黄绿绿僵菌对褐飞虱和白背飞虱不同发育阶段的病原性的研究

本文报道了不同孢子浓度下黄绿绿僵菌对褐飞虱和白背飞虱不同发育阶段的易感性和毒力的研究。实验设10.5孢子/mm2,116.7孢子/mm2和1027.1孢子/mm2三种孢子剂量,两种飞虱分为幼龄若虫(1龄和2龄若虫)、高龄若虫(3、4、5龄若虫)和成虫三个发育阶段。实验发现褐飞虱与白背飞虱的三个发育阶段对黄绿绿僵菌的不同浓度的孢子液有不同程度的易感性。黄绿绿僵菌对褐飞虱幼龄若虫的毒力指标LT50在三种孢子剂量下依次为>21、20.82和16.55;对高龄若虫的LT50在三种孢子剂量下依次为17.68、15.49和13.98;而对成虫的LT50在三种孢子剂量下依次为17.10、12.57和9.14。黄绿绿僵菌对白背飞虱幼龄若虫的毒力指标LT50在三种孢子剂量下依次为>21、17.29和13.13;对高龄若虫的LT50在三种孢子剂量下依次为16.94、15.02和13.03;而对白背飞虱成虫的LT50在三种孢子剂量下依次为12.78、10.16和7.64。二者的成虫的易感性比若虫的易感性强,高龄若虫的易感性比幼龄若虫的强。白背飞虱比褐飞虱对黄绿绿僵菌更加敏感。二者的死亡率随孢子浓度的增大而增大。     

Virulence of Metarhizium flavoviride 82 to different developmental stages of the brown planthopper, Nilaparvata lugens (Hemiptera:Delphacidae)

对水稻重要害虫褐飞虱Nilaparvata lugens目前市场上尚无一种理想的微生物杀虫剂.昆虫病原真菌具有从体壁侵入的能力因而对刺吸性害虫的防治具有优势.为此,本研究选用不同原寄主和来源地的3种昆虫病原真菌(金龟子绿僵菌Metarhizium anisopliae、黄绿绿僵菌Metarhizium flavoviride和球孢白僵菌Beauveria bassiana)的12个不同菌株,以1 100孢子/mm2孢子悬浮液进行室内毒力测定.结果表明:在参试的不同菌种12个菌株中,黄绿绿僵菌Mf82菌株对褐飞虱成虫致病力最高,10 d累计校正死亡率为83.5％,致死中时(LT50)为4.6d.其不同浓度孢子液对褐飞虱3个发育阶段有不同程度的致病力,毒力大小顺序为成虫＞高龄若虫＞低龄若虫.黄绿绿僵菌孢子液对各处理稻株褐飞虱产卵痕部位、卵粒均有侵染作用,10d侵染率分别为66.7％和51.2％,卵龄越低,侵染效果越好,卵龄为0.5d时侵染率最高.本研究表明黄绿绿僵菌Mf82菌株对褐飞虱成虫、若虫和卵均有较强的致病性,是一株极具应用潜力的生防真菌.     

黄绿绿僵菌Mf82菌株对不同虫态褐飞虱的毒力

对水稻重要害虫褐飞虱Nilaparvata lugens目前市场上尚无一种理想的微生物杀虫剂。昆虫病原真菌具有从体壁侵入的能力因而对刺吸性害虫的防治具有优势。为此, 本研究选用不同原寄主和来源地的3种昆虫病原真菌（金龟子绿僵菌Metarhizium anisopliae、 黄绿绿僵菌Metarhizium flavoviride和球孢白僵菌Beauveria bassiana）的12个不同菌株, 以1 100孢子/mm²孢子悬浮液进行室内毒力测定。结果表明： 在参试的不同菌种12个菌株中, 黄绿绿僵菌Mf82菌株对褐飞虱成虫致病力最高, 10 d累计校正死亡率为83.5%, 致死中时（LT₅₀）为4.6 d。其不同浓度孢子液对褐飞虱3个发育阶段有不同程度的致病力, 毒力大小顺序为成虫>高龄若虫>低龄若虫。黄绿绿僵菌孢子液对各处理稻株褐飞虱产卵痕部位、 卵粒均有侵染作用, 10 d侵染率分别为66.7%和51.2%, 卵龄越低, 侵染效果越好, 卵龄为0.5 d时侵染率最高。本研究表明黄绿绿僵菌Mf82菌株对褐飞虱成虫、 若虫和卵均有较强的致病性, 是一株极具应用潜力的生防真菌。     

几种虫生真菌菌株的培养性状及其对褐飞虱的毒力

从褐飞虱Nilaparvata lugens (St(a)l)罹病虫体上新分离出的一种黄绿绿僵菌菌株Metarhizium flavoviride (Mf82),与实验室保存的黄绿绿僵菌、金龟于绿僵菌和白僵菌3种菌种5个菌株作为对比,研究了在SDAY和PDA培养基上的培养性状,并测定了它们对褐飞虱成虫的毒力.结果表明:...     

