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Bemisia tabaci Middle East-Asia Minor 1 (MEAM1) is a significant pest that damages a wide range of high-value vegetable crops in south Florida. This pest has demonstrated the ability to develop resistance to various insecticide groups worldwide. Monitoring the resistance levels of MEAM1 populations and maintaining baseline susceptibility data are crucial for the long-term effectiveness of insecticide management strategies. We conducted serial dilution bioassays on 15 field populations of MEAM1 collected in south Florida to assess their resistance to 4 key insecticides: afidopyropen, cyantraniliprole, dinotefuran, and flupyradifurone. To quantify resistance levels, resistance ratios (RR) were generated by comparing the LC50 values of field populations to those of a known susceptible MEAM1 colony reared in the laboratory. Our findings reveal that all field-collected populations were susceptible to dinotefuran (RR 1–8) and flupyradifurone (RR 2–8). While over 80% of the populations tested were susceptible to afidopyropen (RR 1–9), 2 populations exhibited low (RR 38) and moderate resistance (RR 51), respectively. In contrast, most of the populations (57%) showed low to moderate resistance to cyantraniliprole (RR 21–78), and the remaining populations were susceptible (RR 3–10). The 2 populations with resistance to afidopyropen also exhibited moderate resistance to cyantraniliprole. Further research in this direction can aid in refining insecticide resistance management programs in Florida and other regions where B. tabaci MEAM1 is a major pest. Exploring the implications of these findings will be essential for insecticide use and integrated pest management strategies in south Florida. [ABSTRACT FROM AUTHOR]

Bemisia tabaci New World (NW) (Gennadius) (Hemiptera: Aleyrodidae), a whitefly in the B. tabaci species complex, is polyphagous on many plant species. Yet, it has been displaced, albeit not entirely, by other whitefly species. Potential causes could include issues with adaptation, feeding, and the colonization of new-hosts; however, insights that would help clarify these possibilities are lacking. Here, we sought to address these gaps by performing electropenetrography (EPG) recordings of NW whiteflies, designated "Napus" and "Rapa," reared on 2 colony hosts, Brassica napus and B. rapa , respectively. Analysis of 17 probing and pathway (pw) phase-related EPG variables revealed that the whiteflies exhibited unique probing behaviors on their respective colony hosts, with some deterrence being encountered on B. rapa. Upon switching to B. rapa and B. napus , the probing patterns of Napus and Rapa whiteflies, respectively, adapted quickly to these new-hosts to resemble that of whiteflies feeding on their colony hosts. Results for 3 of the EPG variables suggested that B. rapa 's deterrence against Napus whitefly was significant prior to the phloem phase. This also suggested that adaptation by Rapa whitefly improved its pw probing on B. rapa. Based on analysis of 24 phloem phase-related EPG variables, Napus and Rapa whiteflies performed equally well once they entered phloem phase and exhibited comparable phloem acceptability on both the colony- and new-hosts. These findings demonstrate that NW whiteflies reared on a colony host are highly adaptable to feeding on a new host despite encountering some deterrence during the nonphloem phases in B. rapa plant. [ABSTRACT FROM AUTHOR]

The Middle East Asia Minor 1 biotype of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is a greenhouse and field crop pest of global significance. The objective of this study was to assess the potential of the generalist predatory thrips, Franklinothrips vespiformis Crawford (Thysanoptera: Aeolothripidae), as a biological control agent for B. tabaci. This was achieved by determining the functional responses of F. vespiformis larvae and adults to the egg and nymphal stages of B. tabaci under laboratory conditions. Analyses consisted of 10 replicates of each predator and prey stage combination on bean leaf discs for a 24-h period. Following logistic regression analyses to determine the functional response type exhibited, response parameters were estimated with nonlinear least squares regression using Roger's equation. Results showed that F. vespiformis larvae and adults exhibited a Type II functional response when feeding on immature B. tabaci. The handling times (T h ) of F. vespiformis larvae and adults were magnitudes higher for B. tabaci nymphs than they were for eggs, which were in part driven by the higher attack rates (a) observed on eggs. The maximum attack rate (T / T h ) for B. tabaci eggs and nymphs exhibited by first-stage larvae, second-stage larvae, and adult F. vespiformis increased with increasing predator age. Results from this study suggest that F. vespiformis larvae and particularly adults are promising biological control agents for B. tabaci and are efficient predators at both low and high prey densities. [ABSTRACT FROM AUTHOR]

The sweetpotato whitefly, Bemisia tabaci (Gennadius) Middle East-Asia Minor 1 (MEAM1), is widespread across tropical and subtropical regions, affecting hundreds of cultivated and wild plant species. Because the species transmits a variety of viruses, the whitefly has become one of the most economically significant insect pests in the world. Determining a pest's population growth potential as a function of temperature is critical for understanding a species population dynamics, predicting the potential range of the species and its associated diseases, and designing adaptive pest management strategies. The life history of B. tabaci MEAM1 was studied in life-table experiments at 7 constant temperatures ranging from 12 to 35 °C. Nonlinear equations were fitted to development, mortality, and reproduction data and compiled into an overall phenology rate-summation model using Insect Life Cycle Modeling (ILCYM) software, to simulate life-table parameters based on temperature. Life tables of B. tabaci MEAM1 observed at naturally variable temperature in La Molina, Lima, during different seasons, covering the entire temperature range of the species' predicted performance curve, were used to validate the model. Simulations predicted population growth within temperature between 13.9 and 33.4 °C, revealing a maximum finite rate of population increase (λ = 1.163), with a generation time of 33.3 days at 26.4 °C. Predicted species performance agreed well when compared against observed life tables and published data. The process-based physiological model presented here for B. tabaci MEAM1 should prove useful to predict the potential spatial distribution of the species based on temperature and to adjust pest control measures taking different population growth potentials due to prevailing temperature regimes into account. [ABSTRACT FROM AUTHOR]

The whitefly, Bemisia tabaci, is a destructive and invasive pest of many horticultural plants including poinsettia (Euphorbia pulcherrima). Outbreaks of B. tabaci cause serious damage by direct feeding on phloem sap, and spreading 100+ plant viruses to crops. Bemisia tabaci were observed more frequently on green than red poinsettia leaves, and the factors responsible for this are unknown. Here, we investigated the development rate, survivorship, fecundity of B. tabaci feeding on green versus red leaves, as well as the leaves' volatiles, trichome density, anthocyanin content, soluble sugars, and free amino acids. Compared to red leaves, B. tabaci on green leaves showed increased fecundity, a higher female sex ratio, and survival rate. The green color alone was more attractive to B. tabaci than red. Red leaves of poinsettia contained more phenol, and panaginsene in their volatiles. Alpha-copaene and caryophyllene were more abundant in the volatiles of poinsettia green leaves. Leaf trichome density, soluble sugars and free amino acids were higher in green than red leaves of poinsettia, anthocyanin was lower in green than red leaves. Overall, green leaves of poinsettia were more susceptible and attractive to B. tabaci. The morphological and chemical variation between red and green leaves also differed; further investigation may reveal how these traits affect B. tabaci's responses. [ABSTRACT FROM AUTHOR]

Cytochrome P450 monooxygenases (P450s) are well-known for their crucial roles in the detoxification of xenobiotics. However, whether CYP6CX2 and CYP6CX3, 2 genes from our Bemisia tabaci (B. tabaci) MED/Q genome data were associated with detoxification metabolism and confer resistance to thiamethoxam is unclear. In this study, we investigated the role of CYP6CX2 and CYP6CX3 in mediating whitefly thiamethoxam resistance. Our results showed that mRNA levels of CYP6CX2 and CYP6CX3 were up-regulated after exposure to thiamethoxam. Transcriptional levels of 2 genes were overexpressed in laboratory and field thiamethoxam resistant strains by RT-qPCR. These results indicate that the enhanced expression of CYP6CX2 and CYP6CX3 appears to confer thiamethoxam resistance in B. tabaci. Moreover, linear regression analysis showed that the expression levels of CYP6CX2 and CYP6CX3 were positively correlated with thiamethoxam resistance levels among populations. The susceptibility of whitefly adults was markedly increased after silencing 2 genes by RNA interference (RNAi) which further confirming their major role in thiamethoxam resistance. Our findings provide information to better understand the roles of P450s in resistance to neonicotinoids and suggest that these genes may be applied to develop target genes for sustainable management tactic of agricultural pests such as B. tabaci. [ABSTRACT FROM AUTHOR]

