in 48 h.The mortality rate of P.sinica was lower,and the control effect should be improved.Eugenol,citronellal,eucalyptol and limonene were effective against P.sinica,and eucalyptol had the best effect.At 6 h,the mortality rate of eucalyptol to psyllid could reach 55%.It was found that the combined toxicity of eucalyptol extract and eucalyptol extract was greater than 120 with different mass ratios,showing the synergistic effect.Infrared analysis,particle size and release rate measurement of the prepared eucalyptus microcapsules proved that eucalyptus essence was successfully encapsulated in the capsule,and the release rate of eucalyptus microcapsules was slower than that of conventional emulsion.By scanning electron microscopy and contact angle measurement,the results showed that the fruits were hydrophilic and the leaves were hydrophobic.It was found that the surface free energy of L.barbarum fruit was higher than that of leaf,which further verified the hydrophilicity of L.barbarum fruit and leaf.By measuring the surface tension,adhesion tension,adhesion work and other indicators,it was found that adding additives improved the wettability of the liquid medicine,realized the hydrophilicity of the leaf hydrophobic interface,and increased the deposition and wetting on the leaf.Additives have no harm and adverse effects on L.barbarum plants,fruits and leaves can develop normally,L.barbarum fruit normal expansion,fruit full,bright color,leaves show a healthy state,additives can regulate the wetting properties of the solution,the liquid retention performance,among which the surfactant additives Silwet 618 for L.barbarum leaf wetability is the best.The mortality rate tended to be stable after 72 h due to the short duration and weak rapid effect.The greenhouse pot experiment was conducted by combining the extract of C.komarovii with Silwet 618 additives and eucalyptus microcapsules.It was found that the combination of C.komarovii extract and eucalyptus extract with additives improved the control effect of P.sinica.Compared with the single dose of C.komarovii,the control effect of the combined agents on psyllid was increased by about 50%,and the duration was increased,and the pest reduction rate was still up to 72% 7 days after the treatment.