球孢白僵菌对温室蚜虫的侵染生物学

研究了球孢白僵菌在不同浓度、施菌方式、温度和相对湿度下对温室蚜虫的侵染力以及接种后对蚜虫的侵染速率。结果表明,高(109个孢子.mL-1)、中(108个孢子.mL-1)、低(107个孢子.mL-1)3个浓度剂量对蚜虫都有较强的致病力,且浓度越大,蚜虫的死亡率越高,死亡时间越提前。用浸渍法和孢子浴法接种蚜虫,6 d的累积死亡率分别为100%和31.1%。在测试的3个温度(22、26、30℃)中,26℃时蚜虫侵染力最强,第3天出现死亡高峰,第5天时累积死亡率就达到100%,明显高于22、30℃的处理。相对湿度越大,球孢白僵菌的致病力越强,蚜虫死亡速度越快。在温湿度组合中相对湿度为95%时,温度对白僵菌的侵染力几乎无影响,但影响发病速度,相对湿度低于95%时,26℃的侵染力始终高于22和30℃时的侵染力。通过接种后不同时间段用0.2%百菌清处理蚜虫测定该菌株的侵染速率,结果表明接种后24 h是该球孢白僵菌有效侵染蚜虫的关键时期。     

球孢白僵菌对大豆蚜毒力的室内生物学测定

对来源于吉林省不同地区的15株球孢白僵菌Beauveria bassiana(Bals.)Vuill.菌种对大豆蚜Aphis glycines Matsumura毒力进行了室内生物学测定。所有供试菌株对大豆蚜虫均有一定的致病性,杀虫效率差异明显,杀虫效率与孢子浓度和作用时间均呈正相关。通过对大豆蚜毒力室内生物学测定结果的综合分析,菌株S14-X-1为毒力较高菌株,具有进一步研究应用价值。     

球孢白僵菌固态罐发酵产孢培养的研究

建立了一套两升圆柱体玻璃发酵罐的固态通风培养装置及通风系统。以球孢白僵菌Bb371为生产菌,培养基220g(82％麸皮 4．5％黄豆粉 4．5％玉米粉 9％稻壳)作为生产原料,接种30ml,23℃培养温度下,分阶段调节通风量和空气湿度,培养5d,产孢量可达到116亿／g干培养基。     

利用RAPD-PCR检测三种白僵菌及球孢白僵菌种内变异

采用PCR-RAPD技术研究了球孢白僵菌2株野生型多孢株及其各1株单孢分离株的 RAPD扩增片段的多态性,比较了彼此间的相似率。结果显示,相似率在63.6～99.3％之间变化很大,表明各分离子间的基因组DNA已发生变化。球孢白僵菌与另一种白僵菌布氏白僵菌之间的相似率在64.9％～80.9％之间,与粘孢白僵菌之间的相似率在50.0～61.9％之间。     

球孢白僵菌对壳聚糖降解作用的研究

在含有1%壳聚糖的培养基中,接种球孢白僵菌017菌株,25℃,200r/min振荡培养3天后,壳聚糖发生剧烈的降解作用,培养至第7天时,培养基的增比粘度(ηa.s)由7.07下降至0.76。粘度稀释法测定壳聚糖的粘均分子量(Mv)由3.5×10⁵下降至8.8×10⁴,剩余的可溶性氨基糖含量为345μg/ml。Sephadex G-200凝胶层析证明,壳聚糖被球孢自僵菌降解后存在着主要的均一组分。培养基中添加KNO₃,牛肉膏、N-乙酰氨基葡萄     

球孢白僵菌数量性状的典型相关分析

来源不同的球孢白例僵菌株的生物学性状（培养特征、产孢量、菌落生长速率及孢子萌发中时）、生态学性状（毒力、水分活性、紫外照射活率、水浴活率）及生物化学性状（草酸水平、蛋白酶产量、几丁质酶产量、葡萄糖苷酶产量、酯酶及脂肪酶产量）经观察测定,共得到１５个指标。对不同性状圾其组合进行典相关分析,结果表明生物学性状与生态学性状的相关主要为产一与菌株毒力及孢子水浴活率之间的相关生物学与生物化学性状间的相关主要     

