入侵害虫南美斑潜蝇在西藏首次发现及其寄生蜂调查

【目的】南美斑潜蝇Liriomyza huidobrensis为我国重要的入侵害虫,我们于2017年7月首次发现其已扩散至西藏。本研究旨在了解西藏地区南美斑潜蝇的发生现状及其寄生蜂种类。【方法】2017和2018年6月上旬-9月中旬对西藏拉萨、林芝、山南和日喀则4个地区的南美斑潜蝇的发生危害及其寄生蜂组成进行了调查采样。【结果】调查的西藏这4个地区均发现南美斑潜蝇分布和危害;温室发生时间为6月上旬-9月中旬,而露地的发生高峰在7月下旬-8月上旬。其寄主植物有9科21种,主要有豆科(Fabaceae)、茄科(Solanaceae)和伞形科(Umbelliferae)等,主要嗜好经济作物有豇豆Vigna unguiculata, 扁豆Lablab purpureus , 莴笋Lactuca sativa var. angustana和白菜Brassica rapa ssp. pekinensis。其寄生蜂包括姬小蜂科(Eulophidae)、茧蜂科(Braconidae)和瘿蜂科(Cynipidae)共计3科9属16种,分别为双斑潜蝇姬小蜂Diglyphus bimaculatus, 豌豆潜蝇姬小蜂Diglyphus isaea, 小斑潜蝇姬小蜂Diglyphus minoeus, 万氏潜蝇姬小蜂Diglyphus wani, Diglyphus sp., 纵纹瑟姬小蜂Cirrospilus vittatus, Hemiptarsenus sp., 芙新姬小蜂Neochrysocharis formosa, 底比斯姬小蜂Chrysocharis pentheus, 普金姬小蜂Chrysocharis pubicornis, Chrysocharis sp., 潜蝇柄腹姬小蜂Pediobius metallicus, Pnigalio sp., 西伯利亚离颚茧蜂Dacnusa sibirica, Dacnusa sp.和Gronotoma sp.;其中优势种为西伯利亚离颚茧蜂、双斑潜蝇姬小蜂和豌豆潜蝇姬小蜂,其个体数量占比分别为总采集个体数的48.7%, 22.1%和12.9%。【结论】西藏南美斑潜蝇的寄生蜂种类丰富,发挥着重要的自然控制作用。建议进一步加强优势寄生蜂生物学、控害潜力评价以及利用研究,为南美斑潜蝇的绿色防控提供指导。     

南美斑潜蝇的寄主植物种类及其嗜食性

斑潜蝇属双翅目 (Ｄｉｐｔｅｒａ)潜蝇科 (Ａｇｒｏｍｙｚｉｄａｅ)斑潜蝇属 (Ｌｉｒｉｏｍｙｚａ)。世界上已知有 30 0多种 ,其中对经济具有重要性的、多食性的种类有 10种 ,而对作物危害最严重的有 3种 :美洲斑潜蝇Ｌ .ｓａｔｉｖａｅ、南美斑潜蝇Ｌ .ｈｕｉｄｏｂｒｅｎｓｉｓ和三叶斑潜蝇Ｌ .ｔｒｉｆｏｌｉｉ[1,2 ] 。1992年、 1994年分别在云南元谋县热区蔬菜和嵩明县杨林镇的菊花、洋桔梗上查获美洲斑潜蝇和南美斑潜蝇[3] 。一般造成的经济损失均在 30 %以上 ,并且有继续蔓延危害的趋势。南美斑潜蝇已遍及全省及我国的8省 1市[4 ] 。…     

温、湿度对南美斑潜蝇和美洲斑潜蝇羽化的影响

在实验条件下 ,研究了温湿度对南美斑潜蝇Liriomgzahuidobrensis和美洲斑潜蝇Liriomgzasativae羽化的影响。结果表明 ,温度对 2种斑潜蝇日羽化节律有显著的影响。随温度的升高 ,成虫的日羽化时段相应缩短 ,日羽化高峰期相应提前。且 2种斑潜蝇的羽化均集中在 1 2 :0 0之前。 2种斑潜蝇羽化所需要的最适温度 :南美斑潜蝇为 2 0℃ ,美洲斑潜蝇为 2 5℃ ;羽化所需要的最适相对湿度 :南美斑潜蝇为90 % ,美洲斑潜蝇为 1 0 0 %。     

曲纹紫灰蝶指名亚种的生物学特性及防治

曲纹紫灰蝶指名亚种Chilades pandava pandava(Horsfield),在广西贺州市1年发生5代,世代重叠,每代历期:1～4代30～31d,越冬代234d,以第5代蛹于11月上旬越冬,翌年6月中旬成虫出现,下旬第1代幼虫开始为害。幼虫5龄。防治方法以营林措施为主。其危害苏铁情况以及形态特征和生物学特性作了描述。     

淡剑袭夜蛾生物学特性观察

淡剑袭夜蛾是草坪的主要害虫之一。在天津市1年发生4～5代,以第四、五代老熟幼虫在草皮下越冬,翌年4月上旬至10月上旬为发生危害期。记述了该虫的形态特征、生活年史、发育历期、生活习性及天敌情况,并提出了防治建议。     