褐飞虱高毒力绿僵菌菌株的筛选

从田间褐飞虱Nilaparvata lugens (St?l)罹病虫体上新分离鉴定一株黄绿绿僵菌Mf82,将其与实验室保存的8株绿僵菌Metarhizium spp.一起,分别测定其对褐飞虱成虫毒力和几丁质酶活力,并用扫描电镜观察侵入昆虫表皮的过程和体表的形态变化,进而分析侵入能力与几丁质酶的相关性。结果表明：菌株Mf82累计校正死亡率和几丁质酶活力均最高,为82.1%和9.78U/mg,与其他菌株差异显著。同时,扫描电镜照片显示Mf82分生孢子既可以由褐飞虱体壁节间膜和凹陷处侵入,还可以从含几丁质较多的胸部背板侵入。比较9株绿僵菌菌株菌落生长速度、产孢初始时间、产孢量和萌发率显示,Mf82菌株具有生长速度快、产孢初始时间短、萌发率高和产孢量大等优点,可见筛选的Mf82菌株致病力强,在褐飞虱的微生物防治方面将有良好的应用前景。     

黄绿绿僵菌对两种稻田蜘蛛捕杀褐飞虱作用的影响

在室内研究了喷施黄绿绿僵菌Metarhizium anisopliae var. acridum Driver et Milner孢子悬液对稻田蜘蛛捕杀褐飞虱作用的影响。结果表明,黄绿绿僵菌不感染拟水狼蛛Pirata subpiraticus Bsenberg et Strand和食虫沟瘤蛛Ummeliata inse cticeps Bsenberg et Strand,只对蜘蛛喷施菌液不影响它们的捕杀褐飞虱的能力。而对褐飞虱喷施黄绿绿僵菌液后,褐飞虱活力明显下降,导致蜘蛛对其捕杀效果显著提高。在喷施黄绿绿僵菌106 、107、108/mL孢子浓度后,拟水狼蛛的平均捕杀量分别为10.5头/d、11.1头/d和11.4头/d,食虫沟瘤蛛的平均捕杀量分别为3.8头/d、4.3头/d和4.7头/d,均显著大于对照组。对蜘蛛和褐飞虱同时喷施黄绿绿僵菌不影响前者的捕杀力。这些结果提示,在稻田施用黄绿绿僵菌防治稻飞虱对蜘蛛天敌没有不良影响。     

黄绿绿僵菌Ma130821对暗黑鳃金龟幼虫的室内毒力及毒杀作用研究

采用浸渍法测定了黄绿绿僵菌Metarhizium flavoviride菌株Ma130821对暗黑鳃金龟Holotrichia parallela Motschulsky幼虫的毒力,采用室内盆栽拌土法、环施法和穴施法施用黄绿绿僵菌Ma130821分生孢子粉,测定了该菌株对暗黑鳃金龟幼虫的毒杀效果。结果表明:黄绿绿僵菌菌株Ma130821对暗黑鳃金龟3龄幼虫的侵染致病效应可利用"时间—剂量—死亡率"模型进行模拟分析和参数估计分析,侵染效应常数为0. 597。接种后第3天该菌株对暗黑鳃金龟3龄幼虫的致死剂量LC_(50)和LC_(90)的对数值分别为9. 2182±0. 2968和11. 2291±0. 4385。在6. 20×108孢子/m L黄绿绿僵菌菌悬液对暗黑鳃金龟幼虫侵染致病的LT_(50)和LT_(90)分别为1. 5 d和3. 8 d。室内盆栽拌土法、环施法和穴施法施用黄绿绿僵菌菌株Ma130821分生孢子粉对暗黑鳃金龟3龄幼虫均具有良好的毒杀作用,其中拌土法施用后对暗黑鳃金龟幼虫的毒杀效果高于其他两种方法,拌土法、环施法和穴施法施用后对暗黑鳃金龟3龄幼虫的累积死亡率分别为95. 69%、84. 35%和57. 43%,累积僵虫率分别为99. 65%、98. 65%和99. 37%。综合以上结果,黄绿绿僵菌Ma130821对暗黑鳃金龟幼虫具有良好的毒力和毒杀作用,在暗黑鳃金龟的生防制剂开发中具有良好潜力。     