Ferritins are conserved iron-binding proteins that exist in most living organisms and play an essential role in the maintenance of cellular iron homeostasis. Although ferritin has been studied in many species, little is known about its role in the whitefly, Bemisia tabaci. In this study, we identified an iron-binding protein from B. tabaci and named it BtabFer1. The full-length cDNA of BtabFer1 is 1,043 bp and encodes a protein consisting of 224 amino acids with a deduced molecular weight of 25.26 kDa, and phylogenetic analysis shows that BtabFer1 is conserved among Hemiptera insects. The expression levels of BtabFer1 in different developmental stages and tissues were analyzed by real-time PCR, and results showed that BtabFer1 was ubiquitously expressed at all developmental stages and in all examined tissues. The RNAi-mediated knockdown of BtabFer1 caused a significant reduction in survival rate, egg production, and egg hatching rate of whiteflies. Knockdown of BtabFer1 also inhibited the transcription of genes in the juvenile hormone signal transduction pathway. Taken together, these results suggest that BtabFer1 plays a critical role in the development and reproduction of whiteflies. This study can broaden our understanding of ferritin in insect fecundity and development, as well as provide baseline data for future studies. [ABSTRACT FROM AUTHOR]

Rugose spiraling whitefly (RSW), Aleurodicus rugioperculatus Martin, a native pest of coconut in Central America, has recently been introduced to South-East Asia. Little is known about the spread of RSW in Bangladesh, the effect this pest has on coconut plants, or the full range of its plant hosts. To fill this knowledge gap, we conducted surveys across the southern coastal coconut producing region of Bangladesh. Coconut plant damage from RSW was high throughout all the areas surveyed, and this was correlated with the population density of RSW. Areas, such as Khulna, which had the highest population density of RSW, had the highest level of RSW leaf damage. Coconut plants with an infestation of RSW had significantly fewer leaves and fruits. The coconut fruits were also smaller, both in terms of size and weight, and contained less water and lighter endosperm compared to non-infested plants. This highlights the need for the management of RSW in coconut growing regions. We also report 39 new host plant species for RSW from 22 plant families, including the economically important mangrove plant Nipa palm, Nypa fruticans Wurmb. [ABSTRACT FROM AUTHOR]

Whiteflies of the Bemisia tabaci species complex are among the most damaging insect pests in agriculture worldwide, causing damage by feeding on crop plants and by vectoring plant viruses. The species complex consists of over 35 cryptic species that differ in many aspects of their biology including the optimal environment, geographic distribution, and host range. Global warming and associated climate change resulting from human activities is expected to contribute to biological invasions. Bemisia tabaci species show fast adaptability to changes in agroecosystems and have a long record of biological invasions. Climate change driven increase in B. tabaci importance in agricultural systems of Europe has been predicted, but so far not experimentally tested. The present study evaluates the development of B. tabaci MED (=Mediterranean) in a climatic chamber simulation of the future climate in Luxembourg, chosen as a representative region for the Central Europe. Future climate predictions for the period 2061–2070 were derived from a multimodel ensemble of physically consistent regional climatic models. Results show a 40% shorter development time of this important pest in future climatic conditions, with an increase in fecundity by a third, and insignificant difference in mortality. Accelerated development, combined with its already established year-round presence in European greenhouses and predicted northward expansion of outdoor tomato production in Europe, means faster population build-up at the beginning of the outdoor cropping season with the potential of reaching economic importance. Benefits of simulating hourly diurnal cycle of physically consistent meteorological variables versus previous experiments are discussed. [ABSTRACT FROM AUTHOR]

The juvenile hormone (JH) plays a vital role in the regulation of a number of physiological processes, including development, reproduction, and ovarian maturation. Isopentenyl pyrophosphate isomerase (IPPI) is a key enzyme in the biosynthetic pathway of JH. In this study, we identified an isopentenyl pyrophosphate isomerase protein from Bemisia tabaci and named it BtabIPPI. The open reading frame (ORF) of BtabIPPI is 768 bp and encodes a protein of 255 amino acids that contains a conserved domain of the Nudix family. The temporal and spatial expression profiles showed that BtabIPPI was highly expressed in the female adults.RNA interference (RNAi)-mediated silencing of BtabIPPI reduced JH titers and the relative expression of vitellogenin receptor (VgR) and JH signaling pathway genes, resulting in a dramatic reduction in fecundity and hatchability. These results indicate that the BtabIPPI gene plays an important role in the female fecundity of B. tabaci. This study will broaden our understanding of the function of IPPI in regulating insect reproduction and provide a theoretical basis for targeting IPPI for pest control in the future. [ABSTRACT FROM AUTHOR]

The whitefly Bemisia tabaci is a piercing-sucking herbivore that reduces the yields of crops both by feeding on plants and transmitting plant viruses. Like most plant feeders, B. tabaci has evolved ways to avoid plant defence responses. For example, B. tabaci is known to secrete salivary effectors to suppress host defences. However, the nature of B. tabaci effectors is not completely understood. In this study, we used B. tabaci genomic and salivary gland transcriptomic data and an overexpression system to identify a previously unknown B. tabaci salivary effector, BtE3. BtE 3 is specifically expressed in the head (containing primary salivary glands) and is secreted into hosts during B. tabaci feeding. In planta overexpression of BtE3 blocked Burkholderia glumae -induced hypersensitive response (HR) in both Nicotiana benthamiana and Solanum lycopersicum. Silencing of BtE3 by plant-mediated RNAi prevented B. tabaci from continuously ingesting phloem sap, and reduced B. tabaci survival and fecundity. Moreover, overexpression of BtE3 in planta up-regulated the salicylic acid- (SA-) signalling pathway, but suppressed the downstream jasmonic acid- (JA-) mediated defences. Taken together, these results indicate that BtE3 is a B. tabaci -specific novel effector involved in B. tabaci -plant interactions. These findings increase our understanding of B. tabaci effectors and suggest novel strategies for B. tabaci pest management. [ABSTRACT FROM AUTHOR]

Hepatocyte nuclear factor 4 (HNF4) is essential for glucose homeostasis and lipid metabolism in insects. However, little is known about the role of HNF4 in whiteflies. In the present study, we identified a hepatocyte nuclear factor protein from Bemsia tabaci (Diptera: Drosophilidae) and named it BtabHNF4. The full-length of BtabHNF4 was 3,006 bp, encoding a sequence of 434 amino acids that contains a conserved zinc-finger DNA-binding domain (DBD) and a well-conserved ligand-binding domain (LBD). The temporal and spatial expression showed that BtabHNF4 was highly expressed in the female adult stage and abdominal tissues of B. tabaci. A leaf-mediated RNA interference method was used to explore the function of BtabHNF4 in whiteflies. Our results showed that the knockdown of BtabHNF4 influences the desiccation tolerance, egg production, and egg hatching rate of whiteflies. Additionally, BtabHNF4 silencing significantly inhibited the expression level of vitellogenin. These results expand the function of HNF4 and pave the way for understanding the molecular mechanisms of HNF4 in regulating multiple physiological processes. [ABSTRACT FROM AUTHOR]

