长枝木霉对禾谷胞囊线虫卵的寄生和毒杀作用及其机制

为了明确长枝木霉Trichoderma longibrachiatum对小麦禾谷胞囊线虫Heterodera avenae卵的防治潜力和作用机制,在室内测定了长枝木霉分生孢子悬浮液对小麦禾谷胞囊线虫卵的寄生和毒杀作用,并通过温室盆栽试验测定了长枝木霉分生孢子悬浮液对小麦禾谷胞囊线虫卵的防治效果.室内试验中1.5×107 CFU/mL的长枝木霉分生孢子悬浮液处理12 d对小麦禾谷胞囊线虫卵的寄生率和卵孵化的相对抑制率分别为91.33％和88.35％.温室盆栽试验中1.5×107 CFU/mL处理对土壤中胞囊、线虫和根系中线虫的相对防治效果分别为89.84％、92.67％和88.30％;接种卵悬浮液和长枝木霉分生孢子悬浮液后,小麦幼苗株高、根系长度、地上部鲜重和根系鲜重的增长率分别为66.72％、159.31％、169.09％和170.19％;叶绿素总量和根系活力显著高于对照,分别为17.52 mg/g和356.25 μg·g-1·h-1.研究表明长枝木霉可作为小麦禾谷胞囊线虫的生防制剂.     

长枝木霉菌株TL16防治南方根结线虫的作用机理

为探明长枝木霉Trichoderma longibrachiatum菌株TL16防治南方根结线虫Meloidogyne incognita的作用机理,采用原生质体转化法获得绿色荧光蛋白(green fluorescent protein,GFP)标记菌株GFP-TL16,通过测定菌株TL16和GFP-TL16对南方根结线虫卵和2龄幼虫(2nd-stage juvenile,J2)的寄生与致死作用,其发酵液对卵孵化的抑制作用和对J2的致死作用,以及菌株GFP-TL16在黄瓜根系的定殖情况和菌株TL16对番茄根结形成的抑制作用来综合分析其作用机理。结果显示:菌株TL16菌丝对南方根结线虫卵无寄生作用,处理19 d后卵降解率为26.33%,致死作用较低;菌株TL16分生孢子悬浮液处理南方根结线虫J2后72 h的致死率为1.65%,且无寄生作用。菌株TL16发酵液处理南方根结线虫J2后48 h的校正死亡率为10.71%,处理卵15 d后对卵孵化的相对抑制率为77.11%。菌株GFP-TL16可定殖于黄瓜根系中,经菌株TL16处理后接种南方根结线虫J2,番茄根结减退率为55.88%。表明长枝木霉菌株TL16可通过抑制根结线虫卵孵化和诱导番茄产生抗病性来防治根结线虫病。     

木霉D5菌株的鉴定及其杀线活性测定

通过形态学和分子生物学方法鉴定了1株杀线木霉D5菌株的种类,并评价了其孢子悬浮液和发酵液对禾谷孢囊线虫Heterodera avenae 2龄幼虫的毒杀活性。结果表明,木霉D5菌株为绿色木霉Trichoderma viride(ITS序列登录号：OL661629;TEF序列登录号：ON241311)。浓度为1.0×10⁷ cfu/mL的D5菌株孢子悬浮液和发酵液原液处理2龄幼虫72 h后,线虫死亡率分别为85.20%和86.57%。在温度为20～80℃范围内以及pH为2～10时,发酵液均具有较高杀线活性。     

家蚕的一种微孢子虫对小菜蛾的致病力测定

测定了从家蚕体内分离的一种微孢子虫Vairimorpha sp.对小菜蛾的致病力。室内试验结果表明,当起始侵染期为小菜蛾2龄幼虫,浓度为1×10~6孢子/ml时对当代小菜蛾的致病力最高,幼虫的死亡率可达80.00％～82.67％,蛹死亡率可达50.00％～52.94％,而小菜蛾雌成虫的产卵量由对照的249.64～278.38粒/雌下降到120.56～126.72粒/雌,产卵量下降50％左右;当起始侵染期为3龄幼虫,浓度为1×10~6孢子/ml时,当代幼虫的死亡率只有40.00％～61.33％,与起始侵染期为2龄时相差很大,蛹死亡率和成虫每雌产卵量下降率与起始侵染期为2龄时差异不大。另外,家蚕微孢子虫还可通过垂直传染方式影响下代小菜蛾幼虫的死亡率。     

