烟粉虱发与防治技术

1 烟粉虱概述 烟粉虱Bemisia tabaci(Gennadius)属同翅目,粉虱科,小粉虱属.首先报道于1889年,在希腊的烟草上发现,命名为烟粉虱.1894年,在美国的佛罗里达州的甘薯上发现了新北区的第一头烟粉虱,被鉴定为甘薯粉虱Bemisia inconspicua.烟粉虱由于其形态的变异性,产生了许多同物异名.在1957年,Russell对酷似Bemisia标本进行进一步确认,B.tabaci的异名种已达19种.到1978年烟粉虱的同物异名又达到了22种.因此,B.tabaci有几种常用俗名,如烟粉虱、棉粉虱或甘薯粉虱.     

入侵害虫螺旋粉虱的田间种群动态及其对本地节肢动物群落的影响

采用随机取样法,调查海南海口地区洋紫荆和番石榴2种螺旋粉虱寄主,记录2种寄主上螺旋粉虱种群动态、受螺旋粉虱危害植株与未受害植株上的节肢动物群落种群及数量,探讨螺旋粉虱种群波动对受害寄主植株上的节肢动物群落种类及数量变动关系。结果表明:(1)螺旋粉虱在海南为害高峰期为4月～9月份,以及11月份;(2)本地螺旋粉虱天敌数量较少,未能对螺旋粉虱达到有效控制;(3)螺旋粉虱的种群波动,不会直接导致受害寄主植株上的节肢动物群落结构的变化;(4)受害与未受害寄主植株上的植食性昆虫年发生量差异显著。     

寄主植物对螺旋粉虱发育和繁殖的影响

了解螺旋粉虱在海南几种重要寄主植物上的生物学习性,为其防控提供预警,同时可筛选出适宜的扩繁寄主.以香蕉、印度紫檀、榄仁树、木薯、木瓜、番石榴及辣椒等7种植物为寄主,在温度16～29℃、相对湿度65 ％～91％的隔离大棚中观察螺旋粉虱的发育、存活、繁殖和虫体大小等情况.结果表明:螺旋粉虱由卵至成虫的发育时间以在木薯上最短,为41.33 d;其次为番石榴及辣椒,分别为42.28、42.44 d;香蕉上的发育历期最长,为56.31 d.卵至成虫存活率以在辣椒上最高,为20.00％;木薯上最低,为3.64％.平均产卵量以在辣椒上最多,为117.63粒;香蕉上最少,为73.44粒.种群趋势指数在辣椒上最大,为12.323 1;木薯上最小为1.710 3.综合比较可知,辣椒是螺旋粉虱种群生长发育和繁殖最适宜的寄主,其次为番石榴.     

螺旋粉虱体内共生菌的研究

采用变性梯度凝胶电泳技术[denaturing gradient gel electrophoresis（DGGE）]、16S rDNA文库构建技术,以及使用Wolbachia菌特异引物研究在不同寄主上取食繁殖的螺旋粉虱自然种群体内共生菌。结果显示,在不同寄主植物取食的新入侵螺旋粉虱体内共生菌均稳定存在有初级共生菌（Candidatus Portiera aleyrodidarum）,属于变形菌门（Proteobacteria）,γ-变形菌纲,共生菌多样性较少;研究同时发现取食不同寄主植物的螺旋粉虱个体间共生菌群落多样性有一定差异,一些螺旋粉虱个体内还生存有葡萄球菌（Staphylococcus sp.）;此外,研究还发现新入侵的螺旋粉虱体内尚未检测到Wolbachia菌。表明取食不同寄主的螺旋粉虱体内均稳定存在有共生菌,同时取食不同的寄主其共生菌群落也会发生变化;Wolbachia菌尚未在新入侵海南的螺旋粉虱中建立共生关系。     