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most damaging, polyphagous insect pests of agricultural cropping systems around the world. Insecticide control is one of the main tactics used to mitigate damage and crop injury caused by the species. Similarly, plant chemical defenses are primary natural mechanisms that reduce attacks from whiteflies. Like all Sternorrhyncha insects, whiteflies have piercing/sucking mouthparts and feed on phloem sap from vascular plants through a stylet. Therefore, if this insect can overcome the physical barriers of the plant and pierce the vascular bundle, the main remaining barriers to nutrition uptake and utilization are phytochemicals that might exhibit some degree of toxicity toward the insect. Bemisia tabaci has been reported to feed on over 1,000 plant species representing an enormous range of phytochemicals to which whiteflies are potentially exposed. Recently, whiteflies were shown to have acquired a gene from plants to detoxify the plant's phenolic glycosides that are usually toxic. Additionally, host plants have been shown to alter the response of a single whitefly population to insecticides. Herein, we review possible interactions between the highly polyphagous B. tabaci, the potential phytochemicals associated with its extensive plant host range, and the main chemical insecticides used to control this pest. This review aims to provide a conceptual framework for studying possible biological interactions between the insect, host plant, and insecticidal toxins used to control this pest at the mechanistic and population selection levels. [ABSTRACT FROM AUTHOR]

The extent to which horizontal gene transfer (HGT) has shaped eukaryote evolution remains an open question. Two recent studies reported four plant-like genes acquired through two HGT events by the whitefly Bemisia tabaci , a major agricultural pest (Lapadula WJ, Mascotti ML, Juri Ayub M. 2020. Whitefly genomes contain ribotoxin coding genes acquired from plants. Sci Rep. 10(1):15503; Xia J, et al. 2021. Whitefly hijacks a plant detoxification gene that neutralizes plant toxins. Cell 184(7):1693–1705 e1617.). Here, we uncovered a total of 49 plant-like genes deriving from at least 24 independent HGT events in the genome of the Middle East Asia Minor 1 (MEAM1) whitefly. Orthologs of these genes are present in three cryptic B. tabaci species, they are phylogenetically nested within plant sequences, they are expressed and have evolved under purifying selection. The predicted functions of these genes suggest that most of them are involved in plant–insect interactions. Thus, substantial plant-to-insect HGT may have facilitated the evolution of B. tabaci toward adaptation to a large host spectrum. Our study shows that eukaryote-to-eukaryote HGT may be relatively common in some lineages and it provides new candidate genes that may be targeted to improve current control strategies against whiteflies. [ABSTRACT FROM AUTHOR]

The Bemisia tabaci species complex is a group of tropical–subtropical hemipterans, some species of which have achieved global distribution over the past 150 years. Several species are regarded currently as among the world's most pernicious agricultural pests, causing a variety of damage types via direct feeding and plant-disease transmission. Long considered a single variable species, genetic, molecular and reproductive compatibility analyses have revealed that this "species" is actually a complex of between 24 and 48 morphologically cryptic species. However, determinations of which populations represent distinct species have been hampered by a failure to integrate genetic/molecular and morphological species–diagnoses. This, in turn, has limited the success of outbreak-control and eradication programs. Previous morphological investigations, based on traditional and geometric morphometric procedures, have had limited success in identifying genetic/molecular species from patterns of morphological variation in puparia. As an alternative, our investigation focused on exploring the use of a deep-learning convolution neural network (CNN) trained on puparial images and based on an embedded, group-contrast training protocol as a means of searching for consistent differences in puparial morphology. Fifteen molecular species were selected for analysis, all of which had been identified via DNA barcoding and confirmed using more extensive molecular characterizations and crossing experiments. Results demonstrate that all 15 species can be discriminated successfully based on differences in puparium morphology alone. This level of discrimination was achieved for laboratory populations reared on both hairy-leaved and glabrous-leaved host plants. Moreover, cross-tabulation tests confirmed the generality and stability of the CNN discriminant system trained on both ecophenotypic variants. The ability to identify B. tabaci species quickly and accurately from puparial images has the potential to address many long-standing problems in B. tabaci taxonomy and systematics as well as playing a vital role in ongoing pest-management efforts. [Aleyrodidae; entomology; Hemiptera; machine learning; morphometrics; pest control; systematics; taxonomy; whiteflies.] [ABSTRACT FROM AUTHOR]

The whitefly, Bemisia tabaci (Gennadius), is a key pest of many economically important crops grown in the field and in greenhouses throughout the world. Because entomopathogenic fungi (EPF) are potential biological control agents for B. tabaci , however, minimal research has been conducted on using fungal strains to control B. tabaci. In this study, four EPF strains were isolated and identified as Lecanicillium attenuatum (Zare & Gams) JL-003, Beauveria bassiana Balsamo (Vuillemin) JL-005, Lecanicillium longisporum (Petch) JL-006, and Akanthomyces lecanii (Zimmerman) JL-007, based on rDNA-ITS sequence analysis. In comparing the virulence of the four fungi against the different life stages (i.e. eggs, 1st-, 2nd-, 3rd-, 4th-instar nymphs, and adults) of B. tabaci the mortality of B. tabaci decreased and LT50 values increased as the conidia concentration decreased in a series of conidia concentrations (1 × 105, 106, 107, and 108 conidia/mL). The fungal strains L. attenuatum JL-003 (LC50: 1.31 × 106) and B. bassiana JL-005 (LC50: 0.92 × 106) were found to be more effective than L. longisporum JL-006 (LC50: 4.97 × 107) and A. lecanii JL-007 (LC50: 6.46 × 106). Fourth-instar nymphs, eggs, and adult stages of B. tabaci were less susceptible to all fungal strains compared to 1st-, 2nd-, and 3rd-instar nymphs. The virulence of L. attenuatum, which was tested for the first time on B. tabaci , was found to be more toxic to early-stage nymphs. Our data will be useful in biological control programs that are considering using EPF against B. tabaci. [ABSTRACT FROM AUTHOR]

Bemisia tabaci MEAM1 (Hemiptera: Aleyrodidae) is a key insect pest in soybean fields in Brazil but data are lacking on the relationship between pest abundance and crop yield and quality. Controlled infestation studies were conducted on caged soybean plants in the field over a two year period at two sites in Brazil. Differences in temperature in the two years affected population growth of B. tabaci , reaching 413 nymphs per leaflet in the first year, and 179 the second year even when the average temperature was 3ºC higher. Higher temperatures promoted a shorter lifecycle and nearly one more generation. Yield was affected with losses up to 500 kg/ha in 2017/2018 and 1,147 kg/ha in 2018/2019. A decrease in the weight of a thousand grains of 18 and 33 g was observed in the first and second year, respectively. No significant differences were observed in grain germination, but estimated losses in protein content were up to 440 kg/ha at the highest infestation level. Pest density and yield data were used to estimate economic injury levels (EILs). EILs ranged from 2.5 to 25.67 nymphs per leaflet and 0.17–1.79 adults per leaflet over a range of control costs, soybean production values, and control efficacies. These results should provide data useful toward development of pest management decision making tools. [ABSTRACT FROM AUTHOR]

Insects often coevolved with their mutualistic partners such as gut endosymbionts, which play a key in the physiology of host. Studies on such interactions between Bemisia tabaci and its primary and secondary endosymbionts have gained importance due to their indispensable roles in the biology of this insect. Present study reports the predominance of two secondary endosymbionts, Arsenophonus and Cardinium in the Asia II-1 genetic group of whitefly and elucidates their role in the transmission of its vectored Cotton leaf curl virus. Selective elimination of endosymbionts was optimized using serial concentration of ampicillin, chloramphenicol, kanamycin, tetracycline, and rifampicin administered to viruliferous whiteflies through sucrose diet. Primary endosymbiont, Portiera was unresponsive to all the antibiotics, however, rifampicin and tetracycline at 90 μg/ml selectively eliminated Arsenophonus from the whitefly. Elimination of Arsenophonus resulted in significant decrease in virus titer from viruliferous whitefly, further the CLCuV transmission efficiency of these whiteflies was significantly reduced compared to the control flies. Secondary endosymbiont, Cardinium could not be eliminated completely even with higher concentrations of antibiotics. Based on the findings, Arsenophonus plays a key role in the retention and transmission of CLCuV in the Asia II-1 genetic group of B. tabaci, while the role of Cardinium could not be established due to its unresponsiveness to antibiotics. [ABSTRACT FROM AUTHOR]

