两种杀虫真菌制剂对茶小绿叶蝉的田间防效评价

于2002年盛夏在浙江遂昌一高山茶园对茶小绿叶蝉(Empoasca spp．)进行了真菌杀虫剂的田间药效试验。所用菌剂为球孢白僵菌(Beauveria bassiana)和玫烟色拟青霉(Paecilomyces fumosoroseus)的纯孢子悬乳剂及其与3％吡虫啉10％可湿剂的混配剂．各菌剂稀释500倍喷雾2次,间隔12d．结果表明。两种真菌的混配剂明显优于纯菌剂,其中球孢白僵菌混配剂的最高防效达83．4％,而玫烟色拟青霉的最高防效为71．3％．根据25d期间历次调查结果计算平均防效,球孢白僵菌混配剂达66．8％,玫烟色拟青霉混配剂为62．1％,含微量吡虫啉的矿物油为50．3％,球孢白僵菌和玫烟色拟青霉的纯菌剂分别为49．5％和19．0％,结合试验期间气候及田间种群结构特征,讨论了各处理问差异的来源及提高真菌杀虫剂控制茶小绿叶蝉效果的可能途径。     

应用虫生真菌防治烟粉虱的现状

烟粉虱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敌.本文就几种常见虫生真菌:蜡蚧轮枝菌Verticilliumlecanii、座壳孢Aschersoniaspp.、玫烟色拟青霉Paecilomycesfumosoroseus、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天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.     

玫烟色拟青霉和吡虫啉对烟粉虱种群的联合控制作用

利用生命表技术评价了在网室条件下玫烟色拟青霉和吡虫啉对烟粉虱种群的控制作用。在0·3%吡虫啉 1×106分生孢子/ml、0·1%吡虫啉 1×106分生孢子/ml、10%吡虫啉、1·0×106个孢子/ml菌液、1·0×106个孢子/ml菌液连续施用2次等5个不同的处理区,玫烟色拟青霉对第一代和第二代烟粉虱的种群干扰作用控制指数(IIPC)分别为0·5476、0·6836、0·3123、0·7278、0·4959和0·1566、0·1625、0·9830、0·2532、0·1349。其中,以使用0·3%吡虫啉 1·0×106分生孢子/ml处理区对烟粉虱种群的控制效果最好。玫烟色拟青霉与低浓度的吡虫啉混合使用能较好地发挥联合控制作用,对玫烟色拟青霉的累积控制效应无负面影响。     

白僵菌生物防治林中虫生真菌群落结构分析

对白僵菌生物防治林中虫生真菌群落的结构研究表明,长期接种式释放白僵菌的马尾松林中虫生真菌共有4属7种.球孢白僵菌的数量占绝对优势,为总数的63.22%;拟青霉次之,占25.86%;绿僵菌占9.20%;轮枝孢仅占1.72%.从寄主昆虫的多样性来看,球孢白僵菌和环链拟青霉的Brillouin多样性指数分别为3.564和2.315,均匀度分别为0.814和0.865;粉拟青霉和蜡蚧轮枝孢的多样性指数分别为1.471和0.862,均匀度为0.963和1.000而黄绿绿僵菌、金龟子绿僵菌和玫烟色拟青霉多样性和均匀度指标均较低.不同季节中被白僵菌侵染的寄主昆虫多样性指数呈现出春秋高、夏季低的趋势,反映了白僵菌种群的季节性变化.     

几种虫生真菌对斜纹夜蛾的致病性

用布氏白僵菌、球孢白僵菌、玫烟色拟青霉、绿僵菌和莱氏野村菌5种真菌的固体培养物,对斜纹夜蛾2、3龄幼虫进行了毒力测定.结果表明：布氏白僵菌和莱氏野村菌两种菌株对斜纹夜蛾幼虫有明显的致病效果,对2龄幼虫的致死中时(LT₅₀)分别为2.95 d和4.10 d,累计校正死亡率分别为100%和95.2%;对3龄幼虫的致病力低于2龄,致死中时(LT₅₀)分别为19.67 d和19.63 d,累计校正死亡率分别为56.6%和52.2%.玫烟色拟青霉、球孢白僵菌两菌株也有一定的致病力,对2龄幼虫的致死中时(LT₅₀)分别为4.89 d 和6.34 d,累计校正死亡率分别为85.7%和71.4%.     

