Identification Of Root-Knot Nematode And Screening Of Nematicides For Controlling It In Processing Peper In Heshuo County,Xinjiang

Heshuo County was an important processed pepper producing area in Xinjiang.In June2020,the plant nematode research group of Xinjiang Agricultural University found that the root-knot nematode infestation harms processed peppers in Heshuo County,Xinjiang.As one of the important pathogens,root-knot nematode could cause stunted growth of processed pepper plants,dwarf plants,and even death of plants.It has become an important factor restricting the yield and quality of processed peppers in Xinjiang.In this paper,the processed pepper plants in the main production areas of processed peppers in Heshuo County,Xinjiang were investigated and sampled,and the pathogenic plants were identified based on the morphological and molecular characteristics of the nematodes.Root-knot nematode disease indoor potted plants and field chemical control experiments were carried out,and the following main results were obtained:1.Identification of perineal patterns,morphological gauges,and specific primers（Mh-F/Mh-R）of root-knot nematodes in Heshuo County,the identification results shown that identified as Meloidogyne hapla.2.The effects of 3 single doses of Fluopyram、Fluazaindolizine and Avermectins and 9complex preparations on the second instar larvae and eggs of R.borealis were determined by laboratory toxicity test.The results showed that in the single-dose treatment,Avermectins had the highest toxicity to the second instar larvae of Meloidogyne hapla,with an LC₅₀of 0.6573mg·L^-1;fluopyram had the highest toxicity to nematode eggs,with an LC₅₀of 0.2213 mg·L^-1.In the screening of the drug ratio,1.8%abamectin EC:50%Fluazaindolizine Avermectins SC（1:1）had the most significant synergistic effect on the lethal effect of the second instar larvae and eggs of R.borealis.The toxicity coefficients were 152.54 and 134.39,respectively.The research results would provide a theoretical basis for better control of northern root-knot nematode and the development of mixed nematicides.3.The control effect of 8 different chemicals on root-knot nematode disease of pepper was tested by indoor pot method.The results showed that the relative control effect of pre-emergence application Avermectins-Fosthiazate and post-emergence application of abamectin was the best,which could reach 100%.Next,the application Avermectins-Fosthiazate,Fluazaindolizine,Fluopyram,and Pochonia chlamydosporia,Oligose-Fosthiazate,and post-emergence application of Avermectins-Fosthiazate,Fluazaindolizine and other 7 treatments,the relative control effects were all over 90%,while the relative control effect of post-emergence application of Paecilomyces lilacinus was the lowest that is 0%.The research results could provide a reference for the selection of field disease control agents for processing pepper root-knot nematode disease.4.The effects of 8 kinds of nematicides on the growth and yield of processed pepper and the control effect on the root-knot nematode disease of processed pepper were clarified through field chemical experiments.The results showed that the control effects of Avermectins-Fosthiazate and Pochonia chlamydosporia were the highest,reaching 96.1%and95.6%,respectively.And the two kinds of agents had a promoting effect on the growth of pepper,and the yield was increased compared with the blank control,with an increase of 7.9%and 7.6%,respectively.The research results could provide reference for the control of root knot nematode disease of processed peppers in Heshuo area.