New Records of Korean Whiteflies (Hemiptera: Aleyrodidae)

Four aleyrodid species, Aleuroclava montanus (Takahashi), Asterobemisia atraphaxius (Danzig), Pentaleyrodes yasumatsui Takahashi, and Rhachisphora styraci (Takahashi) are newly recorded in the Korean fauna of whiteflies (Aleyrodidae).     

The whiteflies (Hemiptera: Aleyrodidae) of Europe and the Mediterranean Basin

The whitefly fauna of Europe and the Mediterranean Basin comprises 56 species that are considered to be native or naturalized, accommodated within 25 genera. Presented here are a check-list, an identification key to puparia, and a brief account of each species including its distribution and host-plant range. The puparium of each species is illustrated. One new nomenclatural combination (Aleuroclava similis, from Aleurotuberculatus) and two new synonymies (Parudamoselis kesselyaki with Ceraleurodicus varus, Asterobemisia nigrini with A. paveli) are proposed. Three nominal species (Aleurodes capreae, A. fraxini, and Aleyrodes campanulae) are here treated as nomina dubia. Species which, in the study area, have only been recorded from glasshouses are discussed. Four additional species, not yet recorded from the region, are included in the discussion, two of them because a particular quarantine risk is perceived and two because they are notifiable pests in European Union quarantine legislation.     

烟粉虱(Bemisia tabaci)的寄主选择性

通过田间系统调查、实验室嗅觉测定、笼内和培养皿内自由扩散观察,对烟粉虱的寄主选择性进行了研究.结果表明,在田间,烟粉虱对不同的寄主植物存在明显的寄主选择性,其中对茄子、花椰菜、黄瓜等植物具有较强的嗜性,而对蕹菜、芹菜、苋菜等植物的嗜性较差;烟粉虱对同一植物的不同品种也有明显的选择性.烟粉虱对寄主植物颜色有明显的选择性,选择结果与烟粉虱对这些寄主的嗜性趋势基本一致.烟粉虱对单株寄主植物的嗅觉反应不敏感,但对植物叶片的乙醇抽提物有明显的嗅觉反应,并表现出较强的寄主选择性.在养虫笼内,烟粉虱从虫源皿向寄主植物自由扩散的过程中,在不同寄主植物和同一植物的不同品种上着落的成虫数量不同,并且在一定的时间范围内,着落在寄主叶片上的虫量还会不断的发生变化.     

Isolation and characterization of microsatellite loci in Bemisia tabaci (Hemiptera: Aleyrodidae)

Microsatellite‐enriched genomic libraries were obtained from the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) using a magnetic/biotin capture of repetitive sequences. Ten dinucleotide markers were successfully isolated and characterized from these libraries. Variability was assessed in six populations of B. tabaci collected from different localities of the island of Crete, Greece. The number of alleles per locus in approximately 105 individuals screened across populations ranged from two to 13. Averaged observed heterozygosity over the six populations ranged from 0.001 to 0.58.     

内共生菌Cardinium对烟粉虱MED隐种耐药性的影响

【目的】次生内共生菌感染可影响烟粉虱Bemisia tabaci对杀虫剂的敏感性。本研究旨在揭示内共生菌Cardinium感染对烟粉虱B. tabaci MED隐种耐药性的影响。【方法】室内测定海南陵水与山东寿光烟粉虱MED隐种种群内遗传背景一致的Cardinium感染与未感染品系对不同浓度新烟碱类杀虫剂噻虫嗪和吡虫啉的耐药性。【结果】各浓度噻虫嗪和吡虫啉处理后,烟粉虱陵水种群感染Cardinium品系死亡率比未感染品系显著降低;100, 150, 175和200 mg/L噻虫嗪以及175和200 mg/L吡虫啉处理后,烟粉虱寿光种群感染Cardinium品系死亡率比未感染品系显著上升。相对于未感染品系,烟粉虱陵水种群感染Cardinium品系对噻虫嗪、吡虫啉的抗性倍数(RR)分别是1.355和1.847,烟粉虱寿光种群感染Cardinium品系的RR分别是0.790和0.847。【结论】内共生菌Cardinium感染能影响烟粉虱MED隐种对噻虫嗪和吡虫啉的耐药性,且这种影响在不同种群间存在差异。研究结果对于揭示烟粉虱MED隐种的种群适应性及扩张机制具有重要参考价值。     

Functional response of Nesidiocoris tenuis (Hemiptera: Miridae) to Trialeurodes vaporariorum (Hemiptera: Aleyrodidae): effect of different host plants