球孢白僵菌分生孢子乳悬剂对甘蓝上桃蚜的田间控制效果

利用液-酵法生产球孢白僵菌(Beauveria bassiana)SG8702菌株的分生孢子粉,配制成含孢量为10^10个.ml^-1的孢子乳悬剂Ⅰ,在此基础上按1％(W／V)的比例舔加10％砒虫琳可湿性扮剂而得孢子乳悬剂Ⅱ．于2001年7月对两种孢子乳悬剂在云南昆明进行了自然条件下甘蓝上桃蚜(Myzus persicae)的田间小区(5．5m×4．8m)药效试验,各3个浓度(含孢量分别为10^7、10^6及10^5个·ml^-1常规喷雾处理,重复设清水喷雾对照,重复3次,随机区组排列．在喷菌后连续28d的田间蚜虫密度定期抽样调查中,乳悬剂Ⅱ的1000倍稀释液喷雾有效抑制了蚜虫数量增长,喷后策7—28天防效始终在90％以上．乳悬剂Ⅰ的相同稀释液喷雾对桃蚜的控制略逊于乳悬剂Ⅱ,但喷后第7天的相对防效也达到85％,此后维持防效70％以上达两周,策24天和28天才分别降至64．4％和52．6％．用含孢量10^6和10^5个·ml^-1的菌液喷雾,乳悬剂Ⅰ仍表现出明显的控蚜效果,而舔加微量砒虫琳的乳悬剂Ⅱ的控蚜效果总是优于同一浓度下的乳悬剂Ⅰ,昆明地区夏季温和而多小雨的气候有利于孢子乳悬剂发挥作用．     

琅琊山虫生真菌物种多样性和季节变化

在皖东琅琊山自然保护区设置的20个样方中共采集672份虫生真菌标本,分属于4科8属20种.优势种依次为球孢白僵菌、粉拟青霉、环链拟青霉、布氏白僵菌和玫烟色拟青霉,其中球孢白僵菌占绝对优势,相对多度高达73.8%.选用物种多度、Shannon-Wiener指数H′和Pielou均匀度E对琅琊山虫生真菌物种多样性和季节分布进行研究发现,虫生真菌数量丰富但物种多样性指数较低;夏季虫生真菌菌株最为丰富,均匀度相对较低,随着气温及降雨量的下降,菌株数量急剧下降,均匀度相对较高;不同季节白僵菌属的数量波动大,但拟青霉属波动较小.     

玫烟色拟青霉最适液体培养条件的研究

通过对不同营养和不同培养条件下玫烟色拟青霉菌丝生物量和产孢量的研究,结果表明:葡萄糖为玫烟色拟青霉液体培养的最适碳源,蛋白胨为该菌生长的最适氮源,C/N为10∶1~20∶1最适于玫烟色拟青霉菌丝生长和产孢;25℃2、4 h全光照条件,对该菌生长和产孢均有利。接种后144~168 h时,菌丝生物量和产孢量均达到高峰,分别为31.72 mg/mL、24.62孢子/mL,为黑暗条件下的1.5倍和18.3倍,因此玫烟色拟青霉液体发酵终点应选择在接种后144~168 h为最好。     

利用虫生真菌生物防治柑橘木虱的研究进展

柑橘木虱是柑橘黄龙病的重要传播虫媒。目前对柑橘黄龙病的防治尚缺有效的药剂和抗病品种,加强对柑橘木虱的防治,对控制柑橘黄龙病的蔓延具有重要意义。目前防治柑橘木虱多采用化学防治,杀虫剂的频繁使用造成了农药残留、环境污染、生物多样性被破坏和害虫产生抗药性等诸多问题,生物防治以其高效、低毒、低残留、不易产生抗药性等优点逐渐受到重视。昆虫病原真菌能侵入昆虫寄主体内,导致昆虫发病死亡,具有良好的病害流行潜力及生产应用便利性,利用昆虫病原真菌防治柑橘木虱具有广阔的发展空间。本文总结了用于柑橘木虱生物防治的虫生真菌种类,重点介绍了国内外利用球孢白僵菌、玫烟色棒束孢、淡紫紫孢菌、宛氏拟青霉、蜡蚧菌等虫生真菌在防治柑橘木虱中的应用,并对虫生真菌防治柑橘木虱的发展前景进行了展望,以期为柑橘黄龙病的防控提供借鉴。     

