| Maize is one of the three important food crops in China.In recent years,with the increase of planting scale,the adjustment of planting structure and the change of planting method,the diseases and insect pests of maize are gradually aggravated.However,seed treatment technology is to coat the surface of seeds with pesticide active ingredients by physical,chemical or biological methods to effectively prevent and control the occurrence of diseases and insect pests and ensure the healthy growth of crops.Since Spodoptera frugiperda invasion of China,the S.frugiperda has caused serious damage to the maize,mainly affecting the core leaves and growing points of the maize.At present,the S.frugiperda is mainly controlled by chemical pesticides.Because before the invasion of China,the S.frugiperda has gone through the prevention and control of pesticides in many countries,leading to the development of different degrees of resistance to chemical pesticides.Therefore,it is urgent to develop new,efficient and environmentally friendly pesticides and application technologies to solve the difficulties faced by existing pesticides.In this paper,we studied the effect of carbosulfan,acephate,chlorantraniliprole,and cyantraniliprole seed dressing or seed coat treatment on the safety of maize seeds,potting and field control efficacy and the amount of pesticide residues in maize,and the prevention of carbosulfan after inoculation with arbuscular mycorrhizal fungi controlling the influence of S.frugiperda and the residue of carbosulfan in maize,clarified the safe dosage of pesticides,the control effect and retention period of S.frugiperda,and the distribution and transmission of pesticides in maize.Comprehensive evaluation of the long-term significance of pesticides in the prevention and control of S.frugiperda and the application prospects of arbuscular mycorrhizal fungi in sustainable agricultural systems.1.The results showed that the seed coated or dressed 3,4,5ga.i/kg carbosulfan,2.5,5,10ga.i/kg acephate,0.5,1,2ga.i/kg cyantraniliprole,3+1,4+1,5+1ga.i/kg carbosulfan+chlorantraniliprole,3+1,4+1,5+1ga.i/kg carbosulfan+cyantraniliprole,2.5+1,5+1,10+1ga.I/kg acephate+chlorantraniliprole,2.5+1,5+1,10+1ga.acephate+cyantraniliprole had no effect on the indoor germination rate and seedling emergence rate of maize seeds.The seed coated or dressed 0.5,1,2ga.i/kg chlorantraniliprole significantly affected germination rate and emergence rate.After 3-5 days of potting,all the treatments of seed coating had significant effect on the aboveground and underground biomass of maize,but after 7 days,there was no significant difference between the two groups.2.The results of pot and field experiment showed that the control effect of seed coat treatment was always significantly higher than that seed dressing treatment at the same dosage;Seed coated or dressed 3,4ga.i/kg carbosulfan had a good control effect,which were still over 75%after 30 d,and the duration of validity was about 45 days.The control effect of acephate combined with chlorobenzamide could be improved.The control effect of seed coated 2.5ga.i/kg and 5ga.i/kg acephate can reach more than 80%.The results showed that the highest control effect was 75.08%in the treatment of cyantraniliprole,but it did not show synergistic effect when it was mixed with acephate,and it showed synergistic effect when it was mixed with carbosulfan.3.The residue distribution of carbosulfan and acephate in maize treated with seed dressing and seed coating increased rapidly to the maximum value in the early stage,and then decreased gradually to undetectable value with the passage of time.Carbosulfan and acephate were distributed in leaves>soil>roots,and the content in leaves and roots was always higher in seed coating than seed dressing,and the content in soil was always higher in seed dressing than seed coating.4.Inoculation of arbuscular mycorrhizal fungi could promote the growth of corn root system and increase the biomass of leaves,stems and roots.At 7-14 days,there was no difference in the content of carbosulfan in the root,stem,root and soil in NAC,G.mC and G.iC group.After 21 days,the concentrations of carbosulfan in the leaves,stem,root and soil of NAC control group were 1.33,0.28,0.52,0.58 mg kg-1,G.mC group were 1.91,0.37,0.68,0.51 mg kg-1,and G.iC group were 2.63,0.44,0.80,0.425 mg kg-1,respectively,there were significant differences among the treatments.The addition of arbuscular mycorrhizal fungi could significantly increase the content of carbosulfan in corn and decrease the content in soil.5.Inoculation of arbuscular mycorrhizal fungi promoted the transfer of carbosulfan from soil to plant.At 7-14 days,there was no significant difference in the transfer rate from soil to plant between NAC,G.mC and G.iC.In 21-49 days,the maximum transfer rate of NAC treatment from soil to root was 0.93,while that of G.mC and G.iC treatment was 1.34and 1.89;the transfer rates of NAC,G.mC and G.iC treatment from root to stem were all stable at 0.54;the maximum transfer rate of NAC treatment from stem to leaf was 4.63,while that of G.mC and G.iC treatment was 5.24 and 5.98 respectively.6.The amount of the two mycorrhizal fungi promoting the absorption and accumulation of carbosulfan was also different.Compared with NAC treatment,the content of carbosulfan in the soil of G.mC and G.iC treatment was always less than 1,which accelerated the degradation in the soil;Compared with NAC treatment,the content of carbosulfan in the root of G.mC treatment was 1.01-1.29,and G.iC treatment was 1.02-1.51;Compared with NAC treatment,the content of carbosulfan in the stem of G.mC treatment was 1.00-1.28,and G.iC treatment was 1.01-1.52;Compared with NAC treatment,the content of carbosulfan in leaves of G.mC treatment was 1.00-1.45,and G.iC treatment was1.01-1.97.7.In Guangzhou,the control effect of G.mC and G.iC on S.frugiperda was 87.07%and96.09%,respectively increased by 11.24-34.70%and 21.42-55.28%.In Nanning,the control effect of G.mC and G.iC on S.frugiperda was 86.09%,96.58%,increased by 9.17-36.73%and 21.77-53.76%respectively.Inoculation of arbuscular mycorrhizal fungi can significantly improve the control effect of carbosulfan on S.frugiperda.In conclusion,seed coat treatment could improve the content of insecticides in corn and the control effect on S.frugiperda;seed coat treatment could better prevent and control the occurrence of S.frugiperda compared with seed dressing;it was clear that inoculation of arbuscular mycorrhizal fungi can promote the absorption and transmission of carbosulfan,accelerate the degradation of carbosulfan in soil and improve the effective utilization of carbosulfan and improve the control effect on S.frugiperda. |
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