【作者】 陈志敏；

【导师】 张绍升；

【作者基本信息】 福建农林大学 ， 植物病理学， 2009， 硕士

【摘要】 烟草根茎病害是烟草根部和茎部病害的总称,福建烟区每年由此类病害造成的损失相当严重。2006～2008年对福建烟草根茎病害进行调查研究,并对根茎病害防治药剂进行筛选和防治试验,以期为有效防治烟草根茎病害提供依据,取得以下主要结果:1.对福建烟草主产区的烟草根茎病害进行了系统的调查与鉴定:通过症状观察、病原菌分离、鉴定及致病性测定,明确了福建烟草根茎病害种类主要有:烟草镰刀菌根腐病(Fusarium sp.)、烟草青枯病(Ralstonia solanacearum)、烟草猝倒病(Pythium aphanidermatum)、烟草立枯病(Rhizoctonia solani)、烟草茎部炭疽病(Colletotrichum gloeosporioides)。明确了烟草镰刀菌根腐病和青枯病是福建烟草上的主要根茎病害,并对烟草不同根茎病害症状特征进行了描述与区别。2.明确了烟草黑胫病(Phytophthora parasitica var. nicotianae)在福建烟区的发生状况:在所调查的烟草主产区未发现烟草黑胫病,建议在福建烟草生产上不宜提倡全面防治黑胫病。3.在福建烟区首次发现烟草镰刀菌根腐病,并对其进行较为系统的研究:在调查中发现烟草镰刀菌根腐病是重要的根茎病害,发病率约20.0%,发生期为4月至5月。从烟草镰刀菌根腐病株分离到3种镰刀菌,经形态学鉴定为尖孢镰刀菌(Fusarium oxysporum)、茄病镰刀菌(F. solani)、半裸镰刀菌(F. semitectum);致病性测定表明3种镰刀菌均可侵染烟草,其中尖孢镰刀菌致病性最强,是引起田间根腐病的优势病原种群。尖孢镰刀菌生物学特性研究结果表明:尖孢镰刀菌生长发育适温为25～30℃;pH5～7适宜病原菌菌丝生长、产孢及孢子萌发。由尖孢镰刀菌对福建主栽烟草品种K326、翠碧1号、云烟87的致病性测定结果表明:3个品种均为感病品种。4.对烟草主要根茎病害病原菌进行化学药剂的初步筛选:平板抑菌试验及盆栽试验结果表明:58%甲霜灵锰锌WP对烟草猝倒病菌具有较强的抑制效果,EC50为15.8μg·mL-1,盆栽相对防效达93.3%;90%强氯精原药对烟草青枯病菌抑制效果较好,EC50为9.9μg·mL-1,盆栽相对防效为60.3%,显著优于生产上常用的农用硫酸链霉素,且具成本低、对环境无污染、无药害等优点,可进一步用于田间防治试验。10%世高EC和12.5%瑞毒脱EC对烟草立枯丝核菌、烟草炭疽病菌、烟草根腐尖孢镰刀菌均具有较强的抑制作用;由12.5%瑞毒脱EC和10%世高EC以3.2:1(有效浓度4:1)混配的12%复配剂EC对病原菌抑制效果最佳,复配剂1500X液盆栽防治效果显著,且成本较低。更多还原

【Abstract】 Tobacco root and stem diseases are the general name of tobacco root diseases and tobacco stem diseases, these diseases caused heavy losses in major tobacco production regions of Fujian province. Tobacco root and stem diseases were investigated and studied during 2006～2008 in Fujian, and the chemicals were screened for the control of tobacco root and stem diseases, expected to provide basis for control these diseases effectively. The results were as follows:1. Tobacco root and stem diseases were investigated and identified in major tobacco growing regions of Fujian. The major kinds of tobacco root and stem diseases were confirmed by symptoms observation, pathogens isolation and identification and pathogenicity test, these diseases include tobacco fusarium root rot, tobacco bacterial wilt, tobacco damping-off, tobacco sore shin, tobacco anthracnose. The results indicated that tobacco fusarium root rot and tobacco bacterial wilt were major root and stem diseases in Fujian tobacco growing regions, and the symptom characteristics of different tobacco root and stem diseases were described and differentiated.2. The occurrence of tobacco black shank was confirmed in Fujian tobacco growing regions, tobacco black shank was’t founded in Fujian tobacco growing regions where we investigated, as the results of investigated proposed that it’s not suitable for advocate overall control tobacco black shank in Fujian tobacco production.3. Tobacco fusarium root rot as a new disease was founded in Fujian tobacco growing regions and we were systematic studied of the disease. The results indicated that tobacco fusarium root rot was an important tobacco root and stem disease, incidence about 20.0%, occurrence period from April to May. Three kinds of Fusarium were isolated from the samples of tobacco fusarium root rot and were identified as Fusarium oxysporum, F. solani, F. semitectum by morphology. Results of pathogenicity test showed that all three Fusarium were able to infection tobacco, and F. oxysporum was the dominant pathogen that had stronger pathogenicity to tobacco than the others. F. oxysporum biological characteristic research indicated that the optimum temperature for growth of the pathogen was 25～30℃, the optimum pH value for mycelial growth, Sporulation and spore germination were in the range of 5～7. Rresistance of main cultivars to F.oxysporum was determined, the results indicated that Cuibi 1、K326、Yuyan87 all susceptible to F.oxysporum.4. Chemicals were screened for control the pathogens of tobacco root and stem disease by inhibitory tests in vitro and pot test, the results indicated that Metalaxyl-mancozeb 58% WP had good inhibitory effect on Pythium aphanidermatum, EC50 values was 15.8μg·mL-1, the control effect in pot test was 60.3%, Trichloroisocyanuric acid 90% had good inhibitory effect on Ralstonia solanacearum, EC50 values was 9.9μg·mL-1, the control effect in pot test was 60.3%, which significantly better than streptomycini sulfas 72% WP that commonly used in field, and have the advantages of low cost, non-pollution and non-phytotoxicity that can be further used in field control test. Difenoconazole 10% EC and myclobutanil 12.5% EC both have good inhibitory effect on Rhizoctonia solani, Colletotrichum gloeosporioides and F. oxysporum. 12% compounded agent EC was prepared by mixture 3.2mL 12.5% myclobutanil EC with 1mL 10% Difenoconazole EC( the ratio of effective concentration was 4:1) that had good inhibition effect on the pathogens, results of pot test indicated that 1500-fold of 12% compounded gagent EC had good control effect of tobacco root and stem diseases, and with low cost.更多还原