The greenhouse whitefly, Trialeurode vaporariorum, is among the key pests of tomato (Solanum lycopersicum) in sub-Saharan Africa with Tuta absoluta, spider mite, thrips, and fruitworms. To understand the interaction between the pest and the plant's herbivory-induced plant volatile (HIPVs), we investigated the repellency of four tomato cultivars (Kilele F1, Assila F1, Red Beauty F1, and Nemonneta F1) upon infestation by Trialeurode vaporariorum. We analyzed the behavioral response of T. vaporariorum to infested and uninfested tomato plants of these cultivars using olfactory bioassays followed by gas chromatography–mass spectrometry (GC–MS) analyses of emitted volatiles. Trialeurode vaporariorum was attracted to uninfested plants of all four tomato cultivars. However, two cultivars Kilele F1 and Red Beauty F1 were no longer attractive to the whitefly when they were already infested by the pest. GC–MS analyses identified 25 compounds, 18 monoterpenes, 3 sesquiterpenes, 2 xylenes, 1 aldehyde, and 1 carboxylic compound in the 4 uninfested and infested cultivars. Based on the insects' behavioral response, 1,8-cineole, p-cymene, and limonene did not attract T. vaporariorum at varying concentrations when combined with Red Beauty F1, the most attractive tomato cultivar. This repellence behavioral response can be used as a basis for improvement of other vegetable crops for the management of arthropod pests as for odor masking technique. Graphical Abstract [ABSTRACT FROM AUTHOR]

Whiteflies (Bemisia tabaci) represent an insect pest in horticulture. It serves as a vector for transmitting phytopathogens that inhibit the correct development of plants, affecting crop performance. In this research, whitefly population model was proposed to provide a tool that predicts the pest spread within a crop under greenhouse conditions. The analysis, calibration, and validation of the models, based on logistic functions, were implemented for the three stages (egg, nymph, and adult) of the life cycle of this organism. Temperature (°C), relative humidity (%), initial population (number/cm2), and Growing Degree-Day (GDD) were considered as input variables to describe each development stage. The statistical analysis for the model validation included the coefficient of determination (R 2), the percentage standard error of prediction (%SEP), the average relative variance (AVR), and the efficiency coefficient (E). The first period for calibration consisted of 43 d (204.3 GDD), and the second period for validation consisted of 36 d (171.1 GDD). The model efficiently predicts the population growth for the egg, nymph, and adult stages since the values of R 2 were 0.9856, 0.9918, and 0.9436, and the values of %SEP were 12.4, 11.9, and 75.1% for the egg, nymph, and adult stages, respectively. Moreover, the validation model obtained an R 2 of 0.9287 for the egg stage, 0.9645 for the nymph stage, and 0.9884 for the adult stage. Meanwhile, the values of %SEP were 10.38, 16.89, and 32.59% for the egg, nymph, and adult stages, respectively. In both cases, the values suggest an adequate fit for the model. [ABSTRACT FROM AUTHOR]

The whitefly, Bemisia tabaci is a hemipteran pest of vegetable crops vectoring a broad category of viruses. Currently, this insect pest showed a high adaptability and resistance to almost all the chemical compounds commonly used for its control. In many cases, transposable elements (TEs) contributed to the evolution of host genomic plasticity. This study focuses on the annotation of Mariner-like elements (MLEs) and their derived Miniature Inverted repeat Transposable Elements (MITEs) in the genome of B. tabaci. Two full-length MLEs belonging to mauritiana and irritans subfamilies were detected and named Btmar1.1 and Btmar2.1, respectively. Additionally, 548 defective MLE sequences clustering mainly into 19 different Mariner lineages of mauritiana and irritans subfamilies were identified. Each subfamily showed a significant variation in MLE copy number and size. Furthermore, 71 MITEs were identified as MLEs derivatives that could be mobilized via the potentially active transposases encoded by Btmar 1.1 and Btmar2.1. The vast majority of sequences detected in the whitefly genome present unusual terminal inverted repeats (TIRs) of up to 400 bp in length. However, some exceptions are sequences without TIRs. This feature of the MLEs and their derived MITEs in B. tabaci genome that distinguishes them from all the other MLEs so far described in insects, which have TIRs size ranging from 20 to 40bp. Overall, our study provides an overview of MLEs, especially those with large TIRs, and their related MITEs, as well as diversity of their families, which will provide a better understanding of the evolution and adaptation of the whitefly genome. [ABSTRACT FROM AUTHOR]

We examined the feasibility of externally marking insects with the liquid fluorescent forensic theft deterrent, SmartWater (SmartWater CSI, LLC.). We sprayed captive Lygus hesperus (Knight) (Hemiptera: Miridae), Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), and Hippodamia convergens Guérin-Méneville (Coleoptera: Coccinellidae) with SmartWater fluorophore, and then qualitatively examined them for fluorescence by visual inspection under ultraviolet (UV) light and quantitatively measured them with a multiwavelength microplate fluorometer. The results indicate that this product has enormous potential as a taggant for L. hesperus and B. tabaci. However, the marking efficiency for H. convergens was only adequate. The advantages and limitations of using SmartWater as a biological marker for arthropod mark-release-recapture research are discussed. [ABSTRACT FROM AUTHOR]

A new strain of the entomopathogenic fungus, identified as Cordyceps javanica (Frieder. & Bally) Kepler, B. Shrestha & Spatafora (Hypocreales: Cordycipitaceae) wf GA17, was found naturally infecting the sweetpotato whitefly, Bemisia tabaci (Gennadius) MEAM1 in southern Georgia, US, in September 2017. The fungus was tested for pathogenicity and virulence in comparison with commercially available entomopathogenic fungal strains against several insect species in the laboratory. In specific, it was compared with Cordyceps fumosorosea (Wize) Kepler, B. Shrestha & Spatafora (Hypocreales: Cordycipitaceae) Apopka 97, Beauveria bassiana (Bals.-Criv.) Vuill. (Hypocreales: Cordycipitaceae) strain GHA, and Metarhizium brunneum Petch (Hypocreales: Clavicipitaceae) strain F52 for virulence against B. tabaci (4th instars) and cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae) (4th instars with or without wingbuds), on leaf-discs, and against last instars of pecan weevil Curculio caryae (Horn) (Coleoptera: Curculionidae) and citrus root weevil Diaprepes abbreviatus (L.) (Coleoptera: Curculionidae) in soil cups. Against B. tabaci , C. javanica exhibited higher mortality and mycosis development at 5 d post inoculation than other fungi. In assays against A. gossypii with and without wingbuds, C. javanica and C. fumosorosea had the highest mortality and mycosis levels and B. bassiana had the lowest; nymphs with wingbuds were more susceptible to some fungal infection than those without. Against C. caryae , B. bassiana was more effective than other fungi. For D. abbreviatus , B. bassiana also caused the highest mortality while M. brunneum had the lowest, with Cordyceps spp. being intermediate. Overall, the findings suggest high potential of the new strain, C. javanica wf GA17, for managing whiteflies and aphids, while it was not as effective as B. bassiana against the curculionids. [ABSTRACT FROM AUTHOR]

Metabolic conversions allow organisms to produce essential metabolites from the available nutrients in an environment, frequently requiring metabolic exchanges among co-inhabiting organisms. Here, we applied genomic-based simulations for exploring tri-trophic interactions among the sap-feeding insect whitefly (Bemisia tabaci), its host-plants, and symbiotic bacteria. The simplicity of this ecosystem allows capturing the interacting organisms (based on genomic data) and the environmental content (based on metabolomics data). Simulations explored the metabolic capacities of insect-symbiont combinations under environments representing natural phloem. Predictions were correlated with experimental data on the dynamics of symbionts under different diets. Simulation outcomes depict a puzzle of three-layer origins (plant-insect-symbionts) for the source of essential metabolites across habitats and stratify interactions enabling the whitefly to feed on diverse hosts. In parallel to simulations, natural and artificial feeding experiments provide supporting evidence for an environment-based effect on symbiont dynamics. Based on simulations, a decrease in the relative abundance of a symbiont can be associated with a loss of fitness advantage due to an environmental excess in amino-acids whose production in a deprived environment used to depend on the symbiont. The study demonstrates that genomic-based predictions can bridge environment and community dynamics and guide the design of symbiont manipulation strategies. [ABSTRACT FROM AUTHOR]