四脊裸孢壳Dh菌株对钩麦蛾和菜青虫的毒力

利用四脊裸孢壳Dh菌株不同浓度的分生孢子悬浮液处理钩麦蛾幼虫和菜青虫,进行室内毒力测定,分析Dh菌对钩麦蛾和菜青虫幼虫的作用。结果表明:Dh菌1×106、5×106、1×107、5×107个/mL和1×108个/mL 5种浓度分生孢子悬浮液对钩麦蛾和菜青虫幼虫均有致病力,致死中浓度钩麦蛾幼虫为4.426×106个/mL,菜青虫为1.279×107个/mL。     

芜菁夜蛾线虫对小木蠹蛾侵染能力的研究

1988年室内试验结果证明:芜菁夜蛾线虫的5个品系Agriotos、All、Mexican、NC 116、Florida对蛀干害虫小木蠹蛾幼虫有很高的侵染力;但不侵染蛹。用Agriotos品系作试验,剂量和温度影响小木蠹蛾的死亡率和致死速度。当剂量大于25条线虫/木蠹蛾幼虫时,死亡率可达92％以上,同一剂量对一年、二年生幼虫的死亡率差异不显著。在15-30℃的范围内,线虫均能侵染和杀死寄主,但30℃不能在寄主尸体内繁殖。25℃为线虫浸染的最适宜温度,寄主死亡率最高,死亡速度也最快。一头5龄和7龄木蠹蛾幼虫能繁殖侵染期线虫16万和48万头。在10℃低温中,线虫不能侵染寄主,但并不死亡,当移入适宜的温度后,能迅速恢复活动。在35℃高温中,线虫则很快死亡。     

斯氏线虫对进境原木上长林小蠹的防治试验

本文报道了斯氏线虫对进境原木上长林小蠹的生物防治试验.结果表明,斯氏线虫对长林小蠹的侵染力较强.通过毒力测定,斯氏线虫对长林小蠹3龄幼虫的LD50、LD99分别为21、432(条/头),而对蛹的LD50、LD99分别为12、230(条/头).在寄生强度测定中,斯氏线虫与长林小蠹3龄幼虫仅接触0.5h,每虫就可被侵入1.6条线虫,12h寄生的死亡率达到90%,24h寄生的死亡率为100%.斯氏线虫对长林小蠹表现出较高的致病性和寄生性.斯氏线虫在室内以浸泡法和淋施法防治长林小蠹的效果较好.     

球孢白僵菌MZ050724对亚洲玉米螟幼虫毒力测定研究

利用浓度为4.0×104、4.0×105、4.0×106、4.0×107、4.0×108个/mL的球孢白僵菌MZ050724分生孢子液对3龄和4龄的亚洲玉米螟幼虫进行毒力测定研究。结果表明,该菌株具有较高的杀虫活性。对3龄幼虫最高累计校正死亡率为88.65%,致死中浓度是(2.195±0.135)×104个/mL,致死中时间是(4.30±0.16)d;对4龄幼虫最高累计校正死亡率为85.75%,其致死中浓度(4.362±0.088)×105个/mL,致死中时间为(4.77±0.11)d。相比较对3龄幼虫的防治效果好于对4龄幼虫的防治效果。     

不同接种方式下球孢白僵菌对小菜蛾的致病力

本文比较了4种接种方式下球孢白僵菌Bb02菌株对小菜蛾2龄和3龄幼虫的致病力。当孢子悬浮液浓度为1×107个/mL时,球孢白僵菌对小菜蛾2龄幼虫校正死亡率为浸虫法73.79%,涂抹法68.28%,喷雾法51.72%和浸叶法33.79%;对3龄幼虫的校正死亡率为喷雾法57.93%,浸虫法57.24%,涂抹法55.86%和浸叶法28.28%,虽然浸虫法的校正死亡率稍低于喷雾法,但两者差异不显著。同时,2龄和3龄幼虫以浸虫法处理僵虫率最高,分别达31.25%和29.55%;致死速度最快,LT50分别为3.62 d和4.63 d。认为浸虫法最适于室内准确评价球孢白僵菌对小菜蛾的致病力。     

异小杆线虫D_1对迟眼蕈蚊侵染力的研究

本文报道6个昆虫病原线虫品系对危害韭菜的迟眼(?)蚊的侵染力,以Heoerorhabditissp.D_1的侵染力为最高。室内试验表明,当沙土中D_1线虫与裸露的迟眼(?)蚊幼虫的比为15:1时,幼虫死亡率可达81.8％.盆栽试验中益害比为38:1时,由于该幼虫大部分在韭菜茎内为害,寄生率仅35.1％,但对茎外的蛹寄生率可达82.7％.     

