除草剂对南方根结线虫存活的影响

在离体恒温条件下,研究了7种蔬菜田常用低毒除草剂对南方根结线虫(Meloidogyne incognita)存活的影响,并进行了除草剂盆栽防效试验.结果表明:常用喷施剂量处理后,所有供试除草剂对南方根结线虫2龄幼虫(J2)及卵囊内卵的孵化均有不同程度的致死作用,其中以33%二甲戊乐灵EC和48%氟乐灵EC效果最为明显.并对这2种除草剂进行盆栽防效试验,结果表明:48%氟乐灵EC防效优于33%二甲戊乐灵EC,接近阿维菌素,并且覆膜的防效优于不覆膜.     

阿维菌素对南方根结线虫的生物活性

采用直接触杀法测定了阿维菌素对南方根结线虫的杀线活性。结果表明,1.8%阿维菌素EC对南方根结线虫具有很强的杀线活性,其LC50为1.48mg/L,而10%噻唑膦GR的LC50为13.90mg/L,表明1.8%阿维菌素EC对南方根结线虫的杀线活性明显高于对照药剂10%噻唑膦GR,具有广阔的应用前景和开发价值。     

苘麻提取物对南方根结线虫的活性

[方法]为寻找环境友好型杀线虫剂,测定了不同溶剂苘麻提取物对南方根结线虫的生物活性,对甲醇提取物进行生物碱粗分离,并对杀线虫活性强的碱水层进一步用极性从小到大的溶剂萃取,同时进行生物活性检测.[结果]12个萃取组分中氯仿与甲醇体积比为4∶1(A5)和1∶2(A8)两组分具有极强杀线虫活性,干粉质量浓度125g/L时,A5组分48h的线虫校正死亡率达100％,A8组分达932％.[结论]可对A5和A8组分进一步分离纯化和生物活性追踪.     

茼蒿甲醇提取物不同萃取组分对南方根结线虫发育的影响

采用液-液分配法对茼蒿甲醇提取物进行了萃取分离,得到石油醚、三氯甲烷、乙酸乙酯、正丁醇、水等5种不同萃取组分;采用室内培养和盆栽试验的方法,研究了5种萃取组分对南方根结线虫发育的影响。结果表明:茼蒿甲醇提取物水萃取组分对南方根结线虫胚胎发育和胚后发育的抑制作用最强。1%茼蒿甲醇提取物水萃取组分处理后264h,仅有15%的卵完成胚胎发育;胚后发育历程、初侵染、初产卵日分别推迟4、5、9d,雌虫产卵量显著降低。     

不同药剂复配对南方根结线虫增效作用

[目的]筛选对南方根结线虫高效低毒的药剂。[方法]采用浸泡杀线虫法测定9种药剂对南方根结线虫的毒力,选活性较高的单剂进行交互复配,测定其联合毒力。[结果]甲氨基阿维菌素苯甲酸盐对2龄幼虫和卵囊的毒力最强,LC50值分别为2.51、10.50 mg/L;甲氨基阿维菌素苯甲酸盐与噻唑膦复配的共毒系数为141.59,阿维菌素与噻唑膦复配的共毒系数为159.37。[结论]单剂以甲氨基阿维菌素苯甲酸盐活性最高,复配剂以噻唑膦与阿维菌素、甲氨基阿维菌素苯甲酸盐复配效果最佳。     

氯化苦与阿维菌素混用对南方根结线虫的室内活性评价

[目的]评价氯化苦与阿维菌素混用对南方根结线虫的室内防治效果。[方法]采用广口瓶熏蒸法和凹玻片密闭熏蒸法测定氯化苦与阿维菌素联合对南方根结线虫的毒力。[结果]广口瓶熏蒸试验和凹玻片密闭熏蒸试验表明,氯化苦和阿维菌素的4种不同用量混用均对南方根结线虫表现出增效作用,对南方根结线虫的校正死亡率均分别达到85%和93%以上。[结论]氯化苦与阿维菌素混用对南方根结线虫有良好的控制作用。     

曲霉发酵液对烟草根结线虫的作用

室内测定了一株曲霉发酵液对烟草根结线虫优势种群南方根结线虫（Meloidogyne incognita）2龄幼虫、卵囊和散卵粒孵化的影响。不同稀释浓度发酵液的处理和无菌水处理有显著差异,发酵液的1倍液以上浓度与10μtg／ml涕灭威的防效相当,对2龄幼虫的致死率在90％以上,对卵囊和散卵粒孵化的抑制率在95％以上。     

根结线虫生防菌SneF8代谢产物理化性质的初步研究

SneF8是沈阳农业大学北方线虫研究所从土壤中分离到的一株生防真菌,该菌株代谢产物能够有效控制南方根结线虫引起的蔬菜根结线虫病. 研究了温度及pH对该菌株发酵液中活性物质稳定性的影响;利用捷克 8溶剂系统纸色谱及pH纸色谱等方法对该菌株中活性物质的水溶性、离子特性等一些理化性质进行了早期鉴别. 结果表明:该发酵液中除了具有大量的强酸性,强极性,易溶于水等极性有机溶剂的活性物质外,还有部分的两性活性物质存在,为这一农用抗生素的进一步纯化和结构测定提供依据.     