Community science, which engages students and the public in data collection and scientific inquiry, is often integrated into conservation and long-term monitoring efforts. However, it has the potential to also introduce the public to, and be useful for, sensory ecology and other fields of study. Here we describe a community science project that exposes participants to animal behavior and sensory ecology using the rich butterfly community of Northwest Arkansas, United States. Butterflies use visual signals to communicate and to attract mates. Brighter colors can produce stronger signals for mate attraction but can also unintentionally attract negative attention from predators. Environmental conditions such as weather can affect visual signaling as well, by influencing the wavelengths of light available and subsequent signal detection. However, we do not know whether the signals butterflies present correlate broadly with how they behave. In this study, we collaborated with hundreds of students and community members at the University of Arkansas (UARK) and the Botanical Gardens of the Ozarks (BGO) for over 3.5 years to examine relationships among wing pattern, weather, time of day, behavior, and flower choice. We found that both weather and wing color influenced general butterfly behavior. Butterflies were seen feeding more on cloudy days than on sunny or partly cloudy days. Brown butterflies fed or sat more often, while white butterflies flew more often relative to other butterfly colors. We also found that there was an interaction between the effects of weather and wing color on butterfly behavior. Furthermore, butterfly color predicted the choice of flower colors that butterflies visited, though this effect was influenced by the observer group (UARK student or BGO participant). These results suggest that flower choice may be associated with butterfly wing pattern, and that different environmental conditions may influence butterfly behavior in wing-pattern–specific ways. They also illustrate one way that public involvement in behavioral studies can facilitate the identification of coarse-scale, community-wide behavioral patterns, and lay the groundwork for future studies of sensory niches. [ABSTRACT FROM AUTHOR]

Plant viruses can change the phenotypes and defense pathways of the host plants and the performance of their vectors to facilitate their transmission. Cucurbit chlorotic yellows virus (CCYV) (Crinivirus), a newly reported virus occurring on cucurbit plants and many other plant species, is transmitted specifically by Bemisia tabaci MEAM1 (B biotype) and MED (Q biotype) cryptic species in a semipersistent manner. This study evaluated the impacts of CCYV on B. tabaci to better understand the plant-virus-vector interactions. By using CCYV- B. tabaci MED - cucumber as the model, we investigated whether or how a semipersistent plant virus impacts the biology of its whitefly vector. CCYV mRNAs were detectable in nymphs from first to fourth instars and adults of B. tabaci with different titers. Nymph instar durations and adult longevity of female whiteflies greatly extended on CCYV-infected plants, but nymph instar durations and adult longevity of male whiteflies were not significantly influenced. In addition, the body length and oviposition increased in adults feeding on CCYV-infected plants, but the hatching rates of eggs and survival rates of different stages were not affected. Most interestingly, the sex ratio (male:female) significantly reduced to 0.5:1 in whitefly populations on CCYV-infected plants, while the ratio remained about 1:1 on healthy plants. These results indicated that CCYV can significantly impact the biological characteristics of its vector B. tabaci. It is speculated that CCYV and B. tabaci have established a typical mutualist relationship mediated by host plants. [ABSTRACT FROM AUTHOR]

Many damaging agricultural pests can, in addition to their direct feeding damage, acquire and transmit plant pathogens. Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) is considered a 'supervector' of disease-causing plant pathogens and viruses. One of the most damaging of these is Tomato yellow leaf curl virus (TYLCV), a circulatively transmitted begomovirus than can extensively damage field and greenhouse crops. Because sustained feeding periods are necessary to acquire and transmit circulatively transmitted viruses, pesticides that, in addition to their direct lethality, suppress feeding in surviving individuals may be particularly effective in decreasing viral transmission. We assessed the impact of sulfoxaflor, a sulfoximine insecticide, on the settling preference, feeding, and viral transmission of TYLCV-carrying B. tabaci on tomato. We found that viruliferous B. tabaci avoided both settling and feeding on sulfoxaflor-treated plants, and that sulfoxaflor virtually eliminated the transmission of TYLCV by B. tabaci. The antifeedant properties of sulfoxaflor have previously been reported in other pest systems; our results document similar effects on viruliferous B. tabaci and demonstrate that this pesticide can reduce TYLCV transmission by surviving individuals. [ABSTRACT FROM AUTHOR]

Pesticides primarily affect target organisms via direct toxicity, but may also alter the feeding behaviors of surviving individuals in ways that alter their effect on host plants. The latter impact is especially important when pests can transmit plant pathogens. The Mediterranean (MED) population of the sweetpotato whitefly Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) transmits Tomato yellow leaf curl virus (TYLCV), a pathogen that can be economically devastating in field and greenhouse cropping systems. We first assessed the impact of sublethal (LC15) and label concentrations of flupyradifurone, a butenolide-derived insecticide, on the feeding behavior of TYLCV-infected MED on tomato. We next measured the effect of flupyradifurone on plant TYLCV load, vector transmission efficiency, and MED survival. Both the LC15 and label flupyradifurone concentrations dramatically altered MED feeding and caused the near cessation of both salivation and phloem ingestion (necessary for viral transmission and acquisition, respectively). Both concentrations also significantly reduced plant TYLCV load, and the label rate of flupyradifurone sharply decreased TYLCV transmission while killing >99% of MED. As the first report of pesticide-induced changes in the feeding behavior of viruliferous Bemisia , our findings highlight the potential importance of chemically driven feeding cessation in the control of TYLCV and other Bemisia -transmitted plant pathogens. [ABSTRACT FROM AUTHOR]

Whether increased natural enemy density or adding a second natural enemy species will provide superior pest suppression in greenhouse augmentative biological control is unknown for many commercially available natural enemy species. In this study, we use sweetpotato whiteflies, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), on poinsettias, Euphorbia pulcherrima Willd. ex Klotzsch (Malpighiales: Euphorbiaceae), to determine whether adding Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) to Eretmocerus eremicus Rose and Zolnerowich (Hymenoptera: Aphelinidae) is better for B. tabaci suppression compared with either natural enemy alone, both with and without challenges with whitefly immigration or delayed natural enemy releases. The number of whiteflies on caged poinsettias treated with different natural enemy release rates (single or double rate), natural enemy species (one or two species), natural enemy delayed release (weeks 4 and 8), and whitefly immigration treatments (introduced at week 4 or week 8) was censused biweekly for 16 wk. Both species used in combination provided similar or better suppression of whiteflies compared with either natural enemy alone. Both species combined also provided superior suppression of whiteflies when challenged with whitefly immigration or delays in natural enemy releases compared with E. eremicus alone. Whitefly immigration or delays in E. eremicus releases did not increase whitefly populations, suggesting that suppression of whiteflies by E. eremicus alone is relatively robust. This study found no evidence for negative interactions between E. eremicus and A. swirskii for suppressing B. tabaci. [ABSTRACT FROM AUTHOR]

Facultative endosymbionts can affect the growth, physiology, and behavior of their arthropod hosts. There are several endosymbionts in the invasive whitefly Bemisia tabaci Mediterranean (MED, Q biotype) that influence host fitness by altering stylet probing behavior. We investigated the probing behavior of B. tabaci MED infected with the facultative endosymbiont Candidatus Cardinium hertigii (Cardinium (Sphingobacteriales: Flexibacteraceae)). We generated genetically similar Cardinium -infected (C*+) and uninfected (C-) clonal sublines and analyzed the probing behavior of newly emerged adult on cotton (Malvales: Malvaceae), Gossypium hirsutum L. using electropenetrography (EPG). The C- subline demonstrated a longer duration of E2 (2.81-fold) and more events of E2 (2.22-fold) than the C*+ subline, indicating a greater level of sustained ingestion of plant phloem. These findings provide insight into the fitness costs (fitness of a particular genotype is lower than the average fitness of the population) of the Cardinium -infected B. tabaci. [ABSTRACT FROM AUTHOR]