群落结构的影响研究

采用随机取样法,调查受螺旋粉虱为害的2种寄主植物上节肢动物群落结构,以探讨螺旋粉虱为害对寄主植物上节肢动物群落结构的影响。结果表明:2种寄主中,受螺旋粉虱为害的植株,节肢动物发生量明显高于未受害植株,并且主要以同翅目类昆虫数量增加为主;受螺旋粉虱为害的洋紫荆植株上,节肢动物群落的物种数量明显高于未受害植株,群落结构也较为复杂,受螺旋粉虱为害与未为害的番石榴植株上,物种数量也有所增加,但群落结构组成未发生较大改变;整体而言,于未受害洋紫荆植株相比,受害洋紫荆植株的物种丰富度及多样性较高、物种发生较为均匀,而番石榴植株受害与未受害植株间,群落的物种丰富度、多样性及均匀度等各指数差异不明显;未受害洋紫荆寄主的种群优势度较受害洋紫荆的种群优势度高。     

烟粉虱发生与防治技术

1烟粉虱概述烟粉虱Bemisia tabaci（Gennadius）属同翅目，粉虱科，小粉虱属。首先报道于1889年，在希腊的烟草上发现，命名为烟粉虱。1894年，在美国的佛罗里达州的甘薯上发现了新北区的第一头烟粉虱，被鉴定为甘薯粉虱Bemisia inconspicua。烟粉虱由于其形态的变异性，产生了许多同物异名。在1957年，Russell对酷似Bemisia玩标本进行进一步确认，B．tabaci的异名种已达19种。     

不同地区烟粉虱对几种杀虫剂相对抗药性测定

烟粉虱(Bemisia tabaci)又称棉粉虱,属同翅目粉虱科、小粉虱属,是一种多食性的小型昆虫.烟粉虱为刺吸式口器害虫,在棉花上主要吸食棉花叶片汁液,大量消耗棉花同化产物,导致棉株衰弱,严重时甚至可使植株死亡,造成棉花大幅度减产.近年来,B型烟粉虱的侵入及其对环境条件的良好适应性,导致其种群在我国迅速增加和蔓延,危害日趋严重.     

棉粉虱的发生与防治

棉粉虱[Bemisia tobaci(Gennius)]又叫烟粉虱、甘薯粉虱,谷称"小白蛾子",属同翅目,粉虱科,小粉虱属,广泛分布于世界各地.     

几种植物源杀虫剂对螺旋粉虱的生物活性及田间防治效果

采用室内生物测定和大田药效试验等方法,测定印楝素、苦参碱和烟碱对螺旋粉虱的室内生物活性与田间防治效果.结果表明,这3种杀虫剂均对螺旋粉虱具有较高的生物活性.其中在对螺旋粉虱成虫的毒力测定中,印楝素、苦参碱和烟碱LC_(50)值分别为0.0998、0.013 3、0.0023mg/L,对3龄若虫的LC_(50)值分别为1.6724、0.0593、0.031 5mg/L,对卵的LC_(50)值分别为1.2117、0.0340和0.011 3mg/L.大田药效结果表明,3种植物源杀虫剂对螺旋粉虱均有很好的防治效果和持效性,其中在1.00 mg/L的浓度下,药后5 d的防治效果仍在80%左右.     

烟粉虱在不同棉花品种上的发生数量和空间分布特点

烟粉虱是近年来入侵我国的外来有害生物之一 ,属同翅目 ,粉虱科 ,小粉虱属。有 A、B两种生物型 ,其中 B型烟粉虱的食性杂 ,寄主范围广 ,是棉花、蔬菜和花卉的主要害虫。国内自 1 997年在广东局部地区发生危害以来 ,短短的几年时间内 ,就在全国各产棉区迅速蔓延危害棉花 ,对棉花生产已构成严重威胁 ,故尽快研究出有效防治技术措施应对 ,是控制烟粉虱危害亟待解决的大问题。为探索利用棉花本身对烟粉虱的抗 (耐 )性、减轻对棉花危害程度的可能性及怎样施药可以提高防治效果 ,于 2 0 0 3年对烟粉虱在不同品种棉花上的发生数量和分布进行了调…     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).