Investigation On Suaeda Liaotungensis Diseases And Pests And Researching On Pathogenic Fungus Biological Characteristies Of The Red Spot Disease

The Suaeda belongs to Chenopodiaceae genus suaeda and is annual herb. It is the typical of the saline-alkali soil indicator plant. It has edible values, medicinal values, fodder values et al. And it could to improve soil and Eco-environmental. S. is regarded as pioneer plants in saline-alkali soil improvement, is a great development value of natural resources. S. was considered rare diseases and pests.But, to investigated S. which grown on the Dalian seaside beach area, found that S. have the pest and diseases in natural habitats. Few reports in China and abroad,studied on the species of pests and diseases.This paper, S. pest and disease in Dalian seaside beach area, were investigated and identificated. S. red spot disease’s pathogenic fungus were identified and the biological characteristies were studied. To provide guidance for S. crop cultivation.Main study are as follows:(1) To investigated the species of S. diseases and pestit could occur red spot disease and white rot disease.S.red spot disease’s incidence rate is67%, condition index is37. S. white rot disease’s incidence rate is34%, condition index is16.4.From S.,found that incidence of gall is53%, flying out4kinds of tiny insects form the gall. Mainly for insects that were preliminary judged are Hymenoptera and Diptera.(2) Separation of single red spot disease’s spot, accessed SK-X1and SK-X2; Separation of single red spot disease’s spot, accessed SK-X3and SK-X4. Based on morphological characterization and molecular identification results:SK-X1is Pestalotiopsis clavispora and SK-X2is Colletotrichum; SK-X3and SK-X4are Alternaria.By Koch’s pathonomia determination of4kinds of fungal pathogens,all of the4have pathogeniciry.They can be seen S.s red spot and white rot disease’s pathogenic bacterias.(3) Biological characteristics of the S. red spot disease’s pathogenic fungus:The influence of the development of hypha growth:SK-X1and SK-X2optimal growth temperature is28℃. The lethal temperature of SK-X1mycelia is70℃,15min,SK-X2is73℃,15min.The optimum pH of two is7.SK-X1could be grown under RH86%-100%, SK-X2could be grown under RH65%-100%. And two strains’my celial could be grown fastest under RH100%, simultaneously two strains have the maximum sporulation quantity. SK-X1and SK-X2have the best sporulation under the full illumination. The Spore of two fungus could be germination under temperature15℃-35℃, optimum temperature is28.SK-X1’s spoe could be germination under pH5-10, the optimum pH is7. SK-X2’s spore could be germination under pH4-12, the optimum pH is7.The spore of SK-X1could be germinated under RH100%-90%,<90%no germination.The spore of SK-X2could be germinated under RH100%-86%,<86%no germination. All lighting condition has advantage to the sporulation of two strains. Nutrition conditions:Based on orthogonal test, SK-X1the optimum medium is sucrose15g/L、yeast extract2.5g/L、MgSO40.5g/L、VB10.75g/L; SK-X2the optimum medium is lactose17.5g/L、yeast extract7.5g/L、MgSO40.25g/L、VB10.5g/L(4)Antagonistic bacteria and chemical agent influenced on S. red spot disease’s two pathogens:Bacillus megaterium could inhibit the growth of phytopathogen SK-X1. Penicillium oxalicum could inhibit the growth of phytopathogen SK-X2.Bacteriostatic circle diameters respectively:4.69cm,5.14cm. And respectively, inhibition rate is65.25%,73.25%. Copper sulfate200μg/mL the inhibition rate on phytopathogen SK-X1and SK-X2were98%and86.1%respectively.Using70μg/mL chlorothalonil of filter paper, bacteriostatic circle diameter of SK-X1and SK-X2respectively are:4.81cm,5.23cm. Inhibition rate and59.4%and70.4%。Study on the determination of toxicity of chemical agent found that. Copper sulfate has the best inhibition of SK-X1mycelial growth,and has the best bacteriostatic efficacy, EC50is0.131806μg/mL. And copper sulfate has the best inhibition of SK-X2mycelial growth,and has the best bacteriostatic efficacy, EC50is1.331644μg/mL. Chlorothalonil has the inhibition of SK-X1and SK-X2,66.1421μg/mL,41.77507μg/mL respectively. In the study,found that antagonistic bacteria’s extracellular secretion and chemical agent have varying degrees of inhibition on the four isozyme activity.