草菇VvLaeA调控球孢白僵菌的生长发育

食用真菌草菇[Volvariella volvacea(Bull.ex.Fr.)Sing.]VvLaeA在调控真菌发育方面的功能并不清楚。本研究在对草菇VvLaeA进行生物信息学分析基础上,通过聚合酶链式反应(polymerase chain reaction,PCR)的方法将超量表达启动子Vvgpd和草菇VvlaeA基因的开放阅读框(open reading frame,ORF)进行融合,并将融合片段克隆入pK2(bar)载体。采用农杆菌介导的转化方法将重组载体pK2(bar)-OEVvlaeA转入球孢白僵菌中进行表达,测定转化子的菌株发育情况。结果表明,草菇VvLaeA与其他真菌的蛋白同源性较低;和野生型相比,转化菌株的菌落直径显著增大,色素减少,分生孢子产量和萌发率均显著下降,对胁迫反应的敏感性增强。进一步研究发现,转化菌株分生孢子的细胞壁结构成分发生改变,和分生孢子发育相关基因的表达被显著下调。提示草菇VvLaeA能提高球孢白僵菌菌株的生长速率,而负调控色素沉积和分生孢子发育,这为草菇基因功能鉴定提供了启示。     

The occurrence of nucleopolyhedrovirus infecting Hyposidra talaca (Geometridae: Lepidoptera), a tea defoliator from North-East India

We identified the nucleopolyhedrovirus (HytaNPV), specific to Hyposidra talaca, a major defoliator of tea in India by partial amplification of polyhedrin gene. The sequence analysis revealed HytaNPV is closely related to NPVs that infect Buzura suppressaria and Ectropis obliqua, in China.     

应用球孢白僵菌防治马尾松毛虫的策略及其生物多样性基础的研究

对３种不同方式应用球孢白僵菌防治马尾松毛虫的结果表明,３个林场的虫口在连续４年内均被抑制在低水平,但松毛虫种群动态不同：以淹没式施放白僵菌为主,但有时也淹没式施放化学杀虫剂的麻姑山林场平均虫口密度为３．１６±４．９４条·株－１,波动最大;长期接种式应用白僵菌的戴公山林场平均虫口密度只有０．０９±０．１４条·株－１,一直处于低密度状态;以化学农药处理小面积虫源地结合不频繁地淹没式施放白僵菌的金寺山林场平均虫口密度为１．４５±２．２９条·株－１,偶可达防治指标．对群落组成的调查结果表明,从麻姑山、金寺山到戴公山,动物和虫生真菌群落各物种的总个体数递减,而总物种数、总物种数与总个体数的比值,天敌与害虫种数和个体数的比值以及群落多样性指数皆递增,表明群落多样性渐趋丰富,食物链网渐趋复杂,群落稳定性和对害虫的自然控制能力逐渐增强．对群落动态的主成分分析进一步表明,从麻姑山、金寺山到戴公山,动物和虫生真菌群落的演化时序分明,趋于稳定,自我调节力强．     

白僵菌对茶小绿叶蝉田间防效的关键影响因素研究

白僵菌孢子萌发率和萌发速度是影响其田间防效的关键因素。通过对球孢白僵菌YP9(CCTCC No:M209238)孢子萌发的关键影响因素进行研究,得到以下田间应用条件:营养物质为2%麸皮浸出液(自然pH);孢子悬浮液喷洒浓度为5×10~7孢子/mL;在气温为23℃~28℃时喷洒。经昆明和无锡两试验地田间防效验证,该白僵菌在上述条件下对茶小绿叶蝉的田间防效高达65%,与茶农常用化学农药——天王星防效相当。     

有效积温法预测茶尺蠖防治适期的研究

利用22年历史气象资料和有效积温法,由茶尺蠖幼虫期或成虫发生高峰期预测下一代防治适期,并进行验证。1993年在室内外经5代39次预测验证,总符合率达96．6％。由幼虫期预测可使预报提前20～35天。     