西花蓟马高毒力虫生真菌筛选及其生防应用潜力的研究进展

西花蓟马是一种外来入侵的世界性害虫,对农林业危害巨大。查阅国内外相关文献,综述了当前防治西花蓟马的虫生真菌的种类、高毒力菌株的筛选及防治现状。现已知西花蓟马的寄生病原真菌有5种,包括蜡蚧轮枝菌(半知菌:丝孢目)、球孢白僵菌(半知菌:丝孢目)、金龟子绿僵菌(半知菌:丝孢目)、玫烟色棒束孢(半知菌:束梗孢目)和小孢新接霉。其中,球孢白僵菌、金龟子绿僵菌在西花蓟马的生物防治中应用最广,具有良好的开发应用潜力,部分防效好的虫生真菌已申请专利及实现工厂化生产。     

Trials of Beauveria bassiana, Paecilomyces fumosoroseus and imidacloprid for management of Trialeurodes vaporariorum (Homoptera: Aleyrodidae) on greenhouse grown lettuce

Mineral oil-based emulsifiable preparations of Beauveria bassiana (Bb) and Paecilomyces fumosoroseus (Pfr) conidia were separately applied alone or together with low rates of imidacloprid 10% WP at 4.7% (Im 1), 14.0% (Im 2), and 23.3% (Im 3) of its recommended application rate, respectively, against the greenhouse whitefly, Trialeurodes vaporariorum, on lettuce grown in the greenhouse. Besides eight fungal treatments, the three low application rates of imidacloprid in the oil-based carrier and a blank control (CK) were also included as treatments of the trials conducted in 2002 and 2003. For the 12 treatments of each trial with three replicates, 1,000-fold aqueous dilutions were sprayed twice on transplanted lettuce at a 15-day interval at a rate of ∼1.43×10¹³ conidia ha^-1 for each fungal treatment or at one of the low rates of imidacloprid using a backpack hand-operated hydraulic sprayer. Based on whitefly densities, mortalities, relative efficacies and percent density declines estimated from whitefly counts made at 5-day intervals, all B. bassiana and P. fumosoroseus sprays were highly effective against T. vaporariorum compared to CK and Im 1-3 in both trials. In trial 1, the estimates of whitefly density decline and relative efficacy ranged from 44 and 72% (Bb) to 79 and 90% (Pfr+Im 2-3) on day 10 after the first spray and exceeded 94% for all fungal treatments 10 days after the second spray. Similar trends in whitefly control were also achieved in the corresponding treatments of trial 2. A more desirable and faster control resulted from fungal sprays containing more imidacloprid, but none of the three low imidacoprid rates alone suppressed the whitefly population more effectively than any fungal treatment despite a varying degree of efficacy. Moreover, P. fumosoroseus tended to be more effective against T. vaporariorum than B. bassiana when applied alone or together with the same low rate of imidacloprid but the difference in whitefly control eventually achieved was not significant between the two fungal agents. Thus, the emulsifiable preparations of both fungal agents can be considered as alternatives for whitefly management and for a slightly faster control can be applied together with imidacloprid at around 15% of its common application rate. An economic balance between the efficacy of whitefly control and the ease and cost of conidial production is needed when both fungi are incorporated into whitefly management.     

Cuticular lipids and silverleaf whitefly stage affect conidial germination of Beauveria bassiana and Paecilomyces fumosoroseus

Beauveria bassiana and Paecilomyces fumosoroseus are generalist entomopathogenic fungi that infect the silverleaf whitefly (Bemisia argentifolii). We found second and third instar whiteflies to be the most susceptible larval stage to both fungi. Conidia of B. bassiana germinated most readily on the cuticle of second instars (54% germinated) and P. fumosoroseus germination was highest on third instar cuticle (45%). Fourth instars (the ultimate instar) had low susceptibility to these pathogens, and spore germination on the cuticle of fourth instars was very low for B. bassiana (7%) and intermediate for P. fumosoroseus (33%). Cuticular lipids were found to have toxic or inhibitory effects on conidia of B. bassiana and P. fumosoroseus when the spores were germinated on nutrient agar in the presence of the lipids. In the absence of added nutrients, P. fumosoroseus conidial germination increased in the presence of the lipids. To test if the inhibitory effects of the lipids were due solely to hydrophobicity (preventing water from coming into contact with the conidia) we tested the effects of synthetic long-chain wax esters. The synthetic wax esters inhibited germination of P. fumosoroseus to a degree that was similar to the effect of the cuticular lipid extracts, but the synthetic lipids did not have a significant effect on B. bassiana. Thus, the thick coating of long-chain wax esters produced by whitefly nymphs affect spore germination of fungal pathogens, but whether they play a significant role in defense against disease is not clear.     