The whitefly Bemisia tabaci is a destructive agricultural pest that frequently harbors various species of secondary symbionts including Rickettsia. Previous studies have revealed that the infection of Rickettsia can improve whitefly performance on food plants; however, to date, no evidence has shown, if, and how, Rickettsia manipulates the plant-insect interactions. In the current study, the effects of Rickettsia persistence on the induced plant defenses and the consequent performance of whitefly B. tabaci were investigated. Results revealed that Rickettsia can be transmitted into plants via whitefly feeding and remain alive within the cotton plants for at least 2 weeks. The different expression genes of cotton plants were mostly concentrated in the phytohormone signaling pathways, the marker genes of jasmonic-acid signaling pathway (AOC, AOS, LOX, MYC2) were significantly downregulated, while the marker genes of the salicylic-acid signaling pathway (WRKY70, PR-1) were upregulated. Biological experiments revealed that the fecundity of Rickettsia negative B. tabaci significantly increased when they fed on Rickettsia -persistent cotton plants. Taken together, we provide experimental evidence that the persistence of Rickettsia and its induced defense responses in cotton plants can increase the fitness of whitefly and, by this, Rickettsia may increase its infection and spread within its whitefly host. [ABSTRACT FROM AUTHOR]

Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R 0) 100% higher and intrinsic rate of population increase (r m ) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties. [ABSTRACT FROM AUTHOR]

In nature, a plant can be infected by multiple viruses simultaneously. However, the effects of coinfection on plant–vector interactions are less well studied. Two begomoviruses of the family Geminiviridae, Tomato yellow leaf curl virus (TYLCV) and Tomato yellow leaf curl China virus (TYLCCNV), occur sympatrically in China. Each of them is reported to increase the performance of whitefly vector via manipulation of plant traits. In this study, we examined the effects of coinfection by the two viruses TYLCV and TYLCCNV on plant–whitefly interactions, compared to that infected by a single virus. We found that plants infected by two viruses showed aggravated symptoms but the performance and preference of whiteflies were not altered significantly compared to singly-infected plants. Coinfection suppressed the transcription of genes involved in jasmonic acid (JA) signaling pathway in plants, but showed no significant difference to single-virus infected plants. These findings suggest that although TYLCV and TYLCCNV may synergistically induce plant symptoms, they did not manipulate synergistically plant-mediated responses to the insect vector. [ABSTRACT FROM AUTHOR]

Bemisia tabaci (Gennadius) cryptic complex has invaded Xinjiang, China, since 1998. The distribution of Mediterranean (MED) and Middle East-Asia Minor 1 (MEAM1) B. tabaci substrains has been gradually identified due to the development of molecular technology. In this study, the distribution of MED and MEAM1 in Xinjiang was determined by cleaved amplified polymorphic sequence (CAPs). Results showed that MED dominated in northern Xinjiang (84%), whereas MEAM1 was dominant in southern Xinjiang (72%). Five pairs of simple sequence repeat (SSR) primers were used to analyze the genetic diversity of B. tabaci among 36 geographic populations. The genetic diversity of MED and MEAM1was low and varied little among populations in Xinjiang (0.09 ± 0.14 and 0.09 ± 0.13, respectively). Based on ∆ K statistic, 13 populations of MEAM1 could be classified into two subgroups at K = 2, whereas the 23 populations of MED could be classified into four subgroups at K = 4. However, Mantel t -test demonstrated no correlation between geographical and genetic distances among B. tabaci complex (R = 0.42, P = 1.00). Neighbor-joining and principal coordinate analysis showed that geographical isolation and interspecific differences were the main causes of the genetic variation. Gene flow predicted that MEAM1 was most likely introduced from Urumqi to the southern Xinjiang. Meanwhile, a large proportion of MED in Kashi region came from Changji and Yining. To block ongoing dispersal, strict detection and flower quarantine regulations need to be enforced. [ABSTRACT FROM AUTHOR]

The effects of rearing temperature and host stage parasitized on the development of three parasitoid species; Encarsia noyesi Hayat (Hymenoptera: Aphelinidae), Idioporus affinis LaSalle & Polaszek (Hymenoptera: Pteromalidae), and Entedononecremnus krauteri Zolnerowich & Rose (Hymenoptera: Eulophidae) were investigated. These parasitoids are part of the biological control program for the giant whitefly Aleurodicus dugesii Cockerell (Hemiptera: Aleyrodidae) in the United States. Temperature and host-dependent development was assessed for each species using the nonlinear Brière-1 model and simple linear regression to obtain critical thermal parameters. All three parasitoids successfully developed at constant temperatures ranging from 15°C to 30°C, which was narrower to their predicted thermal limits due to thermal constraints of A. dugesii. There were significant effects of both temperature and A. dugesii nymphal stage parasitized on immature parasitoid development times. All three parasitoid species' development time decreased as nymphal stage age increased. Thermal tolerance limits and development times varied by parasitoid species. The results of these findings in the context of biological control potential are discussed. [ABSTRACT FROM AUTHOR]

The house fly is a ubiquitous pest commonly associated with animal facilities and urban waste. When present in large numbers, house flies can negatively impact humans and animals through nuisance and the transmission of pathogens. Since the development of fly traps and sticky papers to capture flies in the late 1800s, these and other methods have been used as a means to monitor change in house fly density or fly activity over time. Methods include substrate sampling to record density of immature flies, visual observations of adult fly activity, instantaneous counts of landing or resting flies, accumulation of adult flies on/in traps, or accumulation of fly fecal and regurgitation spots deposited by flies onto white cards. These methods do not estimate true house fly density, but rather provide an index of house fly activity that is related to both fly density and the frequency of individual fly behavior (e.g. frequency of flight, landing events) and which is likely more predictive of negative impacts such as nuisance and pathogen transmission. Routine monitoring of house fly activity is a critical component of a house fly management program. Fly activity should be held to a level below a predetermined activity threshold ('action threshold') above which negative impacts are anticipated to occur. This article is a review of methods utilized for monitoring house fly (Diptera: Muscidae) activity. [ABSTRACT FROM AUTHOR]

In Costa Rica, tomato (Solanum lycopersicum Linnaeus) Linnaeus (Solanales: Solanaceae) is one of the crops most severely affected by the whiteflies (Hemiptera: Aleyrodidae) Trialeurodes vaporariorum (Westwood) and the Bemisia tabaci (Gennadius) species complex. The objective of this study was to monitor the spatial distribution and diversity of these species and to detect the presence of secondary bacterial endosymbionts in individuals collected in areas of intensive tomato production. In total, 628 whitefly individuals were identified to the species level using restriction analysis (PCR-RFLP) of a fragment of the mitochondrial cytochrome C oxidase I gene (mtCOI). Trialeurodes vaporariorum was the predominant species, followed by B. tabaci Mediterranean (MED). Bemisia tabaci New World (NW) and B. tabaci Middle East-Asia Minor 1 (MEAM1) were present in lower numbers. The mtCOI fragment was sequenced for 89 individuals and a single haplotype was found for each whitefly species. Using molecular markers, the 628 individuals were analyzed for the presence of four endosymbionts. Arsenophonus Gherna et al. (Enterobacterales: Morganellaceae) was most frequently associated with T. vaporariorum , whereas Wolbachia Hertig (Rickettsiales: Anaplasmataceae) and Rickettsia da Rocha-Lima (Rickettsiales: Rickettsiaceae) were associated with B. tabaci MED. This study confirmed that B. tabaci NW has not been completely displaced by the invasive species B. tabaci MED and B. tabaci MEAM1 present in the country. An association was found between whitefly species present in tomato and certain secondary endosymbionts, elevation was the most likely environmental factor to affect their frequency. [ABSTRACT FROM AUTHOR]