Effect of culture substrates on virulence of Beauveria bassiana (Ascomycota: Cordycipitaceae) conidia against the browntail moth,Euproctis chrysorrhoea (Lepidoptera: Lymantriidae)

We studied the effect of different solid substrates on virulence of two Beauveria bassiana isolates against the browntail moth, Euproctis chrysorrhoea (L.) (Lep.: Lymantriidae). Conidia produced on wheat grains, wheat flour, wheat bran, rice flour, rice bran, rice paddy, corn flour, millet, and Sabouraud's dextrose agar with 1% yeast extract (SDAY) as control were compared. There were significant differences among these substrates for their effects on the virulence of produced conidia. Applying 10⁷ conidia/mL of B. bassiana EUT105, produced on rice bran caused the highest (84.9%) and on rice flour, the lowest (57.6%) mortalities. Bioassay on fifth-instar larvae using aerial conidia harvested from wheat grains, rice paddy, and SDAY indicated that conidia from wheat grains had the highest virulence while those from rice paddy, the lowest.     

球孢白僵菌九个菌株对赤拟谷盗成虫的毒效

球孢白僵菌Beauveria bassiana (Balsamo) Vuillemin是最重要的昆虫病原真菌,广泛用于防治世界各地的多种害虫.本研究评价了球孢白僵菌9个菌株对赤拟谷盗Tribolium castaneum (Herbst)成虫的致病性.将15头赤拟谷盗成虫浸入到4个浓度(1×106,l×107,l×lo8和l×109个分生孢子/mL)的白僵菌菌株中20 s,14 d内每日记录成虫的死亡率.结果表明:IRAN 440C菌株对赤拟谷盗成虫的LC50最低(5.04 ×l07个分生孢子/mL),IRAN187C菌株的最高(5.05 ×lo8个分生孢子/mL);DEBI 005菌株对赤拟谷盗成虫的LT5o最短(2.88 d),DEBI 014菌株的最长(4.96 d).根据LC50,LT50和死亡率结果得出IRAN 440C是防治这一害虫的理想菌株.     

Laboratory and field evaluation of Beauveria bassiana bait against two cockroach species (Dictyoptera: Blattellidae,Blattidae) in Jinan City,East China

A Beauveria bassiana bait formulation was evaluated for its efficacy in the laboratory and field against German cockroaches, Blattella germanica (L.), and American cockroaches, Periplaneta americana (L.). The LT₅₀ values were 46 and 119?h, respectively, for B. germanica and P. americana. The cockroach species were lured and killed effectively when linear distance was about 5?m between B. bassiana bait and fresh mouse food. In the field, more than 90% relative decline in density was found 14?d after treatment, which lasted for 90?d. In conclusion, laboratory and field studies demonstrated the high efficacy of a B. bassiana bait formulation against common cockroach species.     

Bioassay method for assessing the virulence of Beauveria bassiana against tarnished plant bug, Lygus lineolaris (Hem., Miridae)

A standard bioassay method for assessing the pathogenicity of Beauveria bassiana (Balsamo) Vuillemin (GHA strain) against second instar tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hem., Miridae) was developed. Several types of inoculation methods, assay containers and incubation times were tested. Our goal was to minimize control mortality and maximize treatment mortality. Five inoculation methods (immersing broccoli florets or bean pods, spraying broccoli florets or bean pods, and immersing insects) and four types of plastic containers (114‐, 171‐, 228‐ and 455‐ml) were tested. Immersing insects directly in a fungal suspension was the most effective inoculation method, which resulted in a treatment mortality of 70–81.3% at a concentration of 1 × 10⁷ conidia/ml. The 114‐ml plastic container was the most suitable assay container when 10 tarnished plant bug nymphs were treated together, resulting in a control mortality of only 6% 12 days after treatment. Within the first 6 days after treatment, 71.1% of the insects were killed, compared with a total mortality of 81.3% after 12 days. Nymphs infected with the test fungus changed colour from green to black. Mycelial outgrowth and sporulation on the cadavers demonstrated that most nymphs died of fungal infection. A total of 61.1 and 80.5% of the cadavers showed signs of mycelial outgrowth 9 days after death among those that were surface sterilized and those that were not, respectively.     