常用化学杀螨剂对两种生防真菌孢子的相容性测定

用营养液萌发法和平板萌发法测定了10种常用化学杀螨剂与球孢白僵菌（Beauveria bassiana）和玫烟色拟青霉（Paecilomyces fumosoroseus）分生孢子的生物相容性.结果表明,营养液萌发法比平板法灵敏.以24 h内的孢子萌发率作为指标,供试杀螨剂的常用浓度及其5和10倍稀释液对活孢率的影响在不同杀螨剂间差异极显著,并在两种真菌间也存在差异.三唑锡、浏阳霉素、三氯杀螨醇和阿维菌素对生防真菌孢子的抑制力很强,不宜混用.速螨酮、克螨特、乐斯本、尼索朗及双甲脒等杀螨剂与真菌孢子的相容性优良,可与菌剂田间混用.将速螨酮、克螨特和乐斯本分别按3种浓度与白僵菌的孢子悬乳剂混配后在4 ℃恒温和室内变温下长期共贮,结果显示,3种杀螨剂对孢子活力的影响迥异,混配制剂在室内变温下的贮存期均未达到12个月,离商品化的要求差距较大.乐斯本的长期相容性相对较优,与菌剂低浓度混配可在常温下贮存6.5个月,中浓度和低浓度混配在4 ℃下可贮存12个月.     

Virulence testing and extracellular subtilisin-like (Pr1) and trypsin-like (Pr2) activity during propagule production of Paecilomyces fumosoroseus isolates from whiteflies (Homoptera: Aleyrodidae)

To properly characterize several isolates of Paecilomyces fumosoroseus, a fungal entomopathogen of whiteflies (Homoptera: Aleyrodidae) and other insect pests for biocontrol purposes, virulence towards Trialeurodes vaporariorum, and subtilisin-like (Pr1) and trypsin-like (Pr2) protease activity during propagule production were investigated in monospore cultures (MCs). The virulence of three MCs towards second instar whiteflies was measured and expressed as lethal median concentration (LC50). Number and widthlength ratio of propagules (blastospores, hyphal bodies, short hyphae, submerged conidia) and extracellular proteolytic activity was determined simultaneously in liquid medium. Total protease activity was assayed with azocasein, Pr1 and Pr2 activity was determined with the substrates N-Succinyl-Ala-Ala-Pro-Phe-p-nitroanilide and N-Benzoyl-Phe-Val-Arg-pnitroanilide, respectively. Natural variability in virulence, propagule production and cuticle-degrading proteases among isolates was observed. Bioassays showed a LC50 of 1.1 x 1,000, 2.5 x 10,000 and 7.6 x 10,000 conidia/ml for MCs EH-506/3, EH-503/3 and EH-520/3, respectively, EH-506/3 being the most virulent isolate. Isolate EH-503/3 produced the highest yield of propagules (7.7 x 10000000 propagules/ml), followed by EH-520/3 with 6.4 x 10000000 and EH-506/3 with 1.0 x 10000000 propagules/ml. Subtilisin-like (Pr1) and trypsin-like (Pr2) activity was present in the three MCs. Subtilisin-like (Pr1) activity was highest (745.7 UPr1/ml at 120 h) in the most virulent isolate, EH-506/3, pointing at Pr1 as a phenotypic marker of virulence for P. fumosoroseus. EH-506/3 appears to be a good candidate for whitefly biocontrol due to its high virulence, Pr1 concentration and rapid transition to blastospores in submerged liquid medium.     

Effects of exogenous nutrients on conidial germination and virulence against the silverleaf whitefly for two hyphomycetes

Exogenous protein and sugar sources were tested for their impact on conidial germination of two silverleaf whitefly (Bemisia argentifolii) pathogens: Beauveria bassiana and Paecilomyces fumosoroseus. In liquid culture, sugars stimulated only 5-27% germination of B. bassiana and < or =11% germination of P. fumosoroseus, whereas, yeast extract or peptone stimulated 95-100% germination. In the absence of additional nutrients, agar alone stimulated approximately 50% germination. Storing spores for different periods of time did not alter their general response to exogenous nutrients. When spores were germinated before being applied to third instar B. argentifolii, mortality was as much as 2.45 times greater and occurred more rapidly than that for fresh spores. For ungerminated conidia, the mean time to death from infection was 5.45 (SE = 0.16) and 4.74 (SE = 0.08) days for application rates of 37 and 144 conidia x mm(-2), respectively. When conidia were germinated before application, infection times dropped to 4.58 (SE = 0.16) and 4.45 (SE = 0.10) days, respectively. A likely explanation for the greater pathogenicity and virulence of germinated over ungerminated B. bassiana conidia is that only a fraction of the spores applied to whitefly nymphs actually germinate on the cuticle. For some specialized applications, such as greenhouse production systems, it may be beneficial to germinate spores immediately prior to application.     

