阿·苏WP对小菜蛾毒力测定及田间药效试验

室内毒力测定结果表明，阿·苏WP对小菜蛾有明显的增效作用，其共毒系数为150．1。大田试验结果表明，阿·苏WP1125－1500g·hm^-2药后3d对小菜蛾防效为66．3％－85．2％，药后7d达86．1％－95．6％。     

小菜蛾颗体病毒与苏云金杆菌混合悬浮剂防治小菜蛾的田间药效试验

田间药效结果表明，小菜蛾颗体病毒与苏云金杆菌混合悬浮对小菜蛾(Plutella xylostella L.)有较好的防治效果，药后5天，小菜蛾颗体病毒与苏云金杆菌混合悬浮剂高剂量组100ml／667m^2的防效为77．46％明显高于对照药剂高效Bt可湿性粉剂，药后7d防治效果仍达75．89％。该药剂对菜青虫具有一定的兼治作用，对天敌影响较少，田间药效表现较为迟缓，试验期间无药害现象发生。能降低化学农药的使用量，有助于延缓害虫抗药性的产生，减少对环境的影响，促进绿色食品的产生。田间使用防治小菜蛾时，以其商品量75．100ml／667m^2左右为宜。     

苏云金芽孢杆菌液剂与杀虫双混用对稻纵卷叶螟的增效作用

室内生物测定表明,Bt液剂和不同比例的25％杀虫双混用对稻纵卷叶螟都有不同程度的增效作用,其中3:1和1:1(Bt:杀虫双)混用增效作用最为明显,共毒系数分别为265和298。1:1混用的毒效为杀虫双单用的1.71倍。田间小区试验表明,1:1混用的防治效果接近于同剂量的杀虫双。     

阿·苏WP对小菜蛾毒力测定及田间药效试验

室内毒力测定结果表明 ,阿·苏 WP对小菜蛾有明显的增效作用 ,其共毒系数为 15 0 .1。大田试验结果表明 ,阿·苏 WP112 5～ 15 0 0 g· hm-2药后 3d对小菜蛾防效为 6 6 .3%～ 85 .2 % ,药后 7d达86 .1%～ 95 .6 %。     

小菜蛾抗性稳定性及抗性治理对策研究

试验表明，福州地区田间小菜蛾已对有机磷、氨基甲酸酯及拟除虫菊酯产 生高抗性。脱离选择压力3代后，小菜蛾的抗性水平迅速下降。Bt预处理可提高抗性和敏感小菜蛾幼虫 对有机磷的敏感性，尤其对抗性小菜蛾增效极显著，对敏感小菜蛾AChE的 Ki值则影响不 大。据此提出在抗性治理中，应轮用或换用不同毒理机制的杀虫剂，且其间隔至少为2～3代。     

氯虫苯甲酰胺、阿维菌素与苏云金芽胞杆菌桶混对不同地区抗性小菜蛾的防治效果

为了解云南通海、湖北武汉、海南海口田间小菜蛾种群对氯虫苯甲酰胺、阿维菌素、苏云金芽胞杆菌抗药性现状及其桶混的田间防治效果,为小菜蛾抗性治理策略提供参考,推进化学农药减量控害。采用叶片浸渍法和田间小区试验对以上3种杀虫剂进行抗药性测定和田间药效试验。结果表明,3个地区小菜蛾田间种群均对阿维菌素产生了高水平抗性,抗药性倍数为276.0~1062.0倍,对氯虫苯甲酰胺抗药性达到中等至高水平抗性,抗药性倍数为60.0~671.0倍,对苏云金芽胞杆菌表现为中等及以下水平抗性,抗药性倍数为5.1~15.2倍。田间防治效果和抗性水平呈现出一定的相关性,苏云金芽胞杆菌药后7 d均达到70%以上,而氯虫苯甲酰胺、阿维菌素单剂药后7 d防治效果均达不到60%。氯虫苯甲酰胺、阿维菌素和苏云金芽胞杆菌桶混处理的田间防治效果在以上地区分别为88.70%和81.50%,防治效果较好,桶混处理防效与各单剂相比差异极显著。因此,建议可以桶混、轮换使用苏云金芽胞杆菌,以提高对小菜蛾的持续控制效果。     

