保护地常用农药对蜡蚧轮枝菌菌丝生长影响研究

6种杀虫剂和 6种杀菌剂对昆虫病原真菌蜡蚧轮枝菌菌丝生长影响的研究结果表明 ,杀虫剂对蜡蚧轮枝菌菌丝生长有程度不同的抑制作用。在田间常规使用浓度下 ,5种杀虫剂对菌丝生长的抑制率在 10 %以上 ,最高者为甲氰菊酯达 17.6%。田间常规使用浓度稀释 10倍下 ,杀虫剂万灵、快灭净和锐劲特对菌丝生长抑制率低于 5% ,锐劲特在3.3～33.3mg/L时 ,菌丝生长与对照无显著差异 ,表现出与蜡蚧轮枝菌有极好的相容性 ,是菌药混用较好的候选杀虫剂。杀菌剂对蜡蚧轮枝菌菌丝生长有强烈的抑制作用 ,浓度愈高 ,抑制程度愈强。因此 ,在利用蜡蚧轮枝菌防治保护地蔬菜害虫时 ,须与杀菌剂使用保持一定的间隔期     

蜡蚧轮枝菌及其在生防中的应用

六十年代是利用微生物防治害虫迅速发展的时代。国内外对白僵菌、绿僵菌、苏云金杆菌等的理论研究和实际应用都做了大量工作。自1970年以来,许多国家开始了蜡蚧轮枝菌Verticillium lecanii的应用研究。英国温室作物研究所Hall对能寄生植物害虫(如蚜、蚧)和病菌(如锈菌、白粉菌)的蜡蚧轮枝菌的分类、生物学特性,毒力测定、与化学农药的配合使用、温室及田间应用等取得很大进展。印度Easwaramoorthy等也做了大量田间防治工作。现简介有关研究概况,供生防工作者参考。     

三种控制因子对湿地松粉蚧联合控制作用的模拟分析

利用虫生真菌蜡蚧轮枝菌、芽枝状枝孢霉和圆斑弯叶毛瓢虫对湿地松粉蚧的自然种群进行控制试验,在湿地松粉蚧自然种群连续生命表的基础上,通过以空间状态方程为分析手段,就圆斑弯叶毛瓢虫、芽枝状枝孢霉和蜡蚧轮枝菌对湿地松粉蚧联合作用进行了模拟分析,结果表明各种组合比较单独因子更能有效地控制湿地松粉蚧。     

蜡蚧菌防治小型害虫研究与应用进展

蜡蚧菌属(Lecanicillium)真菌是十分重要的昆虫病原真菌,具有致病性强、寄主范围广和对环境无污染等特点。国外已将多种蜡蚧菌开发成商品化制剂用于农林病虫害防治,而国内的开发应用相对较弱。为了更好地将蜡蚧菌应用于生物防治领域,本文综述了蜡蚧菌的分类地位及其应用于蚜虫、粉虱、蓟马和木虱等小型害虫防治的研究进展,并论述了目前存在的应用技术问题及解决途经,以期为开展相关生物防治的研究与应用提供参考。     

柑桔介壳虫的致病微生物

在柑桔园中,利用天敌防治柑桔蚧类被日益重视,作为柑桔介壳虫的一类天敌——致病微生物的研究渐趋深入。 常见的柑桔蚧类的致病微生物多为真菌类,最重要的为蜡蚧轮枝菌,该菌广泛分布于热带、亚热带和温带。锡兰、古巴、印尼、英、美、波、印等国都有报道,台湾亦早有(日本人)报道,大陆于1982年在贵州发现,以后在南方几个省市相继发现,说明在南方分布较广泛,北京也发现该菌流行(温室白粉虱上)。该菌可使多种柑桔介壳虫大量死亡,如柑桔软蜡蚧、红蜡蚧等,还可寄生褐圆蚧、矢尖蚧、长牡蛎蚧、黑点     

