椰子木蛾幼虫龄期的划分

椰子木蛾是为害棕榈科植物的重要危险性林业有害生物,2013年8月首次在我国海南发现,对我国椰子及棕榈产业造成严重的潜在威胁。龄期划分是深入研究椰子木蛾发生规律、生物学习性、预测预报以及防治适期的基础。头壳宽度可作为幼虫分龄的准确指标。本文通过林间收集椰子木蛾幼虫头壳和实验室饲养椰子木蛾并收集头壳的方法,通过测量与比较,运用频次分布与线性回归等,对椰子木蛾的龄期划分进行了研究,并依据Dyar法则和Crosby生长法则对划分结果进行了验证,确定其在林间和在实验室饲养条件下的龄数分别为5龄和5~8龄。室内饲养与室外相比,龄数增加,其原因可能是室内的环境条件如温度、湿度、光周期、食物营养等以及椰子木蛾自身遗传、种群密度等不同,室内环境条件不利而引起其龄期数增加。     

舞毒蛾脑和咽下神经节的形态及其三维模型构建

为探究舞毒蛾控制和分泌滞育激素的器官，于室内对舞毒蛾幼虫的中枢神经系统进行显微解剖，对其中枢神经系统和咽下神经节进行观察，并测量舞毒蛾1~5龄幼虫咽下神经节长度、宽度和面积，运用共聚焦激光扫描显微镜对脑和咽下神经节玻片逐层扫描，获取舞毒蛾幼虫脑和咽下神经节各高度的图像，将扫描后的图片描绘成1组多边图形，将其导入软件中，软件将多边图形叠加后构建其三维模型。结果显示，舞毒蛾幼虫的中枢神经系统包括脑、咽下神经节、3个胸部神经节和7个腹部神经节；舞毒蛾不同龄期幼虫的咽下神经节在外观形态上无较大差异；随着龄期增长，舞毒蛾咽下神经节的长度、宽度以及面积也不断增加，其中4龄幼虫咽下神经节的长度、宽度以及面积的增长速度最快，而5龄幼虫咽下神经节的长度、宽度以及面积的增长速度略微下降，1~3龄幼虫咽下神经节的长度、宽度以及面积的增长速度大致相同，均小于4龄和5龄幼虫。通过测量外部形态结构重建了舞毒蛾脑和咽下神经节的三维模型。     

赤斑白条天牛幼虫龄期划分指标的筛选

为了明确赤斑白条天牛幼虫的龄期和最佳分龄指标,为预测预报及防控提供理论依据,对幼虫的头壳宽、体长、体宽等3个外部形态指标进行测量,运用频次分布、Dyar定律、Crosby指数、Brook指数和回归分析对测量的数据进行统计分析。结果表明,赤斑白条天牛幼虫可分为6龄,头壳宽是判定龄期数的最佳形态指标,1～6龄头壳宽度平均值分别为2.08、3.27、4.74、6.51、7.73、9.25 mm;此外,体长和体宽均可作为判定龄期数的辅助指标。在确定幼虫龄期的基础上,对各龄期幼虫排出的木屑长度和宽度进行测量,回归分析表明,幼虫所排木屑长度和宽度也可作为估计幼虫龄期的重要指标,该指标有直观、易观察等优点,适合在监测与防治中推广应用。     

苜蓿籽蜂幼虫龄期的初步研究

通过测量苜蓿籽蜂幼虫头壳宽度的方法,对苜蓿籽蜂幼虫龄期划分进行了研究。结果得出苜蓿籽蜂幼虫共4龄,1龄～4龄幼虫的头壳宽度分别为(0.182±0.0093),(0.261±0.0093),(0.346±0.0098),(0.448±0.0109)mm。经统计分析得到其幼虫龄数(X)与头宽均值(Y)的关系式为Y=0.0883X+0.0885,r=0.9982。     