苏云金芽胞杆菌G033A对新发南美番茄潜叶蛾的室内毒力及田间防效

南美番茄潜叶蛾Tuta absoluta（Meyrick）是新近传入我国的一种世界毁灭性番茄害虫，对我国番茄产业的潜在威胁巨大。为有效控制南美番茄潜叶蛾，测定了新型苏云金芽胞杆菌基因工程菌G033A（Bt G033A）对该昆虫的室内毒力及田间防效。结果表明，在室内条件下，以32000 IU/mg Bt G033A WP处理过的番茄叶片饲喂南美番茄潜叶蛾幼虫，其室内毒力效果由高至底依次为4龄幼虫，3龄幼虫，1～2龄幼虫，致死中浓度LC₅₀分别为14.63、15.59和23.17 g/L；浓度在10 g/L及以上时，Bt G033A对南美番茄潜叶蛾各龄幼虫的毒力均较高，处理后96 h（第4 d）校正死亡率均超过90%。在田间条件下，以Bt G033A WP 100倍液（10 g/L）喷雾防治低龄幼虫即有较好的防效，药后第5 d对1龄和2龄幼虫的校正死亡率分别为89.1%和98.0%，药后第7 d对1龄和2龄幼虫的校正死亡率均为100%；并且，与常用的生物杀虫药剂鱼藤酮的防效相当。研究结果对有机蔬菜生产基地新发南美番茄潜叶蛾的有效控制及其综合防控方案制定，具有重要指导意义。     

茶毛虫核型多角体病毒和Bt混剂的配比筛选及药效评价

在室内条件下采用浸叶法测定了茶毛虫核型多角体病毒(Euproctis pseudoconspersa nucleopolyhedrovirus,EpNPV)和苏云金杆菌(Bacillus thuringiensis,Bt)及其不同配比对茶毛虫的毒力,结果表明,EpNPV和Bt 5种比例混用均表现出不同程度的增效作用,共毒系数在177.3~221.7之间。其中以1.0×104PIB/μL EpNPV+2 000IU/μL Bt混用增效最明显,其毒效是Bt单剂的2.54倍。田间小区试验表明,EpNPV-Bt混剂(1.0×104PIB/μL EpNPV+2 000IU/μLBt)对茶毛虫幼虫有优良的防效,显著优于Bt单剂和EpNPV单剂(p0.05)。     

苏云金芽胞杆菌在马铃薯甲虫防治上的研究进展

马铃薯甲虫是重要的入侵害虫,严重威胁着我国粮食作物马铃薯的生产。苏云金芽胞杆菌是重要的农业害虫生防细菌,对马铃薯甲虫有良好的防治效果。本文围绕苏云金芽胞杆菌在马铃薯甲虫防治上的研究进展与应用进行综述。主要从马铃薯甲虫的入侵与防治手段、苏云金芽胞杆菌的晶体蛋白结构与杀虫机制、对马铃薯甲虫有活性的Bt毒蛋白研究进展、Bt毒蛋白对马铃薯甲虫的作用机制以及马铃薯甲虫对Bt毒蛋白的抗性机制等方面进行了综述。最后,从Bt新基因的挖掘和杀虫机理方面对苏云金芽胞杆菌在马铃薯甲虫防治上的研究进行了展望。     

苏云金芽胞杆菌分离过程中无晶体芽胞杆菌的分析

本研究选择了在苏云金芽胞杆菌Bacillus thuringiensis(Bt)分离过程中发现的与Bt芽胞相似、没有伴胞晶体的8株芽胞杆菌,对其种属、质粒等生物学特性和杀虫活性进行了初步研究.对分离菌株所产芽胞进行形态观察及质粒图谱分析,发现其与Bt相似;但肽指纹图谱分析和16S rDNA聚类研究表明所分离菌株与蜡样芽胞杆菌B.cereus(Bc)匹配最高;杀虫活性测定表明这8株菌对猿叶甲Colaphellus bowringi幼虫均无毒杀作用,而15-3、W23-1和W25-3 3个菌株及其培养上清液对小菜蛾Plutella xylostella幼虫有一定的杀虫活性,说明它们能产生活性物质.这些结果说明在Bt菌株的分离过程中要对无晶体菌株加以重视,其含有的活性物质具有潜在的研究和利用价值.     