土壤蜡蚧轮枝菌DNA提取方法的改进及其应用效果

土壤真菌分子生态学研究需要大量和高效地提取真菌的DNA。应用市售的一般试剂盒提取土壤虫生真菌DNA,常常存在得率和质量低的问题,甚至根本提取不到土壤真菌的DNA样品。针对这一问题,本研究对细胞破碎方式及后续DNA提取参数进行了一系列的改进和优化,建立了一套针对性的提取方法。该提取法对虫生真菌—蜡蚧轮枝菌纯培养物的灵敏度极高,可在10个孢子的条件下提取到DNA,而市售的试剂盒则不能提取到(试剂盒在107个孢子条件仍提不到DNA);该提取法对人工投菌土样的DNA提取灵敏度达到102个孢子/克土,所得的DNA纯度高,无明显抑制后续PCR扩增的物质;施用过蜡蚧轮枝菌的田间土样所得DNA样品可成功扩增出蜡蚧轮枝菌特异片段,而未施用过蜡蚧轮枝菌的田间土样所得DNA样品不能扩增出蜡蚧轮枝菌特异片段。本提取方法具有灵敏度和纯度高的特点,适用于土壤虫生真菌的分子生态学样品制备。     

营养和农药对蜡蚧轮枝菌生长发育的影响

在25℃条件下,测定了4种培养基和8种农药对蜡蚧轮枝菌生长发育的影响。结果表明,马铃薯葡萄糖和查氏培养基最适于菌丝生长和产生分生孢子。所有供试农药对蜡蚧轮枝菌菌丝生长均有显著的抑制作用,其中代森锰锌的抑菌率高达100%,其次为代森锌、百菌清及敌敌畏,再次为氯氰菊酯和阿维柴油,链霉素和氟虫腈的抑菌率最低。     

北京温室白粉虱上蜡蚧轮枝菌的自然流行

蜡蚧轮枝菌Verticillium lecanii(Zimm)Viegas是一种分布极广的昆虫病原真菌,国外早有用于控制蚜虫和介壳虫的报道。近年,英国已生产Mycotal可湿性粉剂用于防治温室白粉虱。该菌自然大流行仅在热带和亚热带地区的常见寄主介壳虫、蚜虫上观察     

螺旋粉虱感染蜡蚧轮枝菌对其保护酶和解毒酶活性的影响

测定了螺旋粉虱3龄若虫在感染蜡蚧轮枝菌后几种保护酶和解毒酶的活性变化情况.结果表明,螺旋粉虱在感染蜡蚧轮枝菌后不同时间其体内保护酶和解毒酶的活性会产生一定程度的变化.螺旋粉虱的SOD、GST和EST比活力在感染36 h后达到最大值,显著高于同期对照组的比活力,分别为对照组的1.21、1.27倍和1.47倍;感染后36 h和48 h,CAT的比活力显著高于对照组的比活力;而感染后不同时间的POD及MFO比活力差异不显著,与对照组的比活力也无显著性差异.初步判断,螺旋粉虱感染蜡蚧轮枝菌后,其体内的防御机制与SOD、CAT、GST及EST活性有一定的相关性,与POD和MFO活性关联不大.     

蜡蚧轮枝菌对茶蚜的侵染动态

接种4株蜡蚧轮枝菌[Lecanicillium(Verticillium) lecanii]菌株V07、V08、V23和V27不同剂量(2×10~3、2×10~4、2×10~5、2×10~6和2×10~7孢子/ml)孢子悬浮液于茶蚜(Toxoptera aurantii)室内种群,观察茶蚜种群的感染流行情况,得到蜡蚧轮枝菌侵染茶蚜的发病指数。结果表明:相同初始接种剂量,菌株V07对烟粉虱的侵染速率最快;同一菌株侵染速率随初始接种孢子浓度的增大而增大。     