The influence of three host plants, namely cucumber, tomato and eggplant, on functional response of male, virgin and mated female predatory bug Nesidiocoris tenuis was investigated on different densities of Trialeurodes vaporariorum nymphs. The 24-h experiment conducted at laboratory conditions revealed that N. tenuis exhibited a type II functional response to T. vaporariorum on host plants. There were no significant differences between attack rates, as well as handling times estimated for each adult stage of the predator between host plants. However, on each host plant, the handling time estimated for the mated female in comparison with two other adult stages had lower values (0.7952, 0.6827 and 0.8884?h^?1 on cucumber, tomato and eggplant, respectively). Handling time estimated for the mated female on cucumber was significantly lower than that estimated for the male predator. The highest maximum handling rate (T/T_h) was estimated for the mated female followed by the virgin female and male on all host plants. For three adult stages of the predator, the highest value of this parameter was determined on tomato followed by cucumber and eggplant. Unlike virgin and mated females, the host plant significantly affected prey consumption by the male. Prey consumed by mated females was higher than those obtained for two other adult stages of the predator on each host plant. The difference in trichome density between three host plants may be responsible for the obtained results. These results revealed that N. tenuis is more effective in the biological control of T. vaporariorum on tomato in comparison with cucumber and eggplant.     

Diversity and evolution of the Wolbachia endosymbionts of Bemisia (Hemiptera: Aleyrodidae) whiteflies

Wolbachia is the most prevalent symbiont described in arthropods to date. Wolbachia can manipulate host reproduction, provide nutrition to insect hosts and protect insect hosts from pathogenic viruses. So far, 13 supergroups of Wolbachia have been identified. The whitefly Bemisia tabaci is a complex containing more than 28 morphologically indistinguishable cryptic species. Some cryptic species of this complex are invasive. In this study, we report a comprehensive survey of Wolbachia in B. tabaci and its relative B. afer from 1658 insects representing 54 populations across 13 provinces of China and one state of Australia. Based on the results of PCR or sequencing of the 16S rRNA gene, the overall rates of Wolbachia infection were 79.6% and 0.96% in the indigenous and invasive Bemisia whiteflies, respectively. We detected a new Wolbachia supergroup by sequencing five molecular marker genes including 16S rRNA, groEL, gltA, hcpA, and fbpA genes. Data showed that many protein‐coding genes have limitations in detecting and classifying newly identified Wolbachia supergroups and thus raise a challenge to the known Wolbachia MLST standard analysis system. Besides, the other Wolbachia strains detected from whiteflies were clustered into supergroup B. Phylogenetic trees of whitefly mitochondrial cytochrome oxidase subunit I and Wolbachia multiple sequencing typing genes were not congruent. In addition, Wolbachia was also detected outside the special bacteriocytes in two cryptic species by fluorescence in situ hybridization, indicating the horizontal transmission of Wolbachia. Our results indicate that members of Wolbachia are far from well explored.     

中国粉虱科二新纪录种记述（半翅目：粉虱科）

记述粉虱科2中国新纪录种:木姜子棒粉虱Aleuroclava ayyari(Sundararaj&David)和扁担杆褶粉虱Aleurotrachelus grewiae Takahashi。用环境扫描电镜对其伪蛹进行拍照,并依据玻片标本进行描述和绘图。木姜子棒粉虱主要鉴别特征是在头部和第1腹节分别着生1对长的亚背区刚毛。扁担杆褶粉虱主要鉴定特征是蛹壳硬化,头尾两端较尖,腹部中央基部较圆。标本存放在扬州大学昆虫标本室。     

Suitability of Aphis craccivora (Hemiptera: Aphididae) and Bemisia tabaci (Hemiptera: Aleyrodidae) biotype-B as prey for Chrysopa pallens (Neuroptera: Chrysopidae)

The suitability of Aphis craccivora Koch (Hemiptera: Aphididae) and Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biotype-B eggs and nymphs as prey for pre-imaginal development and survival, adult longevity, and fecundity of the lacewing, Chrysopa pallens (Rambur) (Neuroptera: Chrysopidae) was evaluated under laboratory conditions at 25±1°C, 50±10% RH and a photoperiod of 16 h L:8 h D. Survival of C. pallens from first instar to adult eclosion was significantly different between the larvae that fed on the two prey species. C. pallens fed on A. craccivora completed development from egg to adult emergence, but those fed on eggs and nymphs of B. tabaci could not complete development, resulting in abnormal pupae and no normal adults emerged. The net reproductive rate (R ₀), intrinsic rate of natural population increase (r _m ), finite rate of increase (λ), mean generation time (T), index of population trend (I), doubling time (DT), and gross reproductive of rate (GRR) of C. pallens that fed on A. craccivora were 201.9 eggs per female, 0.13/d, 1.1/d, 40.1 d, 68.5, 5.2 d, 203.1 eggs per female, respectively. These results could be useful for mass-rearing of C. pallens and for understanding its population dynamics in the field in relation to the availability of different prey species.     