Background Many plant viruses are vector-borne and depend on arthropods for transmission between host plants. Begomoviruses, the largest, most damaging and emerging group of plant viruses, infect hundreds of plant species, and new virus species of the group are discovered each year. Begomoviruses are transmitted by members of the whitefly Bemisia tabaci species complex in a persistent-circulative manner. Tomato yellow leaf curl virus (TYLCV) is one of the most devastating begomoviruses worldwide and causes major losses in tomato crops, as well as in many agriculturally important plant species. Different B. tabaci populations vary in their virus transmission abilities; however, the causes for these variations are attributed among others to genetic differences among vector populations, as well as to differences in the bacterial symbionts housed within B. tabaci. Results Here, we performed discovery proteomic analyses in 9 whitefly populations from both Middle East Asia Minor I (MEAM1, formerly known as B biotype) and Mediterranean (MED, formerly known as Q biotype) species. We analysed our proteomic results on the basis of the different TYLCV transmission abilities of the various populations included in the study. The results provide the first comprehensive list of candidate insect and bacterial symbiont (mainly Rickettsia) proteins associated with virus transmission. Conclusions Our data demonstrate that the proteomic signatures of better vector populations differ considerably when compared with less efficient vector populations in the 2 whitefly species tested in this study. While MEAM1 efficient vector populations have a more lenient immune system, the Q efficient vector populations have higher abundance of proteins possibly implicated in virus passage through cells. Both species show a strong link of the facultative symbiont Rickettsia to virus transmission. [ABSTRACT FROM AUTHOR]

Whiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are a superfamily of small phloem-feeding insects. They rely on their primary endosymbionts " Candidatus Portiera aleyrodidarum" to produce essential amino acids not present in their diet. Portiera has been codiverging with whiteflies since their origin and therefore reflects its host's evolutionary history. Like in most primary endosymbionts, the genome of Portiera stays stable across the Aleyrodidae superfamily after millions of years of codivergence. However, Portiera of the whitefly Bemisia tabaci has lost the ancestral genome order, reflecting a rare event in the endosymbiont evolution: the appearance of genome instability. To gain a better understanding of Portiera genome evolution, identify the time point in which genome instability appeared and contribute to the reconstruction of whitefly phylogeny, we developed a new phylogenetic framework. It targeted five Portiera genes and determined the presence of the DNA polymerase proofreading subunit (dnaQ) gene, previously associated with genome instability, and two alternative gene rearrangements. Our results indicated that Portiera gene sequences provide a robust tool for studying intergenera phylogenetic relationships in whiteflies. Using these new framework, we found that whitefly species from the Singhiella , Aleurolobus , and Bemisia genera form a monophyletic tribe, the Aleurolobini, and that their Portiera exhibit genome instability. This instability likely arose once in the common ancestor of the Aleurolobini tribe (at least 70 Ma), drawing a link between the appearance of genome instability in Portiera and the switch from multibacteriocyte to a single-bacteriocyte mode of inheritance in this tribe. [ABSTRACT FROM AUTHOR]

The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera; Aleyrodidae), and greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), are highly problematic plant pests and virus vectors with worldwide distributions. Identification of whitefly species is typically accomplished by observation of distinct morphological characters; however, because of morphological inconsistency and indistinguishability, the discrimination of B. tabaci species variants is dependent on molecular techniques based on genetic differences. New assays were designed for the detection of B. tabaci A, B, and Q mitotype groups, and T. vaporariorum. Specific primer sets were designed for amplification of the mitochondrial cytochrome c oxidase I gene of the four targets to perform in end-point PCR, real-time PCR coupled to high-resolution melting analysis (HRM), and the isothermal helicase-dependent amplification (HDA). Primer specificities were validated using end-point PCR, then tested in HRM and HDA. Bemisia tabaci A, B, and Q mitotypes, and T. vaporariorum -targeted primer sets discriminately amplified specimens of different populations within their target whitefly group. These tests provide three novel discrimination assays for the high-consequence, exotic B. tabaci B and Q groups, along with the native B. tabaci A group and T. vaporariorum. [ABSTRACT FROM AUTHOR]

The sweetpotato whitefly, Bemisia tabaci MEAM1 Gennadius, is a global pest of tomato, transmitting Tomato yellow leaf curl virus (TYLCV). Management of B. tabaci is challenging in part because of its ability to develop resistance to insecticides. Biopesticides include materials that control B. tabaci via mechanisms that do not select for resistance. Field experiments were conducted in the spring and fall of 2016 and 2017 at the University of Florida's Gulf Coast Research and Education Center in west central Florida to compare biopesticides to conventional insecticides for management of B. tabaci and TYLCV. Insecticide rotations were designed in part around the concept that conventional insecticide programs should group modes of action according to 5-wk treatment intervals, corresponding to an estimated 5-wk generation time for the pest. In 2016, when tomato was treated during the first 5-wk treatment interval with either biopesticides or neonicotinoid insecticides, insecticidal soap contributed to a reduction in whitefly egg numbers and percentage TYLCV that was comparable to results achieved with dinotefuran. In contrast, egg numbers and virus incidence in plants treated with kaolin clay tended to be numerically higher than the untreated control. In spring 2017, comparisons of biopesticides and conventional ovicides/nymphicides during the second 5-wk treatment interval showed that biopesticides can provide comparable reduction in nymph numbers to conventional insecticides. While data from these trials confirm that biopesticides can reduce numbers of whitefly eggs and nymphs, they indicate that season-long programs of the biopesticides evaluated may not reduce transmission of TYLCV below economically acceptable levels. [ABSTRACT FROM AUTHOR]

The whitefly, Bemisia tabaci Gennadius, is a major phloem-feeding pest of agricultural crops that is also an important vector of many plant diseases. The B. tabaci Mediterranean ('MED') biotype is a particularly effective vector of Tomato yellow leaf curl virus (TYLCV), a devastating plant pathogen. Although insecticides play an important role in the control of MED and TYLCV, little is known about how TYLCV infection affects MED susceptibility to insecticides. We conducted research addressing how MED susceptibility to flupyradifurone, the first commercially available systemic control agent derived from the butenolide class of insecticides, was affected by TYLCV infection. We first conducted bioassays determining the LC15 and LC50 for control and viruliferous MED feeding on either water- or insecticide-treated plants. We next measured several demographic parameters of control and viruliferous MED exposed to either insecticide- or water-treated plants. TYLCV infection increased MED tolerance of flupyradifurone: the LC15 and LC50 of viruliferous MED were double that of uninfected MED. Viral infection also altered MED demographic responses to flupyradifurone, but in an inconsistent manner. Although the ability of TYLCV and other persistently transmitted viruses to benefit Bemisia via manipulation of host plant defense is well known, this appears to be the first example of virally mediated changes in vector susceptibility to an insecticide. [ABSTRACT FROM AUTHOR]

The Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex comprises important pests and virus vectors in agricultural crops worldwide. In China, B. tabaci has spread to more than 20 provinces and caused severe losses of vegetables, fruits, and ornamental plants. However, B. tabaci has developed resistance to many insecticidal classes in Shandong Province, eastern China. In this study, we investigated the cryptic species, insecticide resistance and detoxifying enzymes of B. tabaci from six representative locations exhibiting severe damage in Shandong. At four of the six locations, B. tabaci Mediterranean (MED) comprised 100% of the samples collected. In a further two locations, species composition was predominantly (>94%) MED with B. tabaci Middle East–Asia Minor 1 (MEAM1), comprising a low proportion (<6%) of the samples collected. For all field populations, avermectin was the most effective insecticide against adult B. tabaci , pyriproxyfen had a significant effect on B. tabaci eggs and field populations were susceptible to pymetrozine. Six field populations of B. tabaci have developed low-to-moderate resistance to neonicotinoids. The detoxifying enzyme activity of carboxylesterase, glutathione S -transferase, and multifunctional oxidase were quantified. Multifunctional oxidase and glutathione S -transferase activity were positively correlated with insecticide resistance in several B. tabaci populations. [ABSTRACT FROM AUTHOR]

Odorant binding proteins (OBPs) of insects play a critical role in chemical perceptions and choice of insect host plant. Bemisia tabaci is a notorious insect pest which can damage more than 600 plant species. In order to explore functions of OBPs in B. tabaci , here we investigated binding characteristics and function of odorant-binding protein 3 in B. tabaci (BtabOBP3). The results indicated that BtabOBP3 shows highly similar sequence with OBPs of other insects, including the typical signature motif of six cysteines. The recombinant BtabOBP3 protein was obtained, and the evaluation of binding affinities to tested volatiles of host plant was conducted, then the results indicated that β-ionone had significantly higher binding to BtabOBP3 among other tested plant volatiles. Furthermore, silencing of BtabOBP3 significantly altered choice behavior of B. tabaci to β-ionone. In conclusion, it has been demonstrated that BtabOBP3 exerts function as one carrier of β-ionone and the results could be contributed to reveal the mechanisms of choosing host plant in B. tabaci. [ABSTRACT FROM AUTHOR]