桔小实蝇幼虫龄期鉴别初步研究

为明确桔小实蝇幼虫龄期的鉴别依据和划分标准。本研究将桔小实蝇幼虫置于25±1℃、60%~70%RH条件下饲养,幼虫发育历期约为6~8 d,观察各龄幼虫的前气门、后气门、头咽骨和口钩等形态特征,并对桔小实蝇幼虫口钩长、口钩宽、体长和体宽4个形态指标进行测量。桔小实蝇幼虫分为3个龄期,各龄幼虫在形态特征上存在明显差异,口钩长度和宽度在龄期之间存在显著差异,1、2、3龄幼虫口钩平均长度分别为0.0846±0.0005 mm、0.1512±0.0013 mm、0.2913±0.0015 mm,口钩平均宽度分别为0.0116±0.0003 mm、0.0308±0.0007 mm、0.0677±0.0013 mm,皆明显分为3个范围且互不重叠,口钩长和口钩宽与龄数之间符合指数回归模型,口钩长符合y=0.045e~(0.6182x),口钩宽符合y=0.005e~(0.8816x)。因此口钩可作为幼虫龄期鉴别和划分的重要形态特征,幼虫体长、体宽因重叠严重、变异性大,不适合作为龄期划分的标准。     

柠条绿虎天牛幼虫龄期的划分

为明确柠条绿虎天牛Chlorophorus caragana XieWang幼虫的龄期,以便进行预测预报及采取防治措施。通过林间采集柠条绿虎天牛幼虫,并根据前胸背板宽、触角孔间距和体长3项形态指标的频次分布结果初步划分龄期,然后利用戴氏生长法则和线性回归进行验证。结果表明:柠条绿虎天牛幼虫可分为7龄,触角孔间距和前胸背板宽符合Dyar法则和Crosby法则并呈现明显的线性回归关系,可作为龄期划分的重要指标。体长不符合Crosby法则,不宜用于区分龄期。     

亚洲型舞毒蛾幼虫寄主选择与龄期关系初探

舞毒蛾是一种世界性的害虫,常被分为欧洲型和亚洲型2种类型,欧洲型舞毒蛾在传入美国之后造成了巨大危害。之前报道指出亚洲型舞毒蛾的寄主范围比欧洲型舞毒蛾的广,故造成的危害和损失更大,北美植物保护组织据此对中国的高风险港口实施了船舶特别检疫措施,对我国的进出口贸易产生了巨大影响。鉴于此,本实验以16种北美和中国常见的行道树种和绿化树种作为供试树种,分析了不同寄主植物对亚洲型舞毒蛾生长发育指标的影响规律。结果表明:饲喂白桦、加杨和糖槭的幼虫可以完成生活周期。饲喂杜松、女贞、大叶黄杨、红皮云杉、合欢、杂交鹅掌楸、马尾松、黑松和白皮松的幼虫在2龄以前全部死亡。虽然2龄以前幼虫饲喂北美乔松、油松和柿树后死亡率较高,但用人工饲料将幼虫饲养至4龄以后再替换饲喂以上3种植物,幼虫的死亡率则显著下降。分析表明,亚洲型舞毒蛾低龄幼虫(1、2龄)的寄主选择范围要窄于高龄幼虫(4龄以后的幼虫)。     

舞毒蛾种群分子系统学初步研究

本文以线粒体COI基因片段为分子标记,扩增了舞毒蛾部分种群的DNA序列,结合GenBank上发表的世界舞毒蛾种群相关序列,重建了舞毒蛾不同地理种群的系统发育关系.结果表明:世界舞毒蛾分成4支:冲绳舞毒蛾、北海道舞毒蛾地理种群、欧亚大陆舞毒蛾地理种群(包括日本大陆地区)和北美舞毒蛾地理种群.其中世界地理种群在COI基因上变异为0%～7%,中国种群在COI基因上没有差异.     

2种不同熏蒸剂对舞毒蛾不同虫态的杀灭效果

为判断溴甲烷和硫酰氟对舞毒蛾不同虫态的杀灭效果,在25℃下,分别在经过气密性检测的熏蒸桶内投入16、20、24、32 g/m3的溴甲烷和40、56、72、88 g/m3的硫酰氟,熏蒸处理舞毒蛾卵、幼虫、蛹和成虫4.5h.结果表明,经过4.5h熏蒸,杀灭舞毒蛾卵、1龄幼虫、蛹和成虫的溴甲烷浓度分别为32、20、24和16 g/m3,杀灭上述虫态硫酰氟浓度分别为88、56、72和40 g/m3.本文结果表明,舞毒蛾卵为最耐受溴甲烷和硫酰氟熏蒸的虫态,在目前口岸实际熏蒸处理中应充分考虑熏蒸剂对舞毒蛾卵的杀灭效果.     