Host plants and natural enemies of Bemisia tabaci (Hemiptera: Aleyrodidae) in China

Abstract The sweetpotato whitefly, Bemisia tabaci, has been a destructive pest in China for over the past two decades. It is an extremely polyphagous insect, being recorded feeding on hundreds of host plants around the world. Potential host plants and natural enemies of B. tabaci in the south, southeast, middle, north and northwest of China were investigated during the last decade. In total 361 plant species from 89 families were recorded in our surveys. Plants in the families Compositae, Cruciferae, Cucurbitaceae, Solanaceae and Leguminosae were the preferred host species for B. tabaci, which therefore suffered much damage from this devastating pest due to their high populations. In total, 56 species of parasitoids, 54 species of arthropod predators and seven species of entomopathogenic fungi were recorded in our surveys. Aphelinid parasitoids from Encarsia and Eretmocerus genera, lady beetles and lacewings in Coleoptera and Neuroptera were found to be the dominant arthropod predators of B. tabaci in China. The varieties of host plant, their distribution and the dominant species of natural enemies of B. tabaci in different regions of China are discussed.     

Phototactic behavior of Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae) under visible wavelengths

The greenhouse whitefly, Trialeurodes vaporariorum Westwood (Hemiptera: Aleyrodidae), is one of the most important pests of greenhouse crops. The intensive use of chemical insecticides has resulted in insecticide resistance in T. vaporariorum and the critical level of pesticides residue in crops. It is therefore necessary to develop new control methods based on ecological pest management. The present study was designed to control greenhouse whitefly by finding and using insect repellent wavelengths. The repellent wavelength experiment was conducted by a two-way phototactic apparatus given a choice between darkness and visible wavelength spectrum from violet (380–450 nm) to red (620–750 nm). The phototactic responses of the greenhouse whitefly were then investigated in a four-way phototactic apparatus given a choice between two light regimes, light-emitting diode (LED) and sunlight. The results indicated that the lowest (69.2%) and highest (97.8%) number of whiteflies were attracted to violet and orange (590–625 nm) spectra, respectively. In addition, the present study indicated a significant attraction of T. vaporariorum adults to sunlight compared with LED. Furthermore, the eggplants grown under growth LEDs showed a significantly higher growth rate than the plants grown under sunlight. These findings suggest that this type of LED not only has positive effects on plant growth but it also has a repellent activity on T. vaporariorum adults, leading us to develop an effective behavioral control of the greenhouse whitefly.     

Insecticide resistance monitoring in whitefly (Bemisia tabaci) (Hemiptera: Aleyrodidae) in Oman

The sweet potato whitefly, Bemisia tabaci Gennadius, is an important insect pest of many crops including vegetables through direct feeding damage and as a vector of several plant viruses. Intensive use of insecticides has led to the development of insecticide resistance in global B. tabaci populations. This study was conducted to establish susceptibility levels to deltamethrin, thiamethoxam and pyriproxyfen in seven geographically different populations of B. tabaci MEAM1 adults in Oman. All B. tabaci populations showed very low to low level of resistance (2.1–12.3 fold) to deltamethrin. All B. tabaci populations showed no resistance to very low level of resistance to thiamethoxam (2.2–6.2 fold) and pyriproxyfen (2.4–3.5 fold). A likelihood analysis showed the possibility for control failure in two populations (Barka and Salalah) to deltamethrin, however, no possible failure was detected in all populations for thiamethoxam and pyriproxyfen. An insecticide resistance dynamics study in one population (SQU-1) showed a loss in susceptibility to deltamethrin with increase in the LC₅₀ value from 25.1 mg L⁻¹ to 84.5 mg L⁻¹ between 2017 and 2019 resulting in 5.3 fold increase in RF. The study results determined that several B. tabaci populations are at the initial stages of resistance development to deltamethrin and cross-resistance with thiamethoxam and pyriproxyfen. Vegetable farmers in Oman, the Barka and Salalah regions in particular, should be cautious in the repeated use of one class of insecticide alone.     