Parasitism of <Emphasis Type="Italic">Trichoderma</Emphasis> on <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> and role of the gelatinous matrix

Trichoderma (T. asperellum-203, 44 and GH11; T. atroviride-IMI 206040 and T. harzianum-248) parasitism on Meloidogyne javanica life stages was examined in vitro. Conidium attachment and parasitism differed beween the fungi. Egg masses, their derived eggs and second-stage juveniles (J2) were parasitized by Trichoderma asperellum-203, 44, and T. atroviride following conidium attachment. Trichoderma asperellum-GH11 attached to the nematodes but exhibited reduced penetration, whereas growth of T. harzianum-248 attached to egg masses was inhibited. Only a few conidia of the different fungi were attached to eggs and J2s without gelatinous matrix; the eggs were penetrated and parasitized by few hyphae, while J2s were rarely parasitized by the fungi. The gelatinous matrix specifically induced J2 immobilization by T. asperellum-203, 44 and T. atroviride metabolites that immobilized the J2s. A constitutive-GFP-expressing T. asperellum-203 construct was used to visualize fungal penetration of the nematodes. Scanning electron microscopy revealed the formation of coiling and appressorium-like structures upon attachment and parasitism by T. asperellum-203 and T. atroviride. Gelatinous matrix agglutinated T. asperellum-203 and T. atroviride conidia, a process that was Ca²⁺-dependent. Conidium agglutination was inhibited by carbohydrates, including fucose, as was conidium attachment to the nematodes. All but T. harzianum could grow on the gelatinous matrix, which enhanced conidium germination. A biomimetic system based on gelatinous-matrix-coated nylon fibers demonstrated the role of the matrix in parasitism: T. asperellum-203 and T. atroviride conidia attached specifically to the gelatinous-matrix-coated fibers and parasitic growth patterns, such as coiling, branching and appressoria-like structures, were induced in both fungi, similarly to those observed during nematode parasitism. All Trichoderma isolates exhibited nematode biocontrol activity in pot experiments with tomato plants. Parasitic interactions were demonstrated in planta: females and egg masses dissected from tomato roots grown in T. asperellum-203-treated soil were examined and found to be parasitized by the fungus. This study demonstrates biocontrol activities of Trichoderma isolates and their parasitic capabilities on M. javanica, elucidating the importance of the gelatinous matrix in the fungal parasitism.     

Improved attachment and parasitism of <Emphasis Type="Italic">Trichoderma</Emphasis> on <Emphasis Type="Italic">Meloidogyne javanica</Emphasis> in vitro

Monoclonal and polyclonal antibodies that bind to eggs and/or second-stage juveniles of the nematode Meloidogyne javanica were tested for their effects on the parasitic interactions between this nematode and the fungus Trichoderma. Parasitism of Trichoderma asperellum-203 and Trichoderma atroviride on nematode egg masses, eggs and juveniles was enhanced when antibodies were incorporated into in vitro parasitism bioassays. Parasitism on separated eggs (without gelatinous matrix) and their hatched juveniles was also improved, compared to controls without antibodies that did not attach fungal conidia. Improved parasitism could be due to bilateral binding of the antibodies to the nematodes and conidia, enabling better conidial attachment to the nematodes. Enhanced germination of antibody-bound conidia further improved parasitism. Differences were observed among antibodies in their effects on fungal parasitism and their interaction with Trichoderma species. We focused mainly on the egg- and juvenile-binding monoclonal antibody MISC that exhibited a stronger reaction with T. asperellum-203 than with T. atroviride. Pretreatment of this antibody with fucose inhibited its binding to nematodes and conidial attachment to nematodes, as well as conidial agglutination in the presence of the antibody. Antibody binding to juveniles affected their movement and viability, especially gelatinous matrix-originated juveniles. The fucose-specific lectin Ulex europaeus-I enhanced conidial attachment to nematode life-stages, and conidial agglutination occurred in its presence. These phenomena were inhibited by preincubating lectin with fucose. Our results suggest that carbohydrate residues, such as fucose, on the surface of the nematode and fungal conidia are involved in the antibody- and lectin-mediated improved parasitism.     