前裂长管茧蜂个体发育研究

前裂长管茧蜂Diachasmimorpha longicaudata(Ashmead)是许多双翅目实蝇类害虫的重要寄生性天敌。在实验室条件下,以桔小实蝇Bactrocera dorsalis(Hendel)为繁育寄主,系统观测了前裂长管茧蜂个体发育过程中各虫态的特征及其相应的发育历期。观察结果表明,前裂长管茧蜂整个生活史由卵、幼虫、蛹及成虫四个阶段组成。其幼虫可划分为四个龄期,一龄幼虫具几质丁的坚硬头壳和镰刀状的颚,形态特征与行为习性与二、三、四龄幼虫完全不同。前裂长管茧蜂约需20天完成世代发育。卵、一龄幼虫、二龄幼虫、三龄幼虫及四龄幼虫的历期依次为1.91、2.02、1.75、2.04和2.31d;蛹的历期介于8~10d,雌性个体发育时间长于雄性。前裂长管茧蜂通常比未被寄生的寄主迟3~5d羽化,雌、雄蜂在羽化后即能交配、产卵,被寄生的桔小实蝇幼虫体表上会留下明显的深褐色产卵孔,寄主化蛹后产卵孔仍保留在其蛹壳上。     

乳化剂EL-40对高效氯氟氰菊酯微囊防控苗期棉蚜的调节作用

为探究乳化剂蓖麻油聚氧乙烯醚EL-40调控载药微囊释放性能的机制,评价载药微囊对非靶标生物的急性毒性,采用界面聚合法,通过调节乳化剂EL-40用量（0.5%、1.0%和2.0%）制备释放性能不同的2.5%高效氯氟氰菊酯微囊悬浮剂,分别于棉蚜Aphis gossypii发生初期与盛期进行施药,监测药剂处理后棉蚜与瓢虫的种群动态,明确其对棉田棉蚜的控制效果,并确定最佳施药时期。结果表明,微囊制备过程中,提高EL-40用量可降低囊壳致密度,进而加快载药微囊活性成分释放,当EL-40用量为0.5%、1.0%和2.0%时,添加润湿剂OP-10后载药微囊在叶面上的24 h释放百分比分别为18.02%、41.58%和63.84%。相对于乳油剂型,微囊化显著提高了2.5%高效氯氟氰菊酯对斑马鱼Danio rerio与七星瓢虫Coccinella septempunctata的安全性,且安全水平与微囊释放速率呈负相关,其中,含0.5% EL-40载药微囊的缓释性能最佳,对两者的急性毒性分别为270.55 μg/L（LC₅₀）与0.73 mg/L（LR₅₀）。相较于发生盛期施药,在发生初期施药对棉蚜种群的控制效果更好,且可避免对瓢虫种群造成伤害,其中2.0% EL-40载药微囊对棉蚜的控制效果最佳,施药后14 d棉蚜的校正虫口减退率为72.90%。表明在棉花苗期棉蚜发生初期使用含2.0% EL-40的2.5%高效氯氟氰菊酯微囊悬浮剂的控制效果更好,控制期更长。     

沃尔巴克氏体感染对黑腹果蝇头部转录组的影响

为明确沃尔巴克氏体Wolbachia对果蝇神经行为影响的分子机制,采取转录组测序技术对感染沃尔巴克氏体和未感染的黑腹果蝇Drosophila melanogaster头部样本进行转录组测序、组装、注释,筛选感染沃尔巴克氏体wMel和未感染黑腹果蝇头部转录组间的差异表达基因,并选择差异表达基因中差异倍数较大或与神经行为相关的基因进行qPCR验证。结果表明,感染沃尔巴克氏体wMel和未感染黑腹果蝇头部差异表达基因有679个（差异倍数≥2,P<0.05）,其中,由于感染沃尔巴克氏体wMel而上调表达的基因有566个,下调表达的基因有113个。GO功能注释分析显示,差异表达基因与代谢过程、催化和结合功能相关。KEGG通路注释分析发现,差异表达基因主要富集在蛋白消化与吸收、内分泌、神经活性配体-受体互作以及激素合成等通路中。从差异表达基因中筛选出11个基因进行qPCR验证,有9个基因的表达趋势与RNA测序结果一致。表明沃尔巴克氏体可广泛影响果蝇头部基因的表达水平,暗示可能由此影响宿主的神经行为。     

