The Research Of Angelica Anthrax-angelica New Diseases

Angelica anthrax is a new disease that could harm the angelica. By investigation,we have found that this disease has spread in many main producing areas in Dingxicity, Gansu province.This disease has seriously affected the yield and the quality ofangelica. Therefore, taking the picked disease plant from the producing areas inDingxi, Gansu province as the experimental material object and combining theoutdoor investigation and indoor research, this study contributes to a systematicresearch on the separation and identification of angelica anthracnose pathogen,biological characteristics, mode of transmission, pathogenesis regularity and toxicitymeasurement of research. The main results are as follows.1. The symptoms and pathogen identificationThe results of field investigation between2012and2013shows that the majordamage of this disease is to the plant stem. At the initial stage of the disease, manylight brown spots appear on stems, and then expand to dark brown rectangular lesions,leaf chlorosis and wilting. Stems gradually dry up from outside to inside, and thenabundant of black acervulus scatter on spots. At last the plant will die. The indoorpotted plants inoculation test shows that the strain is the pathogenic bacteria.Throughthe indoor pathogenicity test, morphology and ITS sequence analysis we determinethat the pathogen ofAngelica anthrax is Colletotrichum dematium(Grove).2. The research of biological characteristicsPathogen biology determination results show that the temperature limit of myceliagrowth is10~35℃, the optimum temperature is25℃.The temperature limit ofspore germination is10~35℃, the optimal temperature is25℃.The pH of themycelia growth is5~11, the optimum pH is11, the pH of spore production is8~11,the optimum pH is10.The adaptability of spore germination is very strong, so it cangerminate in weak acid, neutral and alkaline conditions.And germination rate couldreach more than80%after14h.It can be good use of glucose, sucrose, lactose,maltose, mannitol, D-Arab seven kinds of carbon sources, but mannose, D-galactose and chloralose as bad carbon source has inhibitory effect on the growth ofhypha.In the determination of15kinds of nitrogen source, L-leucine, soy peptoneand other13kinds of nitrogen sources can be good use for mycelial growth.Conidium can germinate when the relative humidity is more than95%, and thegermination rate is the highest in liquid water.After12h it can reach more than 80%.The concentration of sucrose solution in1:5,1:10and1:20can promote thespore germination, and the concentration of potato juice1:5,1:10can inhibit thegermination. Light has no effect on mycelial growth and spore germination.3. The intrusion ways and occurrence regularity ofAngelica anthraxThe indoor potted plants inoculation test shows that puncturing, root-irrigationand spraying with conidial suspension can all cause disease. Puncturing will cause themost severe symptom. Spraying with suspension will lead to the lightest symptom. C.dematium can infect Angelica through wound, root and aerial parts. This disease startsfrom middle or late of June, and reaches peak late August or early September. Fieldtemperature and relative humidity is significantly positive correlation with diseaseincidence and index,which means that high temperature and high humidity could leadsevere disease and the impact of humidity on disease is greater than temperature.4. The toxicity measurement ofAngelica anthrax indoorThe test result of seven kinds of bio-control bacteria confrontation show that thebacillus subtilis B1and B2, bacillus amyloliquefaciens S27and O47,and Qing weibacillus O72have good inhibition for the pathogen.The7kinds of chemical pesticidetoxicity measurement results show that besides propineb,several other agents alsohave good inhibitory effect to pathogens. The EC50of difenoconazole, tebuconazoleand flusilazole are very low, respectively are2.14g/ml,8.21g/ml,14.13g/ml andthey can be priority to choose in the prevention and control of the field.According to the above test results, the five kinds of medicament concentrationof carbendazim, tebuconazole, Azoxystrobin, difenoconazole and difenoconazolemixed whit B1, B2, S27, O47, O72was carried out, the test results show that the lowconcentration of carbendazim, tebuconazole,difenoconazole and difenoconazolecombine with5kinds of bio-control bacteria, can greatly improve the effect ofbio-control of pathogen bacteria on the premise of reducing the use of chemicalpesticide use.Azoxystrobin with O72mixed effect is not obvious, but mixed withother four kinds of bio-control bacteria can also achieve good inhibitory effect.This research is the first systematically report in angelica anthrax symptom,pathogen, occurrence regularity,the route of transmission, and the determination ofvirulence test.This study enriched the medicinal plant disease research content, and provided the theoretical basis to identify the disease, pathogen identification andprevention and cure.Meanwhile,it has a vital significance for controlling this diseaseand producing green angelica.