Study On The Synergistic Application Of Biocontrol Strains And Fungicides To Control The Rhizome Rot Of Ginger

Ginger is an important economic crop.In recent years,the planting area of ginger has increased year by year,and the occurrence of ginger rhizome rot has become increasingly serious.As a result,the yield and quality of ginger have been affected,causing significant economic losses.This study,through the collection of the diseased ginger plants,on the basis of isolation,culture and identification of pathogeny,carried out an indoor antibacterial effect test of nine biocontrol bacteria and 14 chemical fungicides,namely,a pot test with the combination of biocontrol bacteria and chemical fungicides.The results provide technical support for reducing pesticide application to control ginger rhizome rot,and provide a theoretical basis for further research and development of biological agents the occurrence of biocontrol agents.The main findings are as follows:1.In this experiment,27 strains of typical ginger rhizome rot symptoms were collected from Weifang Anqiu,and FM 1-1,FM 2-1,FM 2-2,and FM 3-2 strains were obtained after separation and purification.The morphological observation and molecular biological identification were used to identify FM 2-2,FM 3-2,and the identification results of both methods were shown as Pythium myriotylum.Then the phylogenetic tree was constructed based on the ITS sequence,and the result showed that the pathogen FM 2-2 clustered with Pythium myriotylum and Pythium zingiberum on one branch.2.9 kinds of collected biocontrol bacteria were identified by culture characteristics and molecular biological identification.The results showed that LM,LV,K1,K5 strains were Bacillus subtilis,J3 and J4 were Pseudomonas aeruginosa,B6 was Burkholderia pyrrocinia,D2 was Bacillus pumilus,and M strain was Trichoderma virens.3.Pathogenic fungi and antagonistic bacteria were screened by using plate confrontation and growth rate method.It was found that B6,J3,J4 and K5 had transparent antibacterial zone,among which the B6 strain had the best bacteriostatic effect with a bacteriostatic rate of90.88%.4.The compatibility of 14 chemical fungicides and 4 biocontrol bacteria was determined by diffusion method.The results showed that only a few treatments had obvious inhibition zones,and most of the selected chemical fungicides had little effect on biocontrol bacteria.5.The inhibitory effect of chemical fungicide on the biocontrol fungus M strain was determined by the plate confrontation method.The results showed that most of the chemical fungicides could inhibit the M strain,and the weakest inhibitory effect was 80%phosethyl-Al,with inhibition rate of 5.13%.6.This test determined the inhibitory effect of chemical fungicides and biocontrol bacteria on pathogen of ginger rhizome rot.The test results showed that the inhibition rate was positively correlated with the concentration of fungicides.There were significant differences in the antibacterial effects of different chemical fungicides,99%hymexazol had the strongest antibacterial effect,and the EC₅₀0 was 1.2407mg/L.There were some differences in the bacteriostasis of four different biocontrol bacteria.The antibacterial activity of LV,J3and B6 was close to each other at the same concentration,and K5’s antibacterial effect was weaker.7.The inhibitory effect of biocontrol bacteria and chemical fungicides on the pathogen of ginger rhizome rot were determined.The results show that the compound of chemical fungicides and biocontrol bacteria had better antibacterial effect than the single treatment,and the antibacterial effect could be up to 100%.8.In the experiment,a combination of four biocontrol bacteria and chemical fungicides was selected for the pot experiment.The results showed that the disease-control effect of the combination of biocontrol bacteria and chemical fungicides was higher than that of single treatment,and the highest disease-control effect could reach 77.32%.At the same time,the compound of biocontrol bacteria and chemical fungicides increases the plant height and stem diameter of ginger,and has a certain growth promoting effect.9.The effects of biocontrol bacteria and chemical fungicides treatment on the activities of defense enzymes POD,PAL and PPO were further determined by pot experiment.The results showed that the variation trends of enzyme activity in each group were generally the same,and the activities of defensive enzymes in the treatment group of biocontrol bacteria and chemical fungicides were generally higher than those in the blank control group and the single treatment group.,which improved the disease resistance of the ginger plants.