球孢白僵菌不同分离株对西花蓟马的毒力测定

【背景】西花蓟马是我国重要的一种入侵性害虫,已对多种化学农药产生了抗性。【方法】采用孢子悬浮液喷雾处理生测法,研究了8个球孢白僵菌菌株BbKM030716、BbCG051229、BbJS080625、BbQJ031121、BbXW060615、BbSM090521、BbYY090613和BbMZ051230对西花蓟马成虫的毒力,并用＂时间—剂量—死亡率＂模型进行了分析。【结果】供试球孢白僵菌各菌株对西花蓟马成虫侵染致病的剂量效应参数值分别为1.43、0.87、0.93、0.98、1.23、0.92、1.07和0.86。用1.25×104～1.25×108个·mL-1孢子悬浮液接种后,连续10d内西花蓟马的校正死亡率分别为44.13%～98.49%、12.63%～78.90%、30.36%～96.92%、51.36%～98.74%、26.14%～98.59%、7.27%～78.71%、49.06%～98.74%和27.67%～87.36%。球孢白僵菌对西花蓟马成虫的致死剂量是时间的函数,各菌株对西花蓟马成虫的致死中时随孢子浓度的增大而逐渐减小。【结论与意义】球孢白僵菌菌株BbKM030716、BbJS080625、BbQJ031121和BbXW060615对西花蓟马成虫具有较强毒力,可作为西花蓟马生防制剂开发的潜力菌株。     

Biocontrol of almond bark beetle (Scolytus amygdali Geurin-Meneville, Coleoptera: Scolytidae) using Beauveria bassiana (Bals.) Vuill. (Deuteromycotina: Hyphomycetes)

AIMS: To formulate the entomopathogenic fungus Beauveria bassiana in invert emulsion, then apply it against adults of almond bark beetle (Scolytus amygdali) under laboratory and field conditions. METHODS AND RESULTS: The effect of formulated B. bassiana in invert emulsion against S. amygdali adults was shown by comparing the mortality percentage of adults exposed to the formulated fungus using a Petri dish treatment method and by field applications to infested peach trees with mortality of adults exposed to the unformulated fungus or the untreated control. Results obtained from both exposure methods have indicated that treatment of S. amygdali adults with the formulated fungus resulted in a significantly higher mean mortality percentage (P < 0.05) when compared with the treatment with the unformulated fungus or the untreated control. This mortality ranged from 81.2 to 100%, 10 days after treatment with the formulated fungus when compared with 6.7 to 49.6% mortality, 10 days after treatment with the control or the unformulated fungus, respectively. Viability of the fungus conidia in invert emulsion was assessed by calculating the germination percentage of the conidia over time. Results indicated a high storage stability shown by a small loss of germination percentage for the formulated conidia of both strains (5.8 to 8.4% over a 12-week period) vs a low storage stability shown by a high loss of germination percentage for the unformulated conidia of the same strains (58.9 to 61.0% over the same period). The presence of B. bassiana in the galleries of beetles following the treatment of infested trees was shown in the present research. CONCLUSIONS: The results obtained have demonstrated a significantly higher level of efficacy of formulated B. bassiana in invert emulsion against S. amygdali adults under laboratory and field conditions. The ingredients of invert emulsion used in the formulation of the fungus had a negligible effect on the viability of formulated conidia when compared with the unformulated. SIGNIFICANCE AND IMPACT OF THE STUDY: Results obtained in the present research are promising and may be exploited commercially to control S. amygdali adults on various species of stone fruit trees, especially peach trees. This type of biocontrol of this insect may be used as an alternative means to chemical control for management of the insect. No adverse environmental impacts of the fungus or its formulation have been observed during application.