性诱剂和黄板对设施蔬菜烟粉虱诱集效果的比较

【背景】烟粉虱是设施茄果类蔬菜上的重要害虫。【方法】在温室辣椒和黄瓜田中,研究3种方式(悬挂性诱剂、黄板和性诱剂+黄板)对烟粉虱的诱集作用。【结果】性诱剂和黄板对烟粉虱均有较好的诱杀效果,在黄瓜田悬挂性诱剂和黄板4 h后,性诱剂、黄板、性诱剂+黄板上分别诱集到烟粉虱成虫13.80、7.40和31.20头;随着悬挂时间的延长,诱虫量逐渐增多,悬挂24 h后,3种方式的诱集量分别达到32.20、31.80和52.80头。在48 h以内,性诱剂诱虫量明显多于黄板,但48 h后黄板上的诱集量明显多于性诱剂。对黄瓜上残留成虫的性比调查发现,诱集处理24 h后,悬挂性诱剂和性诱剂+黄板的黄瓜上烟粉虱性比分别为4.05∶1和3.31∶1,而悬挂黄板的黄瓜上烟粉虱性比接近1∶1。不论是性诱剂还是黄板,1 d中以10:00~14:00之间对烟粉虱的诱集量最大。性诱剂不同悬挂高度对烟粉虱的诱集效果不同,在辣椒田,性诱剂白板的下端与辣椒顶部冠层叶相平时对烟粉虱的诱集量显著多于白板下端高出辣椒顶部冠层叶上部10 cm与50 cm的处理。诱集处理4 d后,性诱剂、黄板和性诱剂+黄板对蔬菜烟粉虱的校正防效分别为68.18%、60.42%和77.40%。【结论与意义】性诱剂对烟粉虱雄虫有强烈的专性诱集作用,黄板和性诱剂联用对烟粉虱的诱集具有明显的增效作用。     

设施黄瓜烟粉虱的区域生态防控研究

烟粉虱是设施蔬菜上的重要害虫。为探讨烟粉虱的可持续控制方法,在蔬菜试验基地,通过虫源清理、黄板诱杀、诱集剂诱杀和芹菜间作驱虫等综合措施,研究非化学措施对黄瓜烟粉虱的持续控制作用。结果表明:在烟粉虱扩散迁移阶段,虫源的距离与成虫向大棚的迁入量呈负相关,虫源虫量与迁入量呈正相关;虫源扰动对烟粉虱迁入具有促进作用;烟粉虱在扩散过程中对新寄主仍遵循就近选择的原则;对黄板的选择性明显高于黄瓜,两者之间的虫量比在7.91∶1~420.00∶1;在棚内使用黄板加引诱剂及黄板加芹菜对黄瓜上的烟粉虱均具有较好的控制作用,虫口减退率均达到90%以上。结果表明,区域生态防控是对烟粉虱进行可持续绿色控制的有效方式。     

黄色诱虫板对稻飞虱的诱集和防治效果

【目的】评价黄色诱虫板对稻飞虱的控制作用,为稻飞虱的非化学防控提供科学依据。【方法】在田间悬挂黄色诱虫板,调查稻飞虱的诱集情况,并同盘拍结果进行比较。【结果】上海水稻白背飞虱Sogatella furcifera(Horváth)成虫的发生高峰期集中在8月下旬;而灰飞虱Laodelphax striatellus(Fallén)和褐飞虱Nilaparvata lugens(St?l)成虫发生高峰期主要集中在9月中旬。从3种稻飞虱成虫的发生动态来看,灰飞虱发生最为严重,黄色诱虫板最高诱集数为(6.12±4.50)头/(天·板),每板每天平均诱集成虫数大于等于2头的有18个水稻品种,其余6个水稻品种诱集的成虫数虽然少于2头,但是都能诱集到成虫;其次是白背飞虱,最高诱集数为(2.29±0.13)头/(天·板),每板每天平均诱集成虫数大于等于1头的有7个水稻品种,其余17个水稻品种诱集的成虫数虽然少于1头,但是都能诱集到成虫;再次是褐飞虱,最高诱集数为(1.50±1.85)头/(天·板),每板每天平均诱集成虫数大于等于1头的有1个水稻品种,其余23个水稻品种诱集的成虫数均少于1头,其中3个水稻品种在10月中旬均没有诱集到1头成虫。总体而言,黄色诱虫板对3种稻飞虱的最高诱集数为(7.50±4.36)头/(天·板),每板每天平均诱集成虫数大于等于2头的有23个水稻品种,仅1个水稻品种诱集的成虫数少于2头。黄色诱虫板下部离水稻冠层越近,诱集的成虫越多。【结论】黄色诱虫板对稻飞虱成虫具有较好的诱杀效果,可有效降低成虫种群数量。作为一种非化学防控方法,黄色诱虫板的使用可有效降低化学杀虫剂的使用量。     

