| Potato bacterial stalk rot is a new disease in potato production areas in Inner Mongolia,Guangxi,Guangdong,Hebei,Shaanxi and other places in recent years.With the continuous expansion of the planting area,the harm of potato bacterial stalk rot has increased year by year trends have seriously affected potato production and economic benefits.The typical symptom of the disease is brown to dark brown soft rot at the base of the potato stem,and the leaves of the plant wilt;the base of the stem breaks and tears later,causing the plant to die.Therefore,this experiment carried out pathogenic bacteria isolation and identification and biological characteristics research on potato bacterial stalk rot,and carried out laboratory virulence determination and field control efficacy tests of several drugs,and at the same time conducted inoculation of diseased potato as the diseased body In order to provide a basis for reasonable and effective disease prevention and control,the research on the source of the initial infection was carried out.The research results are as follows:1.Samples of stem rot disease collected in Wuchuan County and Shangdu County of Inner Mongolia were isolated and pathogenic bacteria were identified to determine the pathogen as Pectobacterium carotovorum subsp.brasiliense.Biological characteristics studies show that the optimal growth pH of the pathogen is 6.5～7,the optimal growth temperature is 28℃,and the optimal carbon source and nitrogen source are mannitol and ammonium sulfate,respectively.2.The results of the primary infection source test showed that the planting of seed potato can cause 66.67%of plant morbidity,and the planting of overwintering disease residues can cause the plant morbidity of 41.67%,which can be used as the source of initial infection to infect potatoes.The knife-borne disease transmission test showed that after the knife was used to cut diseased potatoes without disinfection,the disease-free seed potatoes could continue to be cut,which could spread healthy seed tubers and rot in the soil without emergence.The plant morbidity rate was as high as 53.33%.3.The disease resistance test results of different potato varieties showed that among the 18 main potato varieties tested,the high-sensitivity varieties were Favorita,Zhongjia 2 and Ji Zhangshu 12,and the high resistance varieties were Kexin 1 and Qing.Potato 9.4.Screen out 3 kinds of fungicides to inhibit the pathogenic bacteria.Laboratory virulence measurement showed that 0.3%tetramycin,80%elicin and 1.8%caprylate acetate had good bacteriostatic effects,with EC50 values of 5.73μg/mL,140.72 μg/mL and 696.92 μg/mL,The correlation coefficient r is greater than 0.9.The results of the synergistic test of the three kinds of compounding agents show that tetramycin and ethyl allicin are mixed according to the volume ratio of 5:5,7:3,3:7,4:6.Mixture of hexamectin acetate in volume ratios of 3:7,4:6,and 1:9,virulence ratio of mixture of alimentin and hexamectin acetate in volume ratio of 8:2 is greater than 1.5,with an increase effect.Through the application of high-concentration tetramycin fungicide,octamectin acetate fungicide,and allicin fungicide to seed potatoes,the results show that it has a certain inhibitory effect on seed potatoes.5.The field pesticide test showed that the single agent tetramycin and the allicin fungicide have better disease prevention effect,with the prevention effects of 69.14%and 52.31%,respectively,and the antibacterial effect of caprylate acetate on the disease was 27.28%;mixed in the formulation,the volume ratio of tetramycin to ethyl allicin is 7:3,which has the best disease prevention effect,72.34%,and the highest yield per potato is 33.11t/hm2.The output of each treatment is significantly different from the control. |
PDF Full Text Request