基于链特异性RNA-seq的禾谷镰刀菌全生活史转录组分析

为明确植物病原真菌禾谷镰刀菌Fusarium graminearum全生活史的转录组特征和基因表达模式,采用生物信息学技术对其生活史不同阶段15个时期或组织的链特异性RNA-seq数据进行分析。结果表明,共有8 106个基因在所有时期均有表达,为禾谷镰刀菌生活史核心基因,占总基因数的47.2%;有性生殖和侵染过程中表达的基因数相对较多,其中有性生殖后期表达的基因数最多,达15 221个;无性产孢和侵染小麦穗过程中基因表达水平整体较高,而分生孢子中基因表达水平最低。在燕麦培养基上禾谷镰刀菌气生菌丝的基因表达模式与侵染过程中的基因表达模式较为相似,而与营养生长菌丝的基因表达模式差异较大。该菌次生代谢物合成特征酶基因和分泌蛋白基因的表达模式均分成3类,即分别在侵染、营养生长和有性生殖过程上调表达,暗示其在生活史不同阶段的特异性功能。     

Germination of <Emphasis Type="Italic">Gibberella zeae</Emphasis> ascospores as affected by age of spores after discharge and environmental factors

The effects of age of ascospores (0–18 days after discharge), photon flux density (0–494 mol m^–2 s^–1 PAR), temperature (4–30 °C), frost (–15 °C for 30 min), relative humidity (RH; 0–100%), pH (2.5–6.5) and dryness (0 and 53% RH for up to 40 min) on the germination of the ascospores of the mycotoxin-producing fungus Gibberella zeae (anamorph Fusarium graminearum) were studied. Freshly discharged ascospores germinated within 4 h at 20 °C and 100% RH. The rate of germination and the percentage of viable ascospores decreased over time after the spores were discharged from perithecia. The time course of ascospore germination was not significantly affected by photon flux density. The period of time required to obtain 50% germinated ascospores at 100% RH was 26.90 h at 4 °C, 10.40 h at 14 °C, 3.44 h at 20 °C and 3.31 h at 30 °C. There was no significant effect of frost on the percentage of viable ascospores. A small percentage (6.6 ± 3.8%) of the ascospores germinated at 53% RH. At RH 84% and 20 °C almost 100% of the freshly discharged ascospores germinated. The time course of ascospore germination was affected by pH. The maximum rate of ascospore germination was estimated to be at pH 3.76. Ascospores lost their ability to germinate following exposure to 0% RH almost instantaneously. No germinating spores were detected after an incubation period of 1 min at 0% RH. Incubating the ascospores at 53% RH decreased the percentage of viable spores from 93 to 6% within 10 min. The data demonstrate that age of spores, relative humidity, temperature and pH, but not photon flux density, are key factors in germination of G. zeae ascospores.     

Effect of fungicides on the complex of <Emphasis Type="Italic">Fusarium</Emphasis> species and saprophytic fungi colonizing wheat kernels

Fusarium head blight of wheat, often associated with mycotoxin contamination of food and feed is caused by various Fusarium species. The efficacy of fungicide sprays for the control of the disease and mycotoxins varies from being highly effective to even increasing mycotoxin levels. The potential role of antagonistic fungi in this variability was investigated assessing sensitivity of Fusarium species and saprophytic fungi colonizing wheat kernels to fungicides. Saprophytes were tested for their antagonistic activity to the prevalent Fusarium species Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, and Fusarium poae. Fungal isolates from mature winter wheat kernels were Alternaria alternata, Arthrinium sp., Aspergillus niger, Epicoccum sp., Microdochium spp., Rhizopus oryzae and Trichoderma sp. In dual culture A. niger, R. oryzae and Trichoderma hamatum were more effective in reducing mycelial growth of Fusarium species than Microdochium majus; A. alternata and Epicoccum sp. were ineffective because of slow growth rates. Saprophytic fungi were sensitive to triazoles; however, prothioconazole and tebuconazole had stronger effects on mycelial growth of Fusarium species. ED₅₀ values also indicated significant differences in the sensitivity of Fusarium species to triazoles (range 0.1–1.7 mg l⁻¹). Azoxystrobin and fluoxastrobin were largely ineffective in inhibiting in vitro growth of Fusarium spp.; sensitivity of the other fungi was generally lower, except for M. majus which was highly sensitive. Due to differences in fungicide sensitivity among Fusarium spp. and ear-colonizing fungi antagonistic to Fusarium spp. fungicides are likely to modify the balance within the mycoflora of wheat ears which may also affect the mycotoxin contamination of grain.     

金银花尺蠖幼虫头部化学感受器扫描电镜观察

为了解金银花尺蠖Heterolocha jinyinhuaphaga Chu幼虫头部化学感受器的种类、形态、数量和分布,利用扫描电镜技术观察其老熟幼虫头部形态及触角和口器上的化学感受器。结果表明,金银花尺蠖老熟幼虫头部呈椭圆形;触角上着生1个毛形感受器、3个刺形感受器、1个栓锥形感受器和2个锥形感受器;上颚分布有1对毛形感受器;下颚分布有3个毛形感受器、2个刺形感受器、2个栓锥形感受器和8个锥形感受器;下唇须上有1个栓锥形感受器和1个刺形感受器;在吐丝器前方两侧有1对刺形感受器。金银花尺蠖幼虫触角上的化学感受器较少,口器附肢上化学感受器较多。     

Analysis of head and leaf reaction towards <Emphasis Type="Italic">Microdochium nivale</Emphasis>

This research examined the variation in the response of eight commercial wheat cultivars to Microdochium nivale isolates using both in vivo FHB tests (AUDPC and RHW measurements) and in vitro detached leaf assays (LGR). Irrespective of fungal variety, the two Italian cvs Fortore and Norba exhibited the greatest amount of visual disease symptoms (mean AUDPC=2.2 and 2.3, respectively), being significantly more susceptible than the other six cultivars (AUDPC 1.24) (P < 0.05). Irrespective of fungal variety, the Italian cv. Norba and the Irish cv. Falstaff were more susceptible than the other cultivars (except Fatima 2) in terms of RHW (P < 0.05), while the cvs Fortore, GK Othalom and Consort were more resistant than the other five cultivars (P < 0.05). In the detached leaf assay, the Hungarian cv. GK Othalom and the Italian cv. Norba were more susceptible (mean LGR=0.79 and 0.81 mm day^–1, respectively) to M. nivalethan the other six cultivars (mean LGR=0.51–0.72) (P < 0.05). Analysis of the relationship between head and leaf reaction to M. nivaleinfection revealed no significant correlation.     

Scab Response and Moniliformin Accumulation in Kernels of Oat Genotypes Inoculated with Fusarium avenaceum in Poland

Inoculation experiments with 14 genotypes of oats (10 cultivars and 4 lines) were performed during 1996, 1997 and 1998 in Sitaniec, South-Eastern Poland. Panicles of oats were inoculated with a conidial suspension of Fusarium avenaceum, which caused a reduction in yield by 33% and in 1000 kernel weight (TKW) by 21%. During the period between inoculation and harvest, F. avenaceum was able to accumulate moniliformin (MON) in kernels at an average level of 0.13mgkg^–1 (gg^–1). The highest reduction of yield components caused by the F. avenaceum inoculation was found for cv. Santor, followed by lines CHD 1171, STH 2795 and cvs: Kwant and Farys, while cvs Slawko, Dukat, Borys and Komes exhibited the highest resistance to the disease in terms of TKW and yield reductions after inoculation.     

Deoxynivalenol, Nivalenol and Moniliformin in Wheat Samples with Head Blight (scab) Symptoms in Poland (1998–2000)

Fusarium head blight (scab) epidemics of wheat occurred in uawy (Northern Poland) during 1998 and in Wielkopolska (West) and in Southern regions of Poland in 1999. Four species were identified in wheat heads with scab symptoms: Fusarium culmorum, Fusarium graminearum, Fusarium avenaceum and Microdochium nivale. A significant increase in the frequency of F. graminearum (between 23% and 38%), was observed, compared to about 10% during the previous decade. The mycotoxins deoxynivalenol (DON), nivalenol (NIV) and moniliformin (MON) in amounts up to 24.3, 14.2 and 1.72mgkg^–1respectively, were identified in kernels samples.