绿僵菌及其与dsRNA混合使用对褐飞虱的防治效果

褐飞虱Nilaparvata lugens Stl是我国重要的迁飞性水稻害虫,本文研究了金龟子绿僵菌Metarhizium anisopliae及其与dsRNA混合使用对褐飞虱的防治效果。绿僵菌悬浮液1.6×108孢子/m L至8×106孢子/m L对褐飞虱2龄、4龄和成虫进行喷药,发现1.6×107孢子/m L对各个虫态虫龄均有良好致死效果,并且成虫和4龄若虫均好于2龄若虫。在交配行为上来看,绿僵菌处理过的褐飞虱成虫活跃度非常低,从配对开始一直到交配结束的各个阶段都受到明显影响,处理组3 h的交配率只有3.70%,而对照组的交配率为24.44%。还把褐飞虱几丁质合成酶基因A的dsRNA与绿僵菌混合使用防治褐飞虱2龄和4龄若虫,结果表明0.5μg/μL ds CHSA与绿僵菌混合使用的防治效果最好,2龄若虫的死亡率为89.63%,4龄若虫的死亡率达到93.94%。而0.2μg/μL ds CHSA与绿僵菌的混合,对2龄和4龄若虫的致死率为65.56%-76.52%。研究结果为褐飞虱的生物防治提供了新的思路。     

绿僵菌MaFZ-13对橙带蓝尺蛾幼虫致病力及林间防治效果

【目的】橙带蓝尺蛾Milionia basalis近年来在我国南方地区严重危害罗汉松Podocarpusmacrophyllus和竹柏Podocarpus nagi,扩散蔓延速度快,造成了很大的损失。本研究旨在评估金龟子绿僵菌Metarhizium anisopliae MaFZ-13菌株对橙带蓝尺蛾幼虫的致病力,探寻橙带蓝尺蛾生物防治新资源。【方法】通过绿僵菌MaFZ-13不同浓度(1.0×10⁵~1.0×10⁹孢子/mL)孢子悬浮液接种橙带蓝尺蛾幼虫,运用时间-剂量-死亡率(TDM)模型对生物测定结果进行分析,同时通过林间喷施1.0×10⁸孢子/mL绿僵菌孢子悬浮液进行林间防治效果试验。【结果】橙带蓝尺蛾幼虫累计死亡率随着绿僵菌MaFZ-13孢子悬浮液孢子浓度的增加和接种时间的延长而增大。接种1.0×10⁹孢子/mL孢子悬浮液8 d后以及接种1.0×10⁸孢子/mL孢子悬浮液10 d后,幼虫死亡率均达到100%;接种1.0×10⁷孢子/mL孢子悬浮液15 d后幼虫死亡率为95.6%。应用TDM模型对生测数据进行分析,结果表明所建模型通过Hosmer-Lemeshow拟合异质性检验,并由模型估算出了该菌株对橙带蓝尺蛾幼虫的致死剂量和致死时间。绿僵菌MaFZ-13菌株接种4, 5, 6和7 d后的半致死剂量(LC₅₀)对数估计值分别为7.99, 7.12, 6.46和5.83。以1.0×10⁷, 1.0×10⁸和1.0×10⁹孢子/mL的孢子浓度接种时,绿僵菌MaFZ-13菌株对橙带蓝尺蛾幼虫的LT₅₀值分别为5.19,3.99和2.81 d。林间用1.0×10⁸孢子/mL绿僵菌孢子悬浮液喷洒9 d后橙带蓝尺蛾幼虫死亡率可达到85.8%,防治效果为85.05%。【结论】绿僵菌MaFZ-13对橙带蓝尺蛾幼虫具有较强的致病力,林间防治效果良好,具有较好的应用潜力。     

绿僵菌与3种杀虫剂混配对樟巢螟的协同作用

采用定量喷雾法测定了绿僵菌、白僵菌以及3种杀虫剂对樟巢螟Orthaga achatina低龄幼虫的室内毒力,并测定了金龟子绿僵菌Ma09与3种杀虫剂混配后的协同作用。结果显示：4种昆虫病原菌菌株均对樟巢螟2~3龄幼虫具有较好的致死效果,用绿僵菌和白僵菌孢悬液处理后,死亡高峰期在3~4 d;白僵菌GDLY9的防治效果最好,处理浓度为1×109孢子/mL下LT50和LT90分别为3.01、3.95 d,金龟子绿僵菌Ma09、3297效果相当,黄绿绿僵菌Mf985的LT50相对低一些,但是LT90优于金龟子绿僵菌Ma09和3297。金龟子绿僵菌Ma09与苯氧威、除虫脲和短稳杆菌混配后均表现出增效作用,协同指数分别为20.43、27.53和33.13。     

黄绿绿僵菌对褐飞虱侵染过程的扫描电镜观察

本实验利用扫描电镜观察了黄绿绿僵菌Metarhizium flavoviride菌株分生孢子对褐飞虱Nilaparvata lugens(St(a)l)的侵染过程.结果表明:分生孢子多分布在褐飞虱节间膜、体表的褶皱凹陷等部位,主要以芽管或产生附着胞入侵,然后在体表长出菌丝和产孢.菌体进入寄主血腔后,利用体腔内营养大量增...     