4种杀线虫剂对南方根结线虫的室内活性测定

通过藏红T染色法,确定线虫染色时间,并测定4种常规药剂对南方根结线虫的室内活性。结果显示,染色1 h后,线虫的染色率达到100%。1.8%阿维菌素EC和40%灭线磷EC对南方根结线虫具有良好的活性,LC_(50)值分别为14.926 3 mg/L和15.306 8 mg/L;40%辛硫磷EC和200 g/L丁硫克百威EC活性较差。     

生防细菌J352对不同种类线虫的毒力差异

从黄瓜根际分离获得一株对多种病原真菌有较强抑制作用的细菌,用该细菌不同浓度的发酵液测定了对4种线虫的作用。结果表明,该发酵液呈微碱性,不同浓度发酵液对各种线虫均有较好的防治作用,并且毒力作用具有明显差异,对4种线虫的毒力大小顺序分别为小杆线虫、大豆胞囊线虫、根结线虫和腐烂茎线虫。     

酸类化合物对南方根结线虫的作用方式

[方法]采用室内离体测定方法,测定3种酸类化合物对南方根结线虫2龄幼虫毒力、死亡时间、运动行为、个体发育及体液外渗作用方式影响。[结果]3种化合物对2龄幼虫毒力大小为甲酸>乙二酸>柠檬酸,死亡时间长短为甲酸<乙二酸<柠檬酸,3种化合物均可抑制2龄幼虫运动行为和个体发育,并导致2龄幼虫体液外渗。[结论]供试化合物通过抑制线虫的运动、发育、促进线虫体液外渗等作用,破坏其正常生理代谢功能,致使线虫死亡。     

10%虫胺磷GR对人参榕根结线虫病的防效

利用10％虫胺磷GR对人参榕根结线虫病进行了防治试验。结果表明,10％虫胺磷GR66-7mg／L药液灌根或者配制成含200g／m^3的毒土,可有效地防治人参榕根结线虫病。     

球孢白僵菌Snf907发酵液对番茄根结线虫病的控病效果及防御酶活性影响

研究球孢白僵菌Snf907不同浓度发酵液对番茄幼苗期南方根结线虫病(Meloidogyne incognita)的室内防效,并测得处理后番茄幼苗根内几种主要寄主防御反应酶系PAL、POD、PPO、SOD和可溶性蛋白PRO活性的动态变化.结果表明:不同浓度的发酵液对根结和卵囊的抑制率均明显高于对照,其中原液和5倍稀释液达到80%以上.不同浓度发酵液处理后番茄幼苗根部的PAL、POD、PPO、SOD活性均高于对照,PRO活性显著增加.显示了球孢白僵菌在促进植物生长方面的潜能.     

Efficacy of a Chitin-Based Water-Soluble Derivative in Inducing Purpureocillium lilacinum against Nematode Disease (Meloidogyne incognita)

Plant-parasitic nematodes cause severe economic losses annually which has been a persistent problem worldwide. As current nematicides are highly toxic, prone to drug resistance, and have poor stability, there is an urgent need to develop safe, efficient, and green strategies. Natural active polysaccharides such as chitin and chitosan with good biocompatibility and biodegradability and inducing plant disease resistance have attracted much attention, but their application is limited due to their poor solubility. Here, we prepared 6-oxychitin with good water solubility by introducing carboxylic acid groups based on retaining the original skeleton of chitin and evaluated its potential for nematode control. The results showed that 6-oxychitin is a better promoter of the nematicidal potential of Purpureocillium lilacinum than other water-soluble chitin derivatives. After treatment, the movement of J2s and egg hatching were obviously inhibited. Further plant experiments found that it can destroy the accumulation and invasion of nematodes, and has a growth-promoting effect. Therefore, 6-oxychitin has great application potential in the nematode control area.     

Characterization of Five Meloidogyne incognita Effectors Associated with PsoRPM3

Root-knot nematodes (RKNs) are devastating parasites that invade thousands of plants. In this study, five RKN effectors, which might interact with Prunus sogdiana resistance protein PsoRPM3, were screened and identified. In situ hybridisation results showed that MiCal, MiGST_N_4, MiEFh and MiACPS are expressed in the subventral oesophageal glands (SvG), and MiTSPc hybridization signals are found in the dorsal esophageal gland (DG) of Meloidogyne incognita in the pre-J2. RT-qPCR data indicated that the expression of MiCal, MiGST_N_4, MiEFh, and MiACPS genes are highly expressed in M. incognita of pra-J2 and J3/J4 stages. The expression of MiTSPc increased significantly in the female stage of M. incognita. Moreover, all effectors found in this study localize in the cytoplasm and nucleus when transiently expressed in plant cells. In addition, MiGST_N_4, MiEFh, MiACPS and MiTSPc can elicit the ROS burst and strong hypersensitive response (HR), as well as significant ion leakage. Our data suggest that MiGST_N_4, MiEFh, MiACPS and MiTSPc effectors may be involved in triggering the immune response of the host plant.     

高毒力杀蚜白僵菌的分离及筛选

对不同地方采集到的被白僵菌侵染死亡的昆虫分离、纯化,以桃蚜、麦长管蚜和禾谷缢管蚜为供试昆虫进行毒力测定。结果表明不同菌株的致病力存在着明显的不同。致病力最强的为Bb2号菌株,在1.1×108个孢子/mL时,三种蚜虫的累计死亡率分别为:100%、96.3%、93.7%。