蜡蚧轮枝菌对月季长管蚜的毒力测定

研究结果表明蜡蚧轮枝菌对月季长管蚜有较强的致病性,孢子浓度2.0×105个/mL时可造成大量月季长管蚜感染死亡,其LT50=（6.62±0.14）d; 而高浓度2.0×108个/mL对月季长管蚜感染致死的LT50=（4.69±0.16）d,第8天的死亡率达93.6%,致死中时随浓度增加而缩短。第5天的致死中浓度为（1.72±0.18）×107个/mL,第8天为（1.53±0.15）×104个/mL,致死中浓度随时间增加而减小。     

应用虫生真菌防治烟粉虱的现状

发虱Bemisia tabaci属世界性分布的大害虫。在一定条件下虫生真菌是控制烟粉虱种群的最有效天。本文就几种常见虫生真菌：蜡蚧轮枝菌Vericillium lecanii、座壳孢Aschersonia spp.、玫烟色拟青霉Paecilomyces fumosoroseus、球孢白僵菌Beauveria bassiana等防治烟粉虱的应用现状以及它们与其它敌的关系进行了综述，以期对烟粉虱虫生真菌的合理利用提供参考。     

Laboratory evaluation of temperature effects on the germination and growth of entomopathogenic fungi and on their pathogenicity to two aphid species

As part of an approach to select potential mycoinsecticides for aphid biocontrol, we investigated the effects of temperature on the growth, germination and pathogenicity of some hyphomycete fungi. Commercially available mycoinsecticides (based on Beauveria bassiana (Balsamo) Vuillemin and Verticillium lecanii (Zimmermann) Viegas) and other isolates of B bassiana, V lecanii, Metarhizium anisopliae (Metschnikoff) Sorokin and Paecilomyces fumosoroseus (Wize) Brown & Smith were evaluated. The rate of in vitro conidial germination of all isolates was slower at 10 and 15 degrees C than at 20 and 25 degrees C. Similarly, in vitro growth of most isolates was adversely affected at 10 and 15 degrees C. The greatest reduction at 10 degrees C in rates of conidial germination and colony growth, compared with other temperatures, was for M anisopliae isolates. Germination of V lecanii (isolate HRI 1.72) was fastest at 10 degrees C compared with the other fungi. It was also the most pathogenic of three isolates tested against Aphis fabae Scopoli and Myzus persicae Sulzer at 10, 18 and 23 degrees C. Generally, A fabae was more susceptible than M persicae to infection by the fungal isolates tested. A significant interaction between aphid species and temperature indicated that the pathogenic nature of an isolate was dependent not only on the target aphid species but also the temperature conditions of the bioassay. The series of studies, detailed above, allowed a temperature profile to be formed for the different isolates. Verticillium lecanii isolate HRI 1.72 (commercialised as Vertalec) was the most promising isolate selected from results of the series of experiments. Temperature profiles in conjunction with infectivity assays can be useful in selecting appropriate isolates for a particular thermal environment.     

The use of entomogenous fungi for pest control and the role of toxins in pathogenesis

Fungi have been suggested as agents for the biological control of insects for over a century, but their use remains extremely limited. This paper examines the biology of entomogenous fungi, highlighting their need for moisture, and reviews studies on the Entomophthoraceae, Beauveria bassiana, Beauveria brongniartii, Metarhizium anisopliae and Verticillium lecanii. It is suggested that current studies should be directed towards the control of pests living in humid micro-climates and that moisture-retaining formulations should be developed to reduce the reliance of fungi on moisture. Many entomogenous fungi produce insecticidal toxins in submerged culture and these compounds are of interest as a source of new toxophores. The most extensively studied toxins are the cyclic depsipeptides from M. anisopliae, termed destruxins, and their possible role in pathogenesis is discussed. Beauveria bassiana also produces the cyclic peptides termed beauvericin, beauverolides, and bassianolide. Toxins produced by V. lecanii, and the Entomophthoraceae are also described.     