Effects of Metarhizium anisopliae on Meccus pallidipennis (Hemiptera: Reduviidae) over different types of wall surfaces

The entomopathogenic fungus Metarhizium anisopliae is virulent for the insect triatomine Meccus pallidipennis. To evaluate the functionality of a fungal formulation (vegetable oil and emulsifiers) of this fungus, virulence was assayed by insect mortality on the pronotum of third instar nymphs (N3) M. pallidipennis in laboratory conditions and ST₅₀ was calculated. Mortality was evaluated directly: 100%, 97.33% and 98.66% mortalities were caused by formulation, emulsified formulation and fungal conidia, respectively, at day 8 of insect infection. Another bioassay was carried out in simulated external conditions (peridomicility) using red and gray brick walls, a stone fence and mountain soil (experimental units). These simulated conditions were infected with 10?ml of a 1?×?10⁹?conidia/ml emulsified formulation by means of a manual sprinkler prior to the placement of the nymphs. Ten N3 M. pallidipennis were deposited in each experimental unit and insect mortality was monitored every 12?h for 22 days. Each treatment was replicated four times. With the red brick wall, a mortality of 90% at day 22 and a ST₅₀ of 15 days were obtained on N3 M. pallidipennis; with the gray brick wall, 100% mortality and a ST₅₀ of 13 days; and with the stone fence, 88.33% mortality and a ST₅₀ of 21 days. The results obtained in this research work indicate that the formulation with conidia of the M. anisopliae strain EH-473/4 may be auxiliary in the development of strategies for the control of Chagas disease insect transmitters such as M. pallidipennis.     

Susceptibility of Ixodes scapularis (Acari: Ixodidae) to Metarhizium brunneum F52 (Hypocreales: Clavicipitaceae) using three exposure assays in the laboratory

An emulsifiable concentrate (EC) and granular (G) formulation of the entomopathogenic fungus, Metarhizium brunneum strain F52 (formerly Metarhizium anisopliae strain F52) were tested against unfed adults and nymphs of Ixodes scapularis Say in the laboratory. Three exposure methods; dip, surface contact, and direct spray application, and three exposure time intervals (3, 30, and 300 min) were used to evaluate the EC formulation. Application rates ranged from 2.6 x 10(2) to 2.6 x 10(8) conidia/cm2. The surface treatment was used for granular formulation with concentrations ranging from 2.3 x 10(5) to 2.3 x 10(7) conidia/cm2 for same three exposure times. Both the EC and G formulations of this fungus were highly pathogenic against I. scapularis adults and nymphs. Logistic regression analysis found formulation, spore concentration, time of exposure, and observation period were significant or highly significant factors influencing tick mortality. For adult I. scapularis, the spray application with the EC formulation of M. brunneum F52 resulted in a lower LC50 (5.9 x 10(4) conidia/cm2) at 30 min than surface exposure to the EC (LC50 = 1.3 x 10(6) conidia/cm2) or G formulation (LC50 = 8.1 x 10(5) conidia/cm2). At higher concentrations, fungal activity was evident in adult I. scapularis held at 5 degrees C suggesting the fungus may provide control in the cooler fall season. While the observed pathogenicity of a fungus against ticks can be dependent upon the bioassay assessment, we found nymphs and adults of I. scapularis to be highly susceptible to M. brunneum F52, regardless of the exposure method used.     

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。     

Cellular and humoral immune defenses of Oxya japonica (Orthoptera: Acrididae) to entomopathogenic fungi Metarhizium anisopliae

One Indonesian isolate of the fungus Metarhizium anisopliae, named Majalengka strain, was evaluated not only for its virulence but also for the immune response of rice grasshopper Oxya japonica (Orthoptera: Acrididae) as a target organism. Five aqueous suspensions with different conidia concentrations in logarithmic series were prepared. The fungus showed high virulence as it caused 100% mortality at low conidia concentration (1.5 × 10² conidia/mL). Remarkable changes in the cellular and humoral responses were also observed when adult grasshoppers were infected with the fungus. The number of hemocytes decreased significantly within 12 h after infection. In addition, the total number of granulocytes increased rapidly in the first 12 h then gradually decreased 24 and 48 h after infections, while the number of coagulocytes fluctuated over time. The infection influenced the humoral response by increasing the phenoloxidase activity.