四株虫生真菌的鉴定及其对小菜蛾的室内毒力

为了明确4株虫生真菌在小菜蛾防治中的应用潜力,采用生物测定法测定其室内毒力,并通过多相分类法研究其分类地位。结果表明:菌株GZU-BCECWC113对小菜蛾的毒力最强,在1.6×108孢子/mL浓度下对小菜蛾的校正死亡率最高,达到89.47%;半致死时间LT50值最小,为3.33天;感染8天时的LC50值最小,为0.45×105孢子/mL。根据形态特征、培养性状及ITS序列分析结果明确4株菌的分类地位,即GZU-BCECWC113为环链拟青霉Paecilomyces catenianulatus,GZU-BCECWQ16为玫烟色拟青霉P.fumosorosenus,GZU-BCECW122为蝉拟青霉P.cicadae,GZU-BCEC-WKKS2为细脚拟青霉P.tenuipes。     

Synthesis and insecticidal activities of novel derivatives of podophyllotoxin: Part XII

In order to find the biorational pesticides, eight novel 4β-substituted phenoxyaniline derivatives of podophyllotoxin have been synthesized with significant stereoselectivity and improved yields by employing the BF₃·Et₂O/NaI reagent system and evaluated for their antifeedant effect against 5th instar larvae of Pieris rapae and effect on the development of 5th instar larvae of P. rapae as well as for insecticidal activity against P. rapae. The antifeedant activities showed that these compounds exhibited less potent than podophyllotoxin. Though these derivatives showed less potent antifeedant activities than podophyllotoxin, they acted as growth development inhibitor to 5th instar larvae of P. rapae, which were found that the animals treated with podophyllotoxin and its derivatives showed moulting disturbances and/or deformities. Also, the insecticidal activity results show that all of these derivatives of PPT showed delayed insecticidal activity, which differs from traditional neurotoxic insecticides. Among them, compounds possessing a 4β-phenoxyaniline moiety substituted (CO₂C₂H₅, Cl and OH) at para position exhibited greater insecticidal activity against P. rapae than podophyllotoxin.     

苏云金杆菌亚致死浓度对美国白蛾及其寄生蜂生长发育的影响

为阐明苏云金杆菌Bacillus thuringiensis(Bt)与白蛾周氏啮小蜂Chouioia cunea Yang的协同作用,分别用103~108孢子/m L的6个Bt浓度处理美国白蛾Hyphantria cunea 2龄幼虫后,通过室内试验测定了Bt对其致死、亚致死效应,及亚致死浓度Bt对寄生蜂子代出蜂的影响。结果表明,浓度106孢子/m L处理组美国白蛾均未能化蛹;而106孢子/m L处理组均能化蛹并羽化,且幼虫发育历期随Bt浓度的增加而延长,平均蛹重在74.92~92.18 mg之间,均高于对照的68.66 mg,但蛹重不呈线性规律变化。当Bt对美国白蛾平均校正死亡率低于17.17%时,幼虫发育历期延迟不明显,但平均蛹重为101.11~124.34 mg,均高于对照;接蜂后能够正常出蜂,出蜂率为33.13%~51.25%,每蛹出蜂量为117.43~143.42头,均显著高于对照。表明用平均校正死亡率低于20%的Bt处理对白蛾周氏啮小蜂的寄生有利,2种生防措施协同作用存在增效潜力。     

A diagnostic medium for the semi-selective isolation and enumeration of <Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis>pv. <Emphasis Type="Italic">vignicola</Emphasis>

A semi-selective medium for isolation of Xanthomonas axonopodis pv. vignicola from cowpea (Vigna unguiculata) plant and soil samples was developed. Twelve carbon and five nitrogen sources were tested with four strains of X. axonopodispv.vignicola, and 25 antibiotics were screened against saprophytes. -cellobiose (10g) was selected as the optimal carbon source. Among the antibiotics, cefazoline inhibited growth of most of the saprophytes with little effect on strains of the pathogen. ,-methionine enhanced growth of X. axonopodispv.vignicola. Boric acid along with ammonium chloride suppressed growth of Pseudomonas fluorescens. The semi-selective medium designated as cefazoline-cellobiose-methionine (CCM) medium contained K₂HPO₄ 1.34g, KH₂PO₄ 0.4g, MgSO₄ 0.3g, H₃BO₃ 0.2g, NH₄Cl 1.0g, -cellobiose 10g, cycloheximide 0.2g, ,-methionine 1.0g, cefazoline 10mg and agar 14g per l of water (pH 7.2). Colonies of X. axonopodispv.vignicola on CCM medium were whitish, round, raised and 0.2–1.8mm in diameter 96h after incubation. CCM medium generally inhibited growth of Pantoea agglomerans, Bacillus subtilis and saprophytes isolated from cowpea leaves. Colonies of Pseudomonas fluorescens and a saprophytic bacterium, which were not completely suppressed by CCM, could be differentiated from X. axonopodispv.vignicola by their smaller size and different color. The CCM medium proved useful for isolation of X. axonopodispv.vignicola from cowpea plant and soil samples. This is the first report of a semi-selective medium developed for detection of X. axonopodispv.vignicola.     

