氯虫苯甲酰胺对黑肩绿盲蝽捕食功能的影响

为协调褐飞虱Nilaparvata lugens (Stal) 的化学防治和生物防治提供参考, 本研究采用稻茎浸渍法研究了氯虫苯甲酰胺对黑肩绿盲蝽Cyrtorhinus lividipennis (Reuter) 捕食褐飞虱功能反应的影响。结果表明: 在氯虫苯甲酰胺的推荐剂量下, 黑肩绿盲蝽功能反应模型的结构没有改变, 但影响到了模型的各项参数。在推荐剂量下, 氯虫苯甲酰胺可降低黑肩绿盲蝽的瞬时攻击率(a′); 药剂处理后黑肩绿盲蝽若虫对褐飞虱卵、1龄若虫和2龄若虫的处理时间(Th)比对照分别增加163.03%, 104.21%和95.11%, 而黑肩绿盲蝽成虫对它们的处理时间则分别增加81.97%, 102.45%和99.52%; 药剂处理后黑肩绿盲蝽日最大捕食量(Na*)降低, 其寻找效应(S)也减弱。研究表明氯虫苯甲酰胺对黑肩绿盲蝽捕食作用存在着不良影响。     

沫蝉的病原真菌新种——巨孢虫疫霉

在浙江省百山祖自然保护区虫生真菌调查中发现松树上的菱沫蝉(Agrophora sp.)的新病原真菌一种,因其分生孢子远大于任何已知种虫疫霉,故定为新种巨孢虫疫霉(Eryniagigantea Li,Chert et Xu)。其初生分生孢子长倒拟卵形或拟纺锤形,对称或略弯曲,42.6—76.7×l 2.3—26.0μm(平均57.6×l 8.6μm),长径比2.2—4.9(平均3.1);顶稍圆或尖削;基部乳突略钝,有时有孢领。次生分生孢子倒拟卵形至广倒拟卵形;毛管分生孢子未见。假根成束。假囊状体及休眠孢子未见。     

沫蝉的病原真菌新种——巨孢虫疫霉(英文)

在浙江省百山祖自然保护区虫生真菌调查中发现松树上的菱沫蝉(Agrophora sp.)的新病原真菌一种,因其分生孢子远大于任何已知种虫疫霉,故定为新种巨孢虫疫霉(Eryniagigantea Li,Chert et Xu)。其初生分生孢子长倒拟卵形或拟纺锤形,对称或略弯曲,42.6—76.7×l 2.3—26.0μm(平均57.6×l 8.6μm),长径比2.2—4.9(平均3.1);顶稍圆或尖削;基部乳突略钝,有时有孢领。次生分生孢子倒拟卵形至广倒拟卵形;毛管分生孢子未见。假根成束。假囊状体及休眠孢子未见。     

冠耳霉的分离和鉴定

本文报道了在福建南平发现的感染毛蠓(PsycAoda sp.)成虫的冠耳霉(Conidiobolutcoronatus)有关分离、培养和鉴定等工作。在虫尸上,分生孢子卵圆形至梨形,大小13.6—30.6×13.6—20.4μm,平均23.6×16.8μm。未见囊状体、假根及休眠孢子。易于人工培养。在培养基上初生分生孢子球形,直径26.4—49.6μm,平均37.8μm。初生分生孢子容易萌发,形成次生分生孢子、以及三生分生孢子、四生分生孢子。许多小型分生孢子外生于初生分生孢子上,卵形,平均大小16.5×13.2μm。分生孢子还可以转化成长柔毛分生孢子。     