黄板诱杀黄曲条跳甲的关键技术研究

为了研究黄板不同悬挂高度、间距和尺寸规格对诱杀黄曲条跳甲的影响,本试验设置了3个不同悬挂高度(黄板下边缘距地的悬挂高度分别为:10 cm、15 cm、20 cm);3个不同悬挂间距(黄板悬挂间距3 m、6 m、9 m);3个不同规格大小(黄板长×宽为20 cm×15 cm,25 cm×20 cm,30 cm×20 cm)。结果表明:黄板悬挂时其下边缘距离地面15 cm诱虫效果最好,平均诱集75.8头/(板·d);黄板悬挂间距为6 m时,诱虫量最多,每板平均诱虫量为62.1头/(板·d);黄板大小为30 cm×20 cm时,诱虫量最大,平均每板诱集83.5头/(板·d)。从单位面积诱虫量分析,黄板大小为20 cm×15 cm时,单位面积内的诱虫量最大,为1 643.3头/m^2。因此,利用黄板诱杀甘蓝上的黄曲条跳甲,建议悬挂高度为黄板下边缘距离地面15 cm,黄板挂板间距为6 m,黄板尺寸大小为25 cm×20 cm。     

利用黄板监测烟粉虱及其寄生蜂的种群动态

研究了黄板不同放置高度、不同时间内对日光棚室内番茄上烟粉虱Bemisia tabaci(Gennadius)及其寄生蜂种群的诱集监测效果。结果表明,在同一时间内以黄板上部与植株顶部持平的高度悬挂的黄板对烟粉虱和蚜小蜂的诱集效果最好,其次是以黄板上部与植株中部持平的高度悬挂的黄板,当黄板的底部高出植株顶部30 cm时对烟粉虱及其蚜小蜂的诱集效果最差。在5~10月份,随着季节的变化,同一位置的黄板对烟粉虱及蚜小蜂的诱集数量逐渐增加。调查发现,番茄上烟粉虱的寄生蜂主要为桨角蚜小蜂属EretmocerusHaldeman和恩蚜小蜂属EncarsiaF erster,2个属的蚜小蜂在季节上呈互补之势,因此总体上蚜小蜂对烟粉虱的寄生率在5~10月之间呈不断上升的趋势。     

寄主种类、距离和种群密度对烟粉虱扩散的影响

在笼罩条件下,分别以黄瓜、棉花、蕹菜为虫源寄主和诱集寄主,研究寄主植物、空间距离、虫源密度等因子对B型烟粉虱扩散的影响。结果发现,从虫源寄主上扩散的成虫量,与烟粉虱对诱集寄主和虫源寄主的嗜性差异程度有关,诱集寄主相对于虫源寄主的嗜性越强,扩散出来的成虫数量就越多,反之扩散的成虫数量就越少。成虫扩散量与诱集寄主的距离呈负相关,并且诱集寄主的嗜性越强,随着距离的增大,诱集量下降的速率越快。成虫扩散量与虫源种群密度呈正关,但非嗜好寄主上的虫口承载量相对较低,在虫口密度相对较高时,非嗜好寄主上烟粉虱向外扩散的相对量更大。烟粉虱的扩散量与寄主营养状况呈负相关,寄主营养胁迫时,非嗜好寄主上可以获得相对更高的诱集量。     

蓝光对保护地蔬菜烟粉虱的控制作用

[目的]研究蓝光开灯时段、蓝光光强对烟粉虱Bemisia tabaci (Gennadius)的驱避作用,以及蓝光照射对保护地辣椒和黄瓜上烟粉虱的控制作用,为利用驱虫灯实施对蔬菜烟粉虱的绿色防控提供科学依据.[方法]在蔬菜上用蓝光(波长为470 nm)照射,设置照射时间段17:00-18:00、18:00-19:00、19:00-20:00、20:00-21:00和21:00-22:005个处理、光照强度1、2、6、8、10、20、30、70、1501x9个处理,分别研究不同开灯时段和光强对烟粉虱的驱避作用,以不用蓝光处理为对照;分别在保护地黄瓜和辣椒上放置蓝色灯带,每天18:00-20:00开灯,每3d一次,分别调查黄瓜和辣椒上烟粉虱的虫量.[结果]18:00-19:00时间段蓝光照射对蔬菜烟粉虱的驱避作用最强,虫口减退率占试验总时段的50.94％;17:00-18:00次之,占22.29％;烟粉虱的虫口减退率与光照强度呈正相关(P＜0.05),其回归方程为)y=3.0297x+ 12.508 (R2=0.981).蓝光对保护地辣椒和黄瓜上烟粉虱有较好的驱避作用,辣椒上蓝光处理10d后烟粉虱的虫口减退率达到85.73％,上部叶片和中部叶片上虫口减退率之间没有显著差异(P＞0.05);蓝光处理黄瓜12d后烟粉虱的虫口减退率达90.33％,在光照的前期上部叶片的虫口减退率高于中部叶片,处理9d后上部叶片和中部叶片上虫口减退率之间没有显著差异(P＞0.05).[结论]蓝光对蔬菜烟粉虱具有较强的驱避作用,在18:00-19:00使用蓝光对保护地蔬菜上的烟粉虱的控制效果较好.     

