Occurrence And Control Of Chinese Water Chestnut Stem Blight Caused By Phoma Bellidis

Water chestnut stem blight is a new disease caused by P. bellidis. This investigates varieties of water chestnuts that are resistant to Phoma stem blight, the characteristics of pathogen infections, incidence of the disease, study the technical aspects of the law as well as disease prevention and treatment of disease occurrence, the results were as follows;1) Pathogen infection characteristic findings show that, under no circumstances stab stalk, seeded6h spores germinated spores can produce1to3bud tube, inoculated12h germ tube can be observed beginning invade host cells, mainly through direct invasion and invasive germ tube like structure attached to the extracellular epidermal cells, guard cells, rarely invade through the stomata, seeded96h mycelium fills the host surface; stabbed in the stem, the spores3h began to germinate spores can produce1to3bud tube, vaccination can be observed6h germ tube began to invade, mainly through wounds penetrated, but also through invasive germ tubes and similar structures appressorium direct invasion of epidermal cells to defend cells, rarely invade through the stomata,48h mycelium full host surface; spores infect the host when, among spores can be fused by germ tube, while producing spores and hyphae adhesive substances around-cell extracellular matrix. Disease-resistant varieties can be obtained from water chestnuts and water chestnuts infection characteristics observed susceptible species vaccinated at the same point in time, the susceptible Lushan water chestnuts spore germination rates than resistant varieties Xiangtan water chestnuts spore germination rate, but no significant difference sex; vaccination at the same time, the success rate of invasive water chestnuts that LuShan susceptible varieties than XiangTan resistant varieties greater, and there are significant differences.2) Sick deformed mycelium overwintering survival test results showed that,25℃and4℃in favour of mycelium winter, winter sick deformed at room temperature within25℃,110d after the mycelium survival rate was10.8%; in within4℃ winter,110d after mycelium survival rate was6.1%. Under each condition mycelium outdoor survival rate is very low, and buried under the soil deeper, lower mycelium survival. Plant debris on the soil surface outdoor wintering,110d after the mycelium survival rate was2.8%;10cm under the soil surface overwinter survival of pathogens for110d;20cm below the soil surface overwinter survival of pathogens for94d.3) Consolidated2012and2013field survey results dynamically disease occurs, Eleocharis dulcis leaf blight occurs in the field, water chestnuts transplanted to field to mid-August for the early onset of the disease, there is a small lesion appeared, the disease means between0-0.116; late August to mid-September to mid-onset disease, lesions began to increase disease refers to between0.204~1.544; peak incidence of disease, lesions produce sharp end of September to the end of October, the incidence may be formed peak between1.108~7.815disease refers, stable condition after the November low. Disease index with temperature water chestnuts stem blight occurrence was negatively correlated (P<0.05), with the accumulated rainfall positively was correlated (P<0.05), and with relative humidity was no significant correlation.4) Evaluation of the results of resistance Water chestnut stem blight varieties showed different water chestnuts. water chestnuts indoor vitro inoculated with different varieties, Yang Dian water chestnuts and Xiangtan water chestnuts in strongest resistance, Jiangxi water chestnuts and Yiyang water chestnuts chestnut-resistant house Secondly; most susceptible are ShaoGuanMaBa water chestnuts and Lushan water chestnut, followed by a susceptible Bao Ying water chestnuts, SanJiang (98) water chestnuts and qizhou water chestnut. According to the findings of two years of field condition,33water chestnuts species, differences in disease resistance, application smallest deviation from the mean squared and analysis of33varieties of chestnuts clustering, clustering in R2=0.865under the level of33for varieties can be divided into three categories, class I:resistant varieties of nine varieties, disease refers to between0.02~0.57; class II:the resistant varieties of the22varieties, disease index ranged from0.7~1.25between; class Ⅲ: the susceptible of two cultivars, disease index were2.05and2.12respectively.5) Prevention efficacy results showed that9kinds of fungicides on Water chestnut stem blight indoor antibacterial test,400g/L flusilazole EC,10%difenoconazole WG,206.7g/liter flusilazole/famoxadone EC,25%carbendazim WP and70%Mancozeb WP inhibition better; pot efficacy test results show that the water chestnuts stalk were inoculated after2d spraying drug agents than inoculated before1d spraying drug agents with7d and10d survey control effect is good. On the stem10days after spraying before inoculation ld findings,206.7g/1flusilazole/famoxadone EC on the best control effect, efficacy was57.9%; at2d after inoculation spraying Pharmacy10days investigation,206.7g/1flusilazole/famoxadone EC on the best control effect, efficacy was46.63%Chemical control of field tests showed that206.7g/1flusilazole/famoxadone EC control effect better control effect was90.84%, there are significant differences with the other four kinds of agents.25%carbendazim WP,400g/L flusilazole EC,10%difenoconazole WG and70%Mancozeb WP control effect, there is no significant difference between control effects were73.25%,69.60%,64.84%and63.01%.