南美斑潜蝇蛹期的生物学特性

南美斑潜蝇Liriomyzahuidobrensis在 1 5 ,2 0 ,2 5 ,30 ,35℃时 ,其蛹的历期分别为 34 5 ,1 5 8,1 0 1 ,7 2d ,而在 35℃时则不能正常羽化。土壤相对含水量为 30 %～ 90 %均比较适合南美斑潜蝇蛹的发育 ,就死亡率而言 ,它们之间没有显著差异。浸水处理表明 ,南美斑潜蝇的预蛹及蛹的初期和末期对浸水比较敏感 ,死亡率均达到 90 %以上 ,而处于中间期的蛹对浸水相对不敏感。田间调查和室内饲养均发现 ,南美斑潜蝇在 1 2时以前的化蛹个数占 1d总化蛹个数的 90 %以上 ,而 1 4时以前的羽化数占 1d总羽化数的 99%以上。南美斑潜蝇化蛹的场所在不同时期不同的蔬菜上有所不同 ,越冬时主要是以蛹在越冬寄主田的土壤中越冬 ,在生长季节 ,除了在菜豆的叶片反面化蛹外 ,其它蔬菜上则是在土壤和下部叶鞘上化蛹。     

葱斑潜蝇的生物学特性

葱斑潜蝇 1年发生 4～ 5代 ,世代重叠严重。以蛹在土中越冬 ,翌年 5月初越冬蛹羽化 ,5月上旬越冬代成虫开始产卵。室内自然变温饲养 ,得到全世代的发育起始温度为 10 .34℃ ,有效积温为 2 57.2 5日度。该虫主要以幼虫潜食叶肉造成危害。周年发生 ,呈春、秋季两个高峰 ,以春季为重。田间天敌主要是潜蝇姬小蜂 Diglyphus sp.、稀网姬小蜂 Euplectrus sp.以及金小蜂科 Pteromalidae中的一种寄生蜂 ,均为幼虫寄生。     

甘肃白银地区潜叶蝇及其寄生蜂的组成和发生调查

【目的】明确严重危害甘肃省白银地区作物的潜叶蝇及天敌寄生蜂的多样性和种群组成。【方法】采用五点取样法田间调查潜叶蝇危害的蔬菜、花卉、杂草并采样,室内对潜叶蝇及其寄生蜂进行形态鉴定和分子鉴定。【结果】在2016-2020年在甘肃白银地区采集的样本中发现6种常见潜叶蝇,包括本地种豌豆彩潜蝇Chromatomyia horticola和葱斑潜蝇Liriomyza chinensis,入侵种南美斑潜蝇L. huidobrensis、三叶草斑潜蝇L. trifolii、番茄斑潜蝇L. bryoniae和美洲斑潜蝇L. sativae。其中,豌豆彩潜蝇为优势种,可危害多科寄主植物;葱斑潜蝇仅在大葱上发现危害;南美斑潜蝇在温室内的蔬菜上发生严重;三叶草斑潜蝇首次在白银市发现;番茄斑潜蝇与美洲斑潜蝇的危害相对较轻。此外,调查的潜叶蝇寄生蜂包括3科12属24种,优势种包括豌豆潜蝇姬小蜂Diglyphus isaea、芙新姬小蜂Neochrysocharis formosa、万氏潜蝇姬小蜂D. wani和西伯利亚离颚茧蜂Dacnusa sibirica。【结论】一方面白银市应加强监测和预警入侵性潜叶蝇的发生,另一方面白银市潜叶蝇的天敌寄生蜂种类丰富,对田间主要危害的潜叶蝇可能发挥着重要的自然防控作用,建议保护利用本地寄生蜂天敌。     

棉小造桥虫发生规律的初步分析

棉小造桥虫在山东临清县一年一般发生三代。7月上旬第一代开始发生,该代密度小,危害很轻。8月上旬—9月上旬为第二代至第三代发生期,这两代虫的密度大,危害较重,尤以第二代发生最重。第三代有时也暴发成灾。 根据1960年—1964年五年的调查资料分析,棉小造桥虫发生程度的轻重与气象因素有密切关系。第一代一般发生很轻,积累资料较少。第二代、第三代发生程度和气温、相对湿度、降雨量的关系是: 1.7月中、下旬两旬平均相对湿度大,气温高,第二代造桥虫发生较重(表1)。     

南美斑潜蝇为害对黄瓜体内主要营养物质、 次生代谢物质及叶绿素含量的影响

南美斑潜蝇Liriomyza huidobrensis (Blanchard)是一种危害多种蔬菜和观赏植物的多食性害虫。本研究采用蒽酮比色法、 考马斯亮蓝法、 磷钼酸 磷钨酸比色法、 索氏回流法及丙酮法, 分别测定了南美斑潜蝇1~3龄幼虫不同为害程度（系统受害、 轻度受害和重度受害）对黄瓜叶片内可溶性糖、 可溶性蛋白质、 单宁、 黄酮及叶绿素含量的影响。结果表明： 南美斑潜蝇幼虫为害后, 黄瓜叶片中可溶性糖、 可溶性蛋白质和叶绿素的含量随着为害程度的增强而显著降低（P<0.01）, 最大降幅分别为62%, 35%和40%; 单宁和黄酮的含量随着为害程度的增强而显著上升（P<0.01）, 最高升幅分别为26%和53%; 并且具有系统性影响。结果提示, 南美斑潜蝇幼虫为害导致寄主植物营养物质含量下降、 光合作用降低, 而次生代谢物质含量上升, 从而对植食者产生诱导抗性。本研究结果为进一步揭示南美斑潜蝇与其寄主植物相互作用关系及其机理提供了有益的参考。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.