烟粉虱对四种蔬菜寄主的选择性

为探讨利用趋避作用防治烟粉虱的可能性,进行了3方面试验：1）烟粉虱Bemisia tabaci (Gennadius) 对黄瓜、花椰菜、油菜和莴苣等4种蔬菜的寄主选择性; 2）互喷烟粉虱不同嗜好的寄主植物汁液对其寄主选择性的影响; 3）不同间作方式对黄瓜叶上烟粉虱成虫密度的影响。结果表明,烟粉虱对供试植物有明显的选择性,其嗜好程度为花椰菜>黄瓜>油菜>莴苣。喷施莴苣和花椰菜汁液对烟粉虱的寄主选择性均有显著影响,喷施莴苣原液后,花椰菜和黄瓜上的成虫数分别减少79.6%和87.4%,花椰菜上的着卵量减少84.3%;喷施花椰菜原液后,莴苣上的成虫数和着卵量分别增加82.4%和79.2%,表明不同蔬菜中的内含物是引起烟粉虱对寄主选择性的重要原因。在黄瓜中间作莴苣可使黄瓜叶上烟粉虱成虫数平均减少76.5%;间作花椰菜时,通过诱集作用,也可使黄瓜叶上的成虫数平均降低69.7%。这些结果为利用喷施蔬菜汁液和间作方式控制烟粉虱危害提供了理论依据。     

寄主植物对B型烟粉虱选择行为和生物学参数的影响

通过培养皿内自由扩散观察和生物学观察,对黄瓜、茄子、辣椒、棉花和甘薯上B型烟粉虱的寄主选择性和生物学参数进行了研究.结果表明：B型烟粉虱成虫向寄主植物叶片自由扩散的初始阶段（2 h）,各寄主植物叶片上虫量的差异不大,在随后的4～48 h内黄瓜叶片上的虫量不断增加,茄子、棉花和甘薯叶片上的虫量相对稳定,而辣椒叶片上的虫量却不断下降,说明B型烟粉虱对黄瓜的选择性最强、对辣椒的选择性最弱,且饥饿和吡虫啉预处理均不影响B型烟粉虱的寄主选择性;取食不同寄主植物烟粉虱成虫的蜜露分泌量差异显著,从高到低依次为黄瓜、甘薯、棉花、茄子、辣椒;黄瓜、茄子、甘薯、棉花上烟粉虱成虫的寿命显著长于辣椒,其平均单雌产卵量(分别为224.33粒、182.33粒、191.73粒和172.60粒)也均显著高于辣椒(47.83粒);各寄主植物上烟粉虱卵的孵化率和发育历期差异均不显著;烟粉虱若虫在黄瓜、茄子、甘薯和棉花上的发育历期分别为10.60 d、11.96 d、11.11 d和13.20 d,死亡率分别为5.21%、27.78%、17.24%和37.11%,在辣椒上不能完成正常发育.     

烟粉虱体内营养物质对寄主植物多代诱导的响应

比较同一遗传背景的B型烟粉虱Bemisia tabaci Gennadius种群成虫在甘蓝、黄瓜和一品红上的适合度差异,测定3种寄主植物主要营养差异,并分析饲养不同时间后成虫体内的蛋白质、氨基酸和游离脂肪酸含量的多代变化规律。结果发现,B型烟粉虱成虫在黄瓜上的相对适合度最高,其次是甘蓝,在一品红上适合度最低,这可能与黄瓜叶片的总氮含量高和总糖含量低有关。饲养时间对烟粉虱体内主要营养物质含量没有显著影响,但寄主植物对烟粉虱成虫体内主要营养物质含量影响显著。在黄瓜上饲养烟粉虱成虫体内蛋白质含量都显著高于一品红和甘蓝上烟粉虱成虫的蛋白质含量,在黄瓜上饲养烟粉虱成虫总氨基酸含量都显著低于一品红和甘蓝上烟粉虱成虫的总氨基酸含量。相反,在3种寄主上饲养烟粉虱成虫游离脂肪酸含量都无显著差异。可见,寄主植物对B型烟粉虱体内主要营养物质组成影响显著,但饲养时间对B型烟粉虱体内主要营养物质组成影响较小。     

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.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.