The ladybird beetle Serangium japonicum is an important predator of whiteflies. Investigations of the molecular mechanisms of this predatory beetle have been hindered by the scarcity of gene sequence data. To obtain gene sequences for the ladybird beetle and determine differences in gene expression between the summer and winter seasons, paired-end sequencing was performed. Real-time PCR was used to validate differences in Krueppel homolog 1 gene (Kr-h1) mRNA expression in summer vs. winter samples. To determined the diversity of the population, annotated cytochrome c oxidase subunit I gene (COX1) gene fragments were amplified from several ladybird beetle populations. The analysis yielded 191,246 assembled unigenes, 127,016 of which (66.4%) were annotated. These functional annotations of gene sequences are currently available from the National Center for Biotechnology Information (NCBI), and will provide a basis for studying the molecular mechanisms underlying the biological characteristics of S. japonicum. We found a change in expression of ribosome-associated genes across seasons, and postulate that this change is because of seasonal variation in temperature and photoperiod. The differential expression of Kr-h1 suggests that S. japonicum can successfully overwinter because the adults enter diapause. To explain the effects of season on Kr-h1 gene expression, we hypothesize a model in which that a short photoperiod affects the density of Ca2+, the subsequent activity of methyl farnesoate epoxidase and the synthesis of JH, and in turn Kr-h1 gene expression. COX1 annotation was concordant with the morphological ID. The same COX1 sequence was found in the samples from several provinces in China. Therefore, the COX1 sequence is worth further study to distinguish beetle species and populations. [ABSTRACT FROM AUTHOR]

For many crop pathogens including viruses, high genetic variation provides them with potential to adapt to and prevail in a changing environment. Understanding genetic variation in viruses and their significance is a key to elaborate virus epidemiology and evolution. While genetic variation of plant viruses has been documented to impact virus–host interactions, how it affects virus–insect vector interactions remains elusive. Here, we report the impact of mutations in the coat protein of squash leaf curl China virus (SLCCNV), a begomovirus, on the interaction between the virus and its whitefly vectors. We characterized mutations in the coat protein of SLCCNV and found that some residues exhibited higher mutation frequency than the others. We assayed the impact of mutation on infectivity using agroinoculation and found these mutations marginally affect virus infectivity. We further analyze their functions using virus acquisition and transmission trials and found some of mutations resulted in altered transmission of SLCCNV by different species of the whitefly Bemisia tabaci complex. We then identified the key amino acid residue(s) involved by constructing several mutant viruses and found that a single-residue mutation in the coat protein of SLCCNV was sufficient to significantly alter the whitefly transmission characteristics of SLCCNV. We examined the competition between different genotypes of SLCCNV in plant infection and whitefly transmission. We found that mutations in the coat protein did not alter the fitness of SLCCNV in plants, but they rendered the virus more competitive in transmission by certain species of whiteflies. Our findings indicate that mutations in the coat protein may play a key role in both the adaptation of begomoviruses to the changing vector populations and the evolution of begomoviruses. [ABSTRACT FROM AUTHOR]

Encarsia formosa Gahan is an important endoparasitoid of the whitefly, Bemisia tabaci Gennadius. In the present study, we compared the fitness and population parameters of E. formosa when parasitizing the two most invasive and destructive whitefly species in China, the B and Q of B. tabaci. We also studied whether natal host influenced on parasitism and host-feeding capacities of E. formosa on B. tabaci B versus Q. Age–stage life table analysis indicated that E. formosa developmental duration was shorter, fecundity was higher, and longevity was greater on B. tabaci B than on Q. The life table parameters, including the intrinsic rate of increase (r), finite rate of increase (λ), net reproduction rate (R 0), and the mean generation time (T), indicated that the fitness of E. formosa on B. tabaci B is higher than B. tabaci Q. We also found that the host species used to rear E. formosa affected the parasitoid's subsequent parasitism and host feeding on B. tabaci B and Q. When E. formosa were reared on B. tabaci B, its subsequent parasitism rate on third-instar nymphs was significantly higher on B. tabaci B than on Q. These results will be useful for managing the biological control of B. tabaci in the field. [ABSTRACT FROM AUTHOR]

Studying the spatial dynamics of pests allows the determination of abiotic and biotic factors affecting time and locations of pest attack to the crops. Such abiotic and biotic factors mainly include 1) climatic elements, 2) natural enemies, 3) phenological stage of plants, and 4) surrounding vegetation. Melon (Cucumis melo L. [Cucurbitales: Cucurbitaceae]) is among the most consumed fruit in the world, and the whitefly Bemisia tabaci (Gennadius) is among the main pests of this crop. This work aimed to determine the effects of surrounding vegetation, natural enemies, climatic elements, and stages of plants on the spatial dynamics of B. tabaci in commercial melon fields. Adult whitefly densities were monitored on four melon fields in a tropical climate region. Sampling location in crops was georeferenced. Experimental data were submitted to geostatistical analysis. The highest densities of B. tabaci occurred during hot periods experiencing lower rainfall, and when the surrounding area presented crops hosting B. tabaci , especially other melon farms. The density ratio of the predators (i.e. spiders and Geocoris sp.) were dependent on pest density. The pattern of field colonization by B. tabaci varies according to its density. Therefore, the surrounding vegetation, air temperature, and predators influence the spatial distribution of B. tabaci in melon fields. These results provide important information to melon farmers, assisting them to improve the management of B. tabaci in the field. [ABSTRACT FROM AUTHOR]

To further develop integrated pest management (IPM) strategies against two sucking insect pests, Aleurocanthus spiniferus (Quaintanca) (Hemiptera: Aleyrodidae) and Toxoptera aurantii Boyer (Hemiptera: Aphididae), in Chinese tea plantations, it is important to evaluate the effects of insecticides on biological control agents, such as the seven-spot lady beetle, Coccinella septempunctata L. (Coleoptera: Coccinellidae). Therefore, we tested the toxicity and sublethal effects of spirotetramat, clothianidin, lambda-cyhalothrin, and bifenthrin on C. septempunctata. The side effects of the active ingredients of the insecticides were evaluated with residual contact tests on the larvae of C. septempunctata in the laboratory. Spirotetramat and clothianidin exhibited lower lethality to C. septempunctata as shown by the higher LC50 values and had higher selectivity for A. spiniferus and T. aurantii based on the selective toxicity ratios being superior to other tested insecticides. Spirotetramat also did not affect survival, longevity, fecundity, and egg hatching of C. septempunctata. Clothianidin and bifenthrin prolonged the duration of larval development stages of C. septempunctata obviously. Clothianidin at >2.5 mg/liter, lambda-cyhalothrin at >0.03 mg/liter, and bifenthrin at >0.125 mg/liter significantly reduced the survival and pupation rates of C. septempunctata larvae. Furthermore, spirotetramat at 3.125 mg/liter was harmless (IOBC class 1) to larvae of this coccinellid species. Based on the results, spirotetramat was innocuous to C. septempunctata larvae compared with clothianidin, lambda-cyhalothrin, and bifenthrin. Therefore, spirotetramat might be incorporated into IPM programs in combination with C. septempunctata for control of A. spiniferus and T. aurantii in the tea plantations. [ABSTRACT FROM AUTHOR]

Members of the highly polyphagous Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) species complex cause major crop damage by feeding and by transmitting plant viruses. The Middle East-Asia Minor 1 (MEAM1) of the B. tabaci complex is by far the most problematic whitefly affecting crops including cultivated watermelon (Citrullus lanatus ; Cucurbitaceae: Cucurbitales). Watermelon cultivars share a narrow genetic base and are highly susceptible to whiteflies. We studied the potential of C. ecirrhosus , a perennial desert species that can be hybridized with C. lanatus , as a source of whitefly resistance for cultivated watermelon. The results of