氯虫苯甲酰胺对黑肩绿盲蝽实验种群的影响

采取稻茎浸渍法测定了氯虫苯甲酰胺对黑肩绿盲蝽毒力,利用生命表技术研究了氯虫苯甲酰胺对黑肩绿盲蝽实验种群的影响,为协调水稻害虫的化学防治和生物防治提供参考。结果表明,氯虫苯甲酰胺对黑肩绿盲蝽若虫LC50和LC10分别为83.5mg/L和61.3 mg/L,氯虫苯甲酰胺对黑肩绿盲蝽成虫LC50和LC10分别为64.3 mg/L和39.0 mg/L。氯虫苯甲酰胺对黑肩绿盲蝽若虫和成虫的LC10分别大于和接近于大田使用剂量40mg/L。以大田使用剂量40 mg/L氯虫苯甲酰胺稻茎浸渍法处理黑肩绿盲蝽3龄若虫后,其产卵期、寿命和产卵量降低了4.3 d、3.0 d和22.0粒,与对照相比差异显著,表明氯虫苯甲酰胺对当代成虫寿命与生殖力影响较大;药剂处理后次代种群的成虫前期延长了2.3 d;存活率、平均日产卵量跟对照相比明显降低;种群净增值率、周限增长率、内禀增长率跟对照相比明显降低,分别为21.0(对照63.3)、18.8(对照19.2)、0.16(对照0.22),而种群加倍时间延长为4.3(对照3.2);这些结果表明,在40 mg/L浓度下,氯虫苯甲酰胺能够降低黑肩绿盲蝽种群的增长。     

蚜虫的病原真菌新种——安徽虫疫霉

1984年初冬在安徽长江南北大面积蔬菜的桃蚜种群中发生真菌流行病。病原鉴定为虫霉目新种安徽虫疫霉(Erynia anhuiensis Li sp.nov)。分生孢子梗二歧分枝;初生分生孢子单核,双囊壁,长椭圆形、长卵形或倒拟卵形,前二者大小为17.1—33.3×5.9—12.9μm(平均24.7×8.3),长径比2.0—5.4(平均3.0),后者12.6—30.8×8.1—16.5μm(平均22.7×11.6),长径比1.4—2.5(平均2.0);有囊状体及假根,假根有固着器。外休眠孢子球形,光滑,透明,直径22.1—31.9μm(平均26.6)     

甘肃省一例苹果霉心病病原鉴定

【目的】对甘肃省天水市苹果霉心病病果中分离到的真菌进行病原鉴定。【方法】通过Koch’s法则证病,采用形态学和分子生物学方法对病菌进行种类鉴定。【结果】从甘肃省天水市苹果霉心病病果中分离得到一株淡灰褐色真菌,用该菌的分生孢子悬浮液接种苹果果实,可引起与自然发病相同的苹果霉心病症状。该菌的分生孢子具有不同的形态:产生于分生孢子盘上的分生孢子具3个隔膜,极少数4 5个隔膜,纺锤形或长椭圆形,淡褐色至褐色,基细胞色稍淡,附属丝缺,孢子大小为(12.95 20.42)μm×(4.98 7.97)μm[av.(16.75±1.89)μm×(6.47±0.86)μm];产生于丝状分生孢子梗及分生孢子堆上的分生孢子具2 9个隔膜,纺锤形、棒状或蠕虫状,初始色淡,渐呈褐色,(12.45 59.76)μm×(4.98 11.21)μm[av.(30.10±11.16)μm×(7.26±1.28)μm]。【结论】经形态学和分子生物学鉴定(GenBank登录号JF320818),将该病菌鉴定为Discostroma fuscellum(Berk.&Broome)Huhndorf。这是Discostroma fuscellum引起苹果霉心病在我国的首次报道。     

稻田氮肥施用量对黑肩绿盲蝽捕食功能的影响

在实验室条件下研究了黑肩绿盲蝽Cyrtorhinuslividipennis Reuter在不同含氮量稻株上对褐飞虱Nilaparvata lugens Stal卵和低龄若虫的捕食能力、对褐飞虱卵的捕食功能反应以及褐飞虱蜜露和水稻伤流液对其捕食 能力的影响。结果表明,黑肩绿盲蝽对褐飞虱卵和若虫的捕食量均与寄主植物的含氮量呈显著 负相关。黑肩绿盲蝽在相同氮肥施用量的稻株上连续饲养2代后对褐飞虱卵的捕食能力没有改变 。黑肩绿盲蝽对褐飞虱卵的功能反应呈Holling Ⅱ型方程,其参数瞬时发现率(a)和处置时间(T_h)只与寄主含氮量有关,而与黑肩绿盲蝽种群和褐飞虱卵的来源无关。 在高氮量稻株上黑肩绿盲蝽种群对褐飞虱卵的瞬时发现率(a)下降导致了功能反应的减弱, 而在相同含氮量稻株上黑肩绿盲蝽种群之间的捕食功能没有明显差异。黑肩绿盲蝽成虫取食水 稻伤流液和褐飞虱蜜露时寿命明显延长,取食高氮稻株的褐飞虱分泌的蜜露对延长黑肩绿盲蝽 雌成虫寿命的作用最大。但是,在高氮稻株上褐飞虱蜜露显著降低黑肩绿盲蝽的捕食能力。这 些结果表明黑肩绿盲蝽对褐飞虱自然控制作用的下降是稻田过量施用氮肥后褐飞虱种群增加的 主要原因之一。     

黑肩绿盲蝽耐饥饿能力的研究

【目的】为早期释放黑肩绿盲蝽Cyrtorhinus lividipennis提供理论依据,研究了黑肩绿盲蝽不同虫态耐受饥饿及低温的能力。【方法】室内条件下,比较了稻苗+水、无苗有水和无苗无水三种食物条件下黑肩绿盲蝽耐饥力大小。【结果】适温(26℃)下,黑肩绿盲蝽3龄若虫、5龄若虫和成虫在稻苗+水的存活时间显著高于无苗有水,无苗有水时的存活时间又显著高于无苗无水,表明稻苗对于黑肩绿盲蝽有营养作用,取食稻苗有助于提高黑肩绿盲蝽的耐饥力。黑肩绿盲蝽成虫耐饥力最强,3龄若虫和5龄若虫接近,有苗有水时,3龄若虫、5龄若虫和成虫的平均存活时间分别为2.10、2.22和4.25 d。在低温(15℃)下,水稻苗对黑肩绿盲蝽成虫的存活不利,有苗有水时雌雄成虫的存活时间均低于无苗有水处理,其中雌成虫两处理间的差异显著(P=0.001)。【结论】黑肩绿盲蝽对饥饿和低温有较强的耐受性,以成虫最强,水稻生长前期田间释放时以成虫为宜。     

弯孢虫疫霉的分离和鉴定

1984—1987年,在福建的南平、福州、南安等地持续发生了由弯孢虫疫霉(Eryniacurvlspora)感染而引起库蚊(culex sp.)成虫死亡的流行病,病原菌分生孢子梗掌状分枝;分生孢子浅绿色,窄而长,略弯曲,单核,双囊壁,含有多个小脂肪粒,大小29.7—39.6×13.2—19.8(平均32.5×16.1)μm,长宽比1.5—3.0(平均2.0);次生分生孢子梨形,基部为钝的乳突,中间有一大的脂肪粒,孢子大小16.6—19.9×11.6—14.9(平均18.7×13.7)μm;休眠孢子球形,棕褐色,直径23.2—33.2(平均29.5)μm;有假根及囊状体。     

蚜科专化菌努利虫疠霉菌种超低温储存

虫霉目真菌的活力对超低温储存较为敏感。储存法在大范围应用前,需对储存效果进行详细评估。将蚜科专化菌努利虫疠霉以初级分生孢子形式（2－3′105个孢子/mL）在-80℃超低温存储12个月。结果显示日常用于培养该真菌的含0.1%乳化芝麻油的萨氏培养基作为超低温保护基质能有效地储存努利虫疠霉孢子,比常见的冷冻保护剂如二甲亚砜和甘油的效果好。孢子悬液经解冻和培养后可获得最多的生物量,而且菌种保持了较高的生长速率。更重要的是,萨氏培养基的主要成分4%葡萄糖、1%蛋白胨和1%酵母粉在低温存储过程中发挥了协同作用,能保     

Antioxidant therapeutics: Pandora′s box

Evolution has favored the utilization of dioxygen (O₂) in the development of complex multicellular organisms. O₂ is actually a toxic mutagenic gas that is highly oxidizing and combustible. It is thought that plants are largely to blame for polluting the earth′s atmosphere with O₂ owing to the development of photosynthesis by blue-green algae over 2 billion years ago. The rise of the plants and atmospheric O₂ levels placed evolutionary stress on organisms to adapt or become extinct. This implies that all the surviving creatures on our planet are mutants that have adapted to the “abnormal biology” of O₂. Much of the adaptation to the presence of O₂ in biological systems comes from well-coordinated antioxidant and repair systems that focus on converting O₂ to its most reduced form, water (H₂O), and the repair and replacement of damaged cellular macromolecules. Biological systems have also harnessed O₂′s reactive properties for energy production, xenobiotic metabolism, and host defense and as a signaling messenger and redox modulator of a number of cell signaling pathways. Many of these systems involve electron transport systems and offer many different mechanisms by which antioxidant therapeutics can alternatively produce an antioxidant effect without directly scavenging oxygen-derived reactive species. It is likely that each agent will have a different set of mechanisms that may change depending on the model of oxidative stress, organ system, or disease state. An important point is that all biological processes of aerobes have coevolved with O₂ and this creates a Pandora′s box for trying to understand the mechanism(s) of action of antioxidants being developed as therapeutic agents.     

诺氏虫疠霉生物学特性的研究

通过对诺氏虫疠霉生物学特性的研究,明确了该菌孢子萌发,生长的适温范围为15℃-25℃,萌发最适湿度为100％,最适pH为9－10。紫外线对诺氏虫疠霉分生孢子有强烈杀伤作用,照射10分钟,萌发率降低41．9％,不同光照处理间菌落生长差异显,全光照可完全抑制菌落生长,明暗交替最地菌落生长和产孢。     

Pandora neoaphidis transmission and aphid foraging behaviour

Pandora neoaphidis is an aphid-specific entomopathogen that produces infective conidia. As aphid movement increases, so does the likelihood of contact with conidia. Volatile distress signals released in response to aphid infestation as an indirect defence against herbivory may affect aphid foraging and, therefore, the fungus-aphid interaction. In this study, two different methods were used to investigate the effect of plant volatiles and P. neoaphidis-sporulating cadavers on (1) the colonisation of Vicia faba plants by Acyrthosiphon pisum and (2) P. neoaphidis transmission. This study indicates that A. pisum does not avoid bean plants containing P. neoaphidis and that transmission of conidia occurs during plant colonisation and, to a lesser extent, during in situ feeding. Although significantly more aphids were recovered from damaged plants compared to undamaged plants, the likelihood of infection was not affected by previous infestation by aphids.     

环境因子对努利虫疠霉产孢和孢子萌发的影响

探讨努利虫疠霉Pandoranouryi(Remaudi埁re&Hennebert)H櫣mber在田间蚜虫种群中发生与流行的规律,研究外界环境因子对感菌虫尸产孢和孢子萌发的影响。结果表明,处于水琼脂培养平板上感染努利虫疠霉的桃蚜虫尸在8~25℃的温度范围内均能产生大量的初生分生孢子,在30℃下,仅弹射极少量孢子。8℃下,孢子弹射可以持续120h,当温度高于15℃,大部分的孢子会在48h内完成弹射。相对湿度小于95%,虫尸停止产孢。20℃下,光照条件不会影响虫尸弹射孢子的总量。在8℃和30℃时,24h后处于水琼脂培养平板上的孢子萌发率分别为45.23%和61.74%,显著低于15~25℃温度范围内的孢子萌发率(95%以上)。处于叶片上的真菌孢子,当相对湿度大于74%时出现萌发,但在盖玻片的表面,当湿度低于100%时未发现孢子萌发。     

飞虱虫疠霉杀蚜效果及开发应用前景

通过比较飞虱虫疠霉 (Pandoradelphacis)与其它几种常见蚜虫专化性病原真菌新蚜虫疠霉(P .neoaphidis)、安徽虫瘟霉 (Zoothphoraanhuiensis)和根虫瘟霉 (Z .radicans)对桃蚜 (Myzuspersicae)毒力 ,证实了该菌的杀蚜应用潜力。时间 -剂量 -死亡率模型分析表明 ,飞虱虫疠霉杀蚜的各项毒力指标与其它几种虫霉相似或略高 ,但杀蚜速率更快。同时对培养性状、产孢特性和生长适温等的比较研究发现 ,该菌具有易发酵生产、产孢能力强和温度生长范围宽等特点 ,是一种较为理想的有望研制开发成杀蚜真菌制剂的病原菌。此外 ,根据虫霉孢子主动弹射的生物学特性 ,提出了该菌的适用剂型 ,并对它们的流行学特性及其在设栽培中的应用前景进行了讨论。     

Transmission of Pandora neoaphidis in the presence of co-occurring arthropods

Transmission of the entomopathogenic fungus Pandora neoaphidis to the nettle aphid Microlophium carnosum was assessed in the presence of arthropods that co-exist with the fungus within the habitat but do not compete for aphid hosts. The presence of a parasitoid significantly enhanced transmission, and transmission rates were similar for both enemy and non-enemy parasitoids. Although herbivory of nettle leaves by Peacock butterfly (Inchis io) caterpillars indirectly reduced the number of M. carnosum by >30% due to a reduction in leaf area for feeding, the addition of I. io significantly increased transmission of P. neoaphidis in the remaining aphids. It is likely that enhanced transmission in the presence of A. rhopalosiphii and I. io is due to disturbance and subsequent movement of the aphid, resulting in contact with conidia deposited on the leaf surface. The presence and impact of co-occurring arthropods should be taken into consideration when assessing the transmission of fungal entomopathogens.     

A PCR-based tool for the cultivation-independent monitoring of Pandora neoaphidis

Pandora neoaphidis is one of the most important fungal pathogens of aphids and has a great potential for use in biocontrol. Little is known on how this fungus persists in an area and in particular on its overwintering strategies. It is hypothesized that natural areas play an important role for survival and that soil may serve as a source of inoculum for new aphid populations in spring. To test these hypotheses, a cultivation-independent PCR-based diagnostic tool was developed, that allows the detection of P. neoaphidis in the environment. Two P. neoaphidis specific PCR primer pairs were designed, targeting sequences in the ribosomal RNA gene cluster. Specificity of both primer pairs was demonstrated with P. neoaphidis and non-target close entomophthoralean relatives. Moreover, single amplicons of expected sizes were obtained with both primer pairs from various environmental sample types, including aphid cadavers, plant material, and soil. The PCR-based diagnostic tool was applied to investigate the persistence of P. neoaphidis in soil samples obtained in 2004/2005 from a nettle field harboring infected aphids in fall 2004. P. neoaphidis was detected in every sample collected in November 2004 and March 2005, suggesting an overwintering stage of P. neoaphidis in top soil layers. The developed cultivation-independent PCR-based tool will be valuable for further investigation of the ecology of P. neoaphidis and for the development and future implementation of management strategies against aphids involving conservation biocontrol.     

Response of the entomopathogenic fungus Pandora neoaphidis to aphid-induced plant volatiles

We used a model plant-aphid system to investigate whether the aphid-specific entomopathogenic fungus Pandora neoaphidis responds to aphid-induced defence by the broad-bean plant, Vicia faba. Laboratory experiments indicated that neither in vivo sporulation, conidia size nor the in vitro growth of P. neoaphidis was affected by Acyrthosiphon pisum-induced V. faba volatiles. The proportion of conidia germinating on A. pisum feeding on previously damaged plants was significantly greater than on aphids feeding on undamaged plants, suggesting a direct functional effect of the plant volatiles on the fungus. However, there were no significant differences in the infectivity of P. neoaphidis towards A. pisum feeding on either undamaged V. faba plants or plants previously infested with A. pisum. Therefore, these results provide no evidence to suggest that P. neoaphidis contributes to plant indirect defence strategies.