Ultrastructural and Cytochemical Investigations of the Antagonistic Effect of Verticillium lecanii on Cucumber Powdery Mildew

ABSTRACT Chronological events of the intercellular interaction between Verticillium lecanii and cucumber powdery mildew, caused by Sphaerotheca fuliginea, were investigated at different times after inoculation by transmission electron microscopy. V. lecanii hyphae colonized host structures by tight binding, apparently mediated by a thin mucilaginous matrix. As early as 24 h after application of the antagonist, increased vacuolation and disorganization of the cytoplasm of the pathogen hyphae were easily detected. By 36 h after treatment, plasmalemma retraction and local cytoplasm aggregation were typical features of damage. Labeling chitin with the wheat germ agglutinin (WGA)/ovomucoid-gold complex showed that intracellular invasion of S. fuliginea by V. lecanii did not cause extensive host cell wall alterations, except in the area of hyphal penetration. By 48 h after inoculation, further cytoplasm disorganization was observed, as evidenced by the loss of cell turgor and contortion of the cell wall. Such deformation suggests that penetration of the antagonist results from mechanical pressure or localized enzymatic hydrolysis through the action of chitinases, as confirmed by the pattern of labeling obtained with the WGA/ovomucoid-gold complex. By 72 h after contact between the fungi, S. fuliginea cells were markedly collapsed, depleted of their protoplasm due to extensive multiplication of the antagonist, and totally encircled by the antagonist. Based on the current observations, the antagonism of S. fuliginea by V. lecanii appears to involve the following events: (i) attachment of the antagonist to the powdery mildew fungus; (ii) mechanical pressure and production of cell-wall degrading enzymes such as chitinases; (iii) penetration and active growth of the antagonist inside the pathogen hyphae; and (iv) digestion of host tissues and release of the antagonist from dead cells of S. fuliginea. The interaction between V. lecanii and S. fuliginea also affected the morphological and structural features of the haustorial bodies, as shown by increased vacuolation, distortion, and necrotization of the haustorial lobes. These observations provide the first experimental evidence that V. lecanii, primarily known as an entomopathogenic fungus, also has the potential to colonize mycelial structures of S. fuliginea. V. lecanii, therefore, may become a valuable alternative to current management of cucumber powdery mildew in greenhouses.     

Evidence for Antibiosis and Induced Host Defense Reactions in the Interaction Between Verticillium lecanii and Penicillium digitatum, the Causal Agent of Green Mold

ABSTRACT Chronological events of the intercellular interaction between Verticillium lecanii and the postharvest pathogen Penicillium digitatum were investigated by transmission electron microscopy and gold cytochemistry. Growth inhibition of P. oligandrum as a response to V. lecanii attack correlated with striking host changes including retraction of the plasma membrane and cytoplasm disorganization. Such changes were associated with the deposition on the inner host cell surface of a chitin- and cellulose-enriched material which appeared to be laid down as a structural defense reaction. The accumulation of chitin in the newly formed material correlated with a decrease in the amount of wallbound chitin. However, the deposition of cellulose appeared to correspond to a de novo synthesis, as evidenced by the occurrence of cellulose-containing vesicles which released their content in the space between the invaginated plasma membrane and the host cell wall. Results of the present study provide the first ultrastructural and cytochemical evidence that antagonism, triggered by V. lecanii, is a multifaceted process in which antibiosis, with alteration of the host hyphae prior to contact with the antagonist, appears to be the key process in the antagonism against P. digitatum.     

蜡蚧轮枝菌固态发酵基质筛选和发酵条件研究

在对昆虫病原真菌-蜡蚧轮枝菌菌株Tri-BA81进行单一基质和一般组合基质固体发酵初步筛选的基础上,选取谷子、麦麸、磷酸盐和稻壳为4个组分因子,每个因子分别设有不同质量比例的3个水平,按正交设计(L_{93)进行优化组合筛选研究。同时,对影响该菌固体发酵产孢的几个因素进行了初步研究。结果表明,产孢量最高的正交组合为5号配方,分生孢子产量达1.7×10¹⁰个/g。该菌固态发酵的最适初始含水量为固体基质与水的比例为1∶0.6,最适pH为5.87。}