食线虫真菌蠕虫埃斯特菌对植物寄生线虫的侵染特性

为评价食线虫真菌蠕虫埃斯特菌Esteya vermicola菌株NKF 13222的生防应用价值,采用2%水琼脂培养基平板接种法测定了该菌株对7种植物寄生线虫的诱引、黏附和侵染能力,并比较了其对不同线虫的侵染特性.结果显示,该菌株的菌丝对松材线虫、拟松材线虫、腐烂茎线虫和水稻干尖线虫均有诱引作用,而对南方根结线虫、禾谷孢囊线虫和穿刺短体线虫无诱引作用;菌株的粘性分生孢子对有诱引现象的4种线虫都能黏附,接种24 h后的黏附率达到82%～99%,对无诱引现象的3种线虫不能黏附;粘性分生孢子黏附虫体后对不同线虫的侵染力存在差异,接种7 d后的松材线虫死亡率可达98%,而拟松材线虫、腐烂茎线虫和水稻干尖线虫死亡率分别为43%、35%和9%.表明蠕虫埃斯特菌不仅是松材线虫的强内寄生真菌,而且对其它重要植物寄生线虫也具有一定的应用潜力.     

安徽省潜山县栝蒌根结线虫发生危害及大田药效试验

为了有效防治栝蒌根结线虫，调查了安徽省潜山县栝蒌根结线虫及其发生，并分析了栝蒌根围土壤线虫的组成。通过线虫形态学鉴定，认为潜山栝蒌上的根结线虫为Meloidogyne incognita。栝萎根围土壤中有口针线虫占调查总量的50．7％，根结线虫2龄幼虫（J2）占31．8％。对当年栝萎J2在土壤表、中、下层的分布和年发生调查结果表明，J2在各层的分布量因月份不同而不同，并分别于3月初到9月中旬问出现2次虫口高峰；防治试验结果表明，除有机肥外，各试验小区在施药后49天J2虫口相对减退率在89．6％以上；施药后124天，克线丹和1．8％阿维菌素处理的小区增果率为250％～480％，收到很好的防效。     

Evaluation of alternative rice planthopper control by the combined action of oil-formulated Metarhizium anisopliae and low-rate buprofezin

BACKGROUND: High resistance of brown planthopper (BPH) Nilaparvata lugens Stål to common insecticides is a challenge for control of the pest. An alternative control strategy based on the combined application of fungal and chemical agents has been evaluated. RESULTS: Three gradient spore concentrations of oil‐formulated Metarhizium anisopliae (Metschnikoff) Sorokin (Ma456) were sprayed onto third‐instar nymphs in five bioassays comprising the low buprofezin rates of 0, 10, 20, 30 and 40 µg mL^?1 respectively. Fungal LC₅₀ after 1 week at 25 °C and 14:10 h light:dark photoperiod decreased from 386 conidia mm^?2 in the buprofezin‐free bioassay to 40 at the highest chemical rate. Buprofezin (LC₅₀: 1647, 486 and 233 µg mL^?1 on days 2 to 4) had no significant effect on the fungal outgrowths of mycosis‐killed cadavers at the low application rates. The fungal infection was found to cause 81% reduction in reproductive potential of BPH adults. In two 40 day field trials, significant planthopper (mainly BPH) control (54–60%) was achieved by biweekly sprays of two fungal candidates (Ma456 and Ma576) at 1.5 × 10¹³ conidia ha^?1 and elevated to 80–83% by incorporating 30.8 g buprofezin ha^?1 into the fungal sprays. CONCLUSION: The combined application of the fungal and chemical agents is a promising alternative strategy for BPH control. Copyright © 2010 Society of Chemical Industry     

无机化合物对南方根结线虫行为的影响

利用体外生物测定方法,研究常见无机化合物对南方根结线虫Meloidogyne incognita 2龄幼虫(J_2)存活、趋性以及卵囊内卵孵化的影响.结果表明,不同化合物不同浓度处理对M.incognita的影响差异显著.随着无机化合物浓度的增加,J_2死亡率上升,NH_4HCO_3、Na_2SO_4、CuCl_2·2H_2O、CuSO_4·5H_2O和FeCl_3·6H_2O浓度分别为O.03、0.03、0.0003、0.0004和0.0007 mol/L即可抑制其存活.除Cu~(2+)化合物外,其它无机化合物在供试浓度下均对卵囊内卵的孵化有明显抑制作用.含Ca~(2+)化合物均对南方根结线虫J_2有吸引作用,而含NH_4~+的NH_4HCO_3和NH_4NO_3对J_2排斥.除碳酸氢铵LC_(90)抑制种子萌发外,其它化合物对番茄种子萌发无抑制作用,但对后期幼根的伸长有抑制作用.盆栽试验结果显示,CuSO_4·5H_2O防治效果最佳,在LC_(50)处理下与对照相比防效可达70.8%.     