Genetic Analysis of Bemisia (Hemiptera: Aleyrodidae) Populations by Isoelectric Focusing Electrophoresis

Twenty-one whitefly populations in the genus Bemisia were evaluated for genetic variation at 3 allozyme loci. Nine of the 22 populations that exhibited polymorphic loci were subjected to allozyme analysis using a minimum of 10 enzymes, representing 10 to 14 distinct loci. Among those nine variants examined, calculated genetic distances ranged between 0.03 and 0.52, with three main groups emerging from the analysis. One group comprised two closely related Western Hemisphere variants of B. tabaci: type A from California, United States and a geographically proximal population from Culiacan, Mexico. A second cluster contained five collections previously identified as B. tabaci type B and Bemisia argentifolii, while a third group contained a single population from Benin, Africa. The latter two groups were grouped separately from New World populations and are thought to have a recent origin in the Eastern Hemisphere.     

Direct and Indirect Impacts of Infestation of Tomato Plant by Myzus persicae (Hemiptera: Aphididae) on Bemisia tabaci (Hemiptera: Aleyrodidae)

The impacts of infestation by the green peach aphid (Myzus persicae) on sweetpotato whitefly (Bemisia tabaci) settling on tomato were determined in seven separate experiments with whole plants and with detached leaves through manipulation of four factors: durations of aphid infestation, density of aphids, intervals between aphid removal after different durations of infestation and the time of whitefly release, and leaf positions on the plants. The results demonstrated that B. tabaci preferred to settle on the plant leaves that had not been infested by aphids when they had a choice. The plant leaves on which aphids were still present (direct effect) had fewer whiteflies than those previously infested by aphids (indirect effect). The whiteflies were able to settle on the plant which aphids had previously infested, and also could settle on leaves with aphids if no uninfested plants were available. Tests of direct factors revealed that duration of aphid infestation had a stronger effect on whitefly landing preference than aphid density; whitefly preference was the least when 20 aphids fed on the leaves for 72 h. Tests of indirect effects revealed that the major factor that affected whitefly preference for a host plant was the interval between the time of aphid removal after infestation and the time of whitefly release. The importance of the four factors that affected the induced plant defense against whiteflies can be arranged in the following order: time intervals between aphid removal and whitefly release > durations of aphid infestation > density of aphids > leaf positions on the plants. In conclusion, the density of aphid infestation and time for which they were feeding influenced the production of induced compounds by tomatoes, the whitefly responses to the plants, and reduced interspecific competition.     

Bemisia tabaci （Hemiptera： Aleyrodidae） nymphal feeding in cotton （Gossypium hirsutum） leaves

We used brightfield electron microscopy （BEM）, differential interference contrast microscopy （DICM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and confocal laser scanning microscopy （CLSM） to investigate the stylet pathways of Bemisia tabaci during nymphal feeding behavior in cotton leaves beginning with penetration of the abaxial leaf surface and ending with stylets in sieve tubes in phloem tissues. Most nymphal stylets within salivary sheaths penetrating leaf tissues made complex turns and developed more than one salivary sheath branch before ending in sieve tubes. The external morphology of the salivary sheaths and their routes between and through leaf cells are described during the present study. Results showed the presence of the stylet within the sieve tubes. B. tabaci nymphs may remove stylets and feed in different sieve tubes. Ten short movies showing the progression of the stylet penetrations from adaxial surface to the sieve tubes are attached to Figures 8-15. The report and movies can be viewed from the internet. Download the movies to a local drive in your computer first for fast upload. The movies are posted on the website http：//www.ars.usda.gov/Services/docs.htm？docid=14629. The movies can be used as a teaching aid in biology classes.     

Electrophoretic Analysis of Non-B and B-Biotype Bemisia tabaci (Gennaduis) (Hemiptera: Aleyrodidae) in Australia

B-type Bemisia tabaci were detected in Australia for the first time in October 1994. the whiteflies were distinguished from an existing non B-type strain of B. tabaci by electrophoretic analysis of naphthyl esterases in individual whiteflies. the distinctive isoenzyme profile was consistent with B-type populations from other areas of the world. Individuals heterozygous for both patterns were also detected using this technique, confirming that the B-type and Australian strain could interbreed. an Australia-wide survey showed that B-types were widely distributed in New South Wales, Queensland and the Northern Territory. the B-type was also detecte in Tasmania. the origins of the B-type and the implications for Australian agriculture, should it become an established pest on key crops, are discussed.     

浙江地区梨树上粉虱类害虫种类初记

为摸清浙江地区梨树上粉虱类害虫种类,通过采集梨树上的粉虱伪蛹制作玻片标本后进行观察鉴定.通过形态学研究,共鉴定出梨树粉虱6属、8种,其中梨树寄主新记录种6种,分别为马氏粉虱Aleurolobus marlatti(Quaintance)、杨梅粉虱Parabemisia myricae(Kuwana)、番石榴白棒粉虱Al...