Development of a Spray-drying Technique for Submerged Spores of Entomopathogenic Fungi

The stability of blastospores or submerged conidia of entomopathogenic fungi is one of the key problems associated with the practical use of fungal biopreparations. A spray-drying technique was developed which allows the drying of blastospores and/or submerged conidia, here called submerged spores, without a significant loss of viability and with only a slight delay in eY cacy. The method was tested successfully using the fungal species Metarhizium anisopliae , M. flavoviride, Beauveria bassiana and Paecilomyces fumosoroseus . For all experiments, a laboratory spray dryer was used. The optimum inlet and outlet temperatures were found to be 64 2oC and 48 2oC respectively. The best protective agent for submerged spores was skimmed milk powder at concentrations of 10 or 20%. The addition of sugars, especially 2.5% sugar-beet syrup, slightly improved the viability after spray-drying. Submerged spores of eight isolates of M. anisopliae, M. flavoviride, B. bassiana and P. fumosoroseus were suspended in 20% skimmed milk powder and 2.5% sugar-beet syrup, and spray-dried. Germination rates of about 90% were achieved, which were comparable to those of freshly produced submerged spores. Finally, the virulences of spray-dried submerged spores of M. anisopliae (Ma 97) and M. flavoviride (Mfl 5) were tested in bioassays using third- and fourth-instar nymphs of the African locust, Locusta migratoria . In contrast to M. flavoviride , there was no significant diVerence in the median lethal time between spray-dried and fresh submerged spores of M. anisopliae . The investigations demonstrated that spray-drying is possible to preserve sensitive submerged spores of entomopathogenic fungi.     

新型球孢白僵菌孢子悬乳剂的高效杀蚜活性及其评价方法

用球孢白僵菌（Beauveria bassiana）SG8702的孢子悬乳剂与未剂型化孢子粉对桃蚜进行了杀蚜活性对比测定。孢子悬乳剂与孢子粉分别用水稀释成5个序列浓度,对甘蓝叶片上蚜虫进行相同时间的弥雾接种,前者孢子附着量分别为1.5～701.1个孢子/mm2 ,后者附着量分别为2.8～1005.9个孢子/mm2。蚜虫接种后置于23℃和12L：12D条件下饲养,定时观察8d。经时间—剂量—死亡率模拟分析,悬乳剂的剂量效应参数明显高于孢子粉,且杀蚜时间效应提前。用模型参数估计悬乳剂和孢子粉的LC50,接种后第4天分别为9.0和634个孢子/mm2,第7天为3.3和5.3个孢子/mm2。悬乳剂和孢子粉的LT50随叶面孢子附着量增大而下降,在100个孢子/mm2下为3.2d和4.5d。这表明孢子悬乳剂的杀蚜活性比未剂型化的孢子粉显著增强。作者讨论了杀虫微生物制剂评价的技术规范问题。     

Potential of fungi as biocontrol agents of polyphagotarsonemus latus (Acari: Tarsonemidae)

Infection of broad mites, Polyphagotarsonemus latus, by conidia of Beauveria bassiana, Hirsutella thompsonii, and Paecilomyces fumosoroseus conidia was investigated in the laboratory under controlled temperature and moisture conditions. Infection of P. latus by the fungus (LC₅₀) was related positively to the 1.16 × 10⁶ B. bassiana conidia per ml, 2.39 × 10³ H. thompsonii conidia per ml, and 1.29 × 10⁵ P. fumosoroseus conidia per ml. Mortality caused by B. bassiana occurred the fastest among densities fluctuating between 65 and 125 mites per leaf. The pathogens B. bassiana and P. fumosoroseus, adjuvants (oil and molasses), and the acaricide ABG6364, a microbial insecticide containing the Beta-exotoxin of Bacillus thuringiensis were evaluated for efficacy against P. latus in a greenhouse test. The B. bassiana treated plants had the greatest and most persistent effect on percentage mortality of total broad mites present per leaf (88 %) followed by the acaricide ABG6364. Use of adjuvants (oil and molasses) did not increase infection of P. latus.