球孢白僵菌孢子萌发促进剂的筛选及其对杀蚜效果的增强作用

以生物学相容性较好的聚乙二醇辛基苯基醚为乳化剂,从五大类生化营养基质中筛选出海藻糖、葡萄糖、蛋白胨、酪氨酸和菜籽油作为孢子萌发促进剂的基本成份,采用5因子正交旋转组合设计并实施了36个组配试验以优化配方。将所获孢子萌发促进剂加入球孢白僵菌(Beauveria bassiana)孢子乳悬液中喷雾接种桃蚜(Myzus persicae)无翅成蚜,在20℃和12L:12D的条件下饲养并逐日观察发病死亡数。所获数据经时间-剂量-死亡率模型模拟分析,桃蚜接种后第4～6天为死亡高峰,在10~6～10~8个孢子/ml的浓度下喷雾处理6天后的累计死亡率为62.9％～88.7％,LT_(50)估计值为3.8～4.8天,接种后第4、5和6天的LD_(50)估计值分别为3.75×10~7、3.73×10~5和2.08×10~5个孢子/ml。在连续6天的观察中,接种成蚜日均产若蚜数比对照分别下降了40.7％～85.0％,下降幅度随孢子乳悬液浓度提高而增大。这些结果表明,以上孢子萌发促进剂具有作为球孢白僵菌孢子制剂添加剂的应用潜力。     

不同种子处理方法下长枝木霉T6菌株对小油菜促生作用及生理特性的影响

为了明确长枝木霉T6菌株(Trichoderma longibrachiatm)对小油菜(Brassica chinensis)促生效果及生理特性的影响，通过水琼脂培养法、浸泡法和灌根法进行种子处理，并测定了长枝木霉T6菌株及其孢子悬浮液和发酵滤液处理后小油菜种子活性、根系发育及幼苗叶绿素和可溶性蛋白含量的变化情况。结果表明：与对照相比，采用水琼脂培养法，接种长枝木霉T6菌株后小油菜种子发芽率、发芽指数、胚根长度、胚芽长度、幼苗鲜重和干重相对增长率分别为2.51%、20.55%、70.79%、21.98%、32.00%和30.00%,幼苗根系总投影面积、总根表面积、平均根系直径、总根体积和根尖数相对增长率分别为58.49%、58.79%、18.18%、100.00%和77.88%;采用种子浸泡法，浓度为1.0×10⁷ cfu·mL^-1长枝木霉T6菌株孢子悬浮液处理后显著提高了小油菜种子发芽率、发芽指数、胚根长度、胚芽长度、幼苗鲜重和干重，其相对增长率分别为2.06%、19.60%、82.21%、43.36%、31.58%和40.00%,根系总...     

Synergistic and antagonistic interactions of terpenes against Meloidogyne incognita and the nematicidal activity of essential oils from seven plants indigenous to Greece

BACKGROUND: Biorational means for phytonematode control were studied within the context of an increasingly ecofriendly pest management global approach. The nematicidal activity and the chemical composition of essential oils (EOs) isolated from seven plants grown in Greece and ten selected compounds extracted from them against second‐stage juveniles (J2) of Meloidogyne incognita (Kof. & White) Chitwood were evaluated using juvenile paralysis experiments. Additionally, synergistic and antagonistic interactions between nematicidal terpenes were studied using an effect addition model, with the comparison made at one concentration level. RESULTS: The 96 h EC₅₀ values of Foeniculum vulgare Mill., Pimpinella anisum L., Eucalyptus meliodora A Cunn ex Schauer and Pistacia terebinthus L. were 231, 269, 807 and 1116 µg mL^?1, respectively, in an immersion bioassay. Benzaldehyde (9 µg mL^?1) was the most toxic compound, followed by γ‐eudesmol (50 µg mL^?1) and estragole (180 µg mL^?1), based on 96 h EC₅₀ values. The most potent terpene pairs between which synergistic actions were found, in decreasing order, were: trans‐anethole/geraniol, trans‐anethole/eugenol, carvacrol/eugenol and geraniol/carvacrol. CONCLUSION: This is the first report on the activity of F. vulgare, P. anisum, E. meliodora and P. terebinthus, and additionally on synergistic/antagonistic nematicidal terpene interactions, against M. incognita, providing alternative methods for nematode control. Copyright © 2010 Society of Chemical Industry