Effects of triazophos on biochemical substances of transgenic Bt rice and its nontarget pest Nilaparvata lugens Stål under elevated CO2

The brown planthopper (BPH), Nilaparvata lugens Stål, is a serious rice pest throughout Asia. Recent outbreaks of N. lugens populations were mainly associated with the overuse of pesticides and resistance to insecticides. Warmer global temperatures that are associated with anthropogenic climate change are likely to have marked ecological effects on terrestrial ecosystems. However, the effects of elevated CO₂ concentrations on the biochemical, physiological and nutrient quality of transgenic Bt rice that has been treated with pesticides and on the control efficacy of the pesticides are not understood. The present study investigated changes in soluble sugar content, free amino acid levels, oxalic acid levels, flavonoids levels, and triazophos residues in transgenic Bt rice (TT51) and the control efficacy of triazophos for N. lugens following triazophos foliar spray under conditions of elevated CO₂ (eCO₂). Our findings showed that the soluble sugar content of TT51 treated with triazophos under eCO₂ was significantly higher than that under ambient CO₂ (aCO₂) and also higher than that of the non-transgenic parent (MH63) under aCO₂. However, the results for free amino acid levels were the opposite of those for soluble sugar levels. The oxalic acid and flavonoid contents of rice plants significantly decreased with increases in triazophos concentration, CO₂ concentration, and days after treatment (DAT). The oxalic acid and flavonoid contents of TT51 treated with triazophos under eCO₂ were significantly lower than those under aCO₂ and also lower than those of MH63 under aCO₂. The residue concentration of triazophos varied with CO₂ concentration, rice variety, and DAT. The residues in TT51 treated with 80 ppm of trizaopos under eCO₂ were significantly lower than those under aCO₂ and those in MH63 under aCO₂. The survival rate of nymphs N. lugens in TT51 under eCO₂ was significantly higher than that under aCO₂ and that in MH63 under aCO₂ at 1 DAT or 15 DAT after the release of 2nd instars nymphs. These findings indicated that (1) for TT51, triazophos reduced the resistance of rice plants to N. lugens with an elevated CO₂ concentration, as N. lugens consumed more phloem sap on TT51 plants; (2) triazophos dissipation in TT51 under eCO₂ was significantly faster than that under aCO₂ and that in MH63 under aCO₂; (3) the control efficacy of triazophos for N. lugens significantly decreased under eCO₂. The present findings provide important information for integrated pest management among transgenic varieties.     

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%.     

三种杀菌剂对玉米褐斑病菌的毒力及田间控制作用

采用孢子萌发法,分别测定了代森锰锌、戊唑醇和噁霉灵对玉米褐斑病菌Physoderma maydis的室内毒力;并通过田间小区试验,研究了80%代森锰锌可湿性粉剂(WP)、430 g/L戊唑醇悬浮剂(SC)和70%噁霉灵可湿性粉剂(WP)对病原菌致病力的影响,以及在8叶期茎叶喷雾处理对该病害的田间控制作用。结果表明:代森锰锌对病原菌休眠孢子囊的萌发具有明显的抑制作用,EC50值为66.71 mg/L,而戊唑醇和噁霉灵的抑制效果较差;代森锰锌和戊唑醇能有效降低病原菌的致病力,处理小区植株发病叶片均控制在穗位叶以下,且穗位叶叶绿素含量、净光合速率和根系活力均明显高于对照区,防效分别达91.31%和88.99%;代森锰锌和戊唑醇处理小区玉米增产效果明显,增产率分别达13.8%和11.5%。     

不同基质传代白僵菌对桑天牛幼虫的侵染力与寄主血淋巴酚氧化酶活性的关系

以诱集自土壤中、对桑天牛Apriona germari幼虫具有较高致病性的球孢白僵菌Beauveria bassiana Bb00为出发菌株R0,经反复接种桑天牛幼虫分别获得菌株R1、R2、R3和R4,而通过反复在普通查氏培养基上传代分别获得菌株M1、M2、M3和M4。分别用R0、R2、R4和M2、M4接种桑天牛幼虫,发现在普通培养基上传代会导致菌株致病力降低,而通过桑天牛幼虫传代培养可提高菌株的致病力。桑天牛幼虫感染白僵菌后,其免疫互作使酚氧化酶活性先迅速上升,随后因菌株的适应性增强而开始下降。用菌株M2、M4接种桑天牛幼虫后,其血淋巴酚氧化酶活性比接种R2和R4的高。各菌株引起的桑天牛幼虫酚氧化酶活性出现高峰值的时间与其LT50值具有一定的相关性,反映了各菌株不同的侵染速度;同时各菌株引起的酚氧化酶活性高峰值也与其LC50值高度相关。说明桑天牛幼虫血淋巴中酚氧化酶活性与不同菌株对桑天牛幼虫的毒力具有一定的相关性,同时酚氧化酶活性也可作为反映菌株毒力的一个重要参考指标。     

Isolation and partial characterization of an antifungal protein from the endophytic Bacillus subtilis strain EDR4

An antifungal protein E2, from the culture filtrate of the endophytic Bacillus subtilis strain EDR4 of wheat with a high activity against numerous fungal species in vitro and take-all in wheat caused by Gaeumannomyces graminis var. tritici in vivo, was purified by (NH₄)₂SO₄ precipitation, hydrophobic-interaction chromatography, anion-exchange chromatography and polyacrylamide gel electrophoresis (PAGE). The molecular mass of the protein was about 377.0 kDa determined by gel permeation chromatography (GPC) using a Superdex 200 10/300 GL pre-packed column and the pI value of the protein detected by isoelectric focusing PAGE was 6.59. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) the antifungal protein showed a band with a molecular mass of 39.1 kDa, which suggest that the native protein consists of multi-subunits. The amino acid sequences of three peptides from the antifungal protein were obtained by using a nano-ESI-MS/MS (Q-TOF2) System. The protein isolated may be regarded as a new protein according to amino acid sequences of three peptides. The purified protein exhibited inhibitory activity on mycelium growth of e.g. Fusarium graminearum, Macrophoma kuwatsukai, Rhizoctonia cerealis, Fusarium oxysporum f.sp. vasinfectum, Botrytis cinerea and G. graminis var. tritici (Ggt). Scanning electron microscopy showed that hyphae of Ggt treated with the antifungal protein were severely deformed. The antifungal protein E2 exhibited ribonuclease and hemagglutinating activities as well as a trifle protease activity. However, no β-1,3-glucanase, β-1,4-glucanase, chitinase or protease inhibitory activities were detected.     

Interaction of Cry1Ac toxin (Bacillus thuringiensis) and proteinase inhibitors on the growth, development, and midgut proteinase activities of the bollworm, Helicoverpa zea

Potential resistance development to Bt cotton in certain lepidopterans has prompted research to develop strategies that will preserve this environmental-friendly biotechnology. Proteinase inhibitors are potential candidates for enhancing Bt toxicity against lepidopteran pests and for expanding the spectrum of control for other insects. Interactions of Bt toxin from Bacillus thuringiensis and proteinase inhibitors were investigated by monitoring growth, development, and gut proteinase activities of the bollworm, Helicoverpa zea. Several proteinase inhibitors were combined with Bt protoxin Cry1Ac in artificial diet and fed to newly molted 3rd-instar bollworm larvae to determine effects on larval body weight and length, pupation progress, and mortality rate. Major midgut proteinase activities, including caseinase, tryptic, and chymotrypsin activities, were examined after treatment. A concentration of Bt at a level causing minimal mortality (<10%), was mixed with the following proteinase inhibitors: benzamidine, phenylmethylsulfonyl fluoride (PMSF), and N-α-tosyl-l-lysine chloromethyl ketone (TLCK). When compared with controls, the synergistic effect of Bt toxin and proteinase inhibitors caused significant decreases in mean larval weight and length over time. Midgut samples tested against the substrates azocasein, α-benzoyl-dl-arginine-p-nitroanilide (BApNA), and N-succinyl-alanine-alanine-proline-phenylalanine-p-nitroanilide (SAAPFpNA) showed significant decreases in the protease activity of larvae fed Bt plus inhibitor versus control. Interaction of Bt and proteinase inhibitors significantly retarded larval growth and resulted in developmental delay and up to 20% mortality.