Identification And Field Control Of Root-knot Nematodes In Main Producing Areas Of Coryneria Yunnanensis

Meloidogyne spp.is an important plant pathogen worldwide,annual economic losses exceed $8 billion.Root-knot nematodes are widely distributed and have a wide host range.Damage has been reported across Yunnan,especially in Chinese medicinal materials.Ludian,Lijiang,as the hometown of cloud medicine,is an important main producing area of cloud wood fragrance.In recent years,it has suffered from root knot nematode disease,which has resulted in annual decrease or even no harvest.In this study,root knot nematode disease in the main producing areas of the Chinese herbal medicine radix codendron was taken as the research object,to investigate the incidence,disease index,analysis of nematode infection source of weeds around habitat;It was identified by morphological characteristics and molecular biological characteristics.The laboratory efficacy experiments were conducted to screen the drugs and field control effects were studied,which provided practical basis for the prevention and control of root-knot nematodes in the main producing areas of C.yunnanensis.The main results are as follows:(1)Five kinds of Chinese medicinal materials in the main production area of Yunmuxiang are seriously damaged by root knot nematodes.The highest incidence rate of root knot nematode disease in the main production area of Yunmuxiang is 80%,and the lowest incidence rate is 30%.The incidence rate of affected plots in the whole township is more than 50%,and the incidence rate in some areas is 86%.The economic loss is 9260 yuan/mu.(2)The symptoms of the disease are mainly in the root,and a large number of rice granular or spherical root knots of different sizes are formed in both the taproot and fibrous roots.Morphological and molecular biological characteristics were used to identify Identification of 5 Chinese medicinal herbs,2 weed sources,and root knot nematodes in the main production area of Yunmuxiang through morphological and molecular biological characteristics showed that they were all northern root knot nematodes(M.hapla).Root knot nematode disease has become a major disease in the local area,and weeds in the field have become an important intermediate host,which seriously threatens the healthy development of local Chinese medicinal materials and causes local economic depression.(3)Avermectin,which had the best inhibition effect on the second instar larvae of root-knot nematodes,was screened by laboratory efficacy test.The fatality rate of nematodes was 72.787%.Followed by fluopyramide,phosphine thiazole;The fatality rate of C.elegans was 69.620%,63.576%,The fatality rate of nematode was 55.807%.The last was matrine,the fatality rate of C.elegans was 31.013%.(4)In the field control experiment,the best control effect of 5 chemical agents was phosphine thiazole,the best control effect was 80.56%,the disease index was 5.83,the pest reduction rate was 95.89%,and the pest control effect was 90.10%.Followed by abamectin,fluopyramide,the control effect of 72.22%,70.78%;The disease index was8.33 and 9.25,respectively.At last,matrine and nimeide were 44.44% and 25.00%,respectively.The disease index was 16.67 and 22.50,respectively.Among the 8biological pesticides,the best control effect was: T4 Dikosha,the control effect was69.44%,the disease index was 9.17,the incidence was 33.33%,The second was wireless double crop treasure,the compound agent for controlling nematodes,the control efficiency was 61.11%,58.33%;The disease index was 11.67,12.5;The third was purpura violacea,the control effect was 52.78%..The average insect content of soil was21.745 insects per 100 g soil,and the average insect population reduction rate was83.025%.In conclusion,this study clarified the pathogen classification status of root knot nematodes of different Chinese medicinal materials in the main producing areas of C.yunnanensis,screened and determined effective prevention and control agents,and provided a scientific basis for the effective prevention and control of root knot nematodes of C.Yunnanensis and other Chinese medicinal materials.The results of this study will provide a theoretical basis for the formulation of targeted prevention and control measures,and is of great significance for the healthy development of Chinese medicinal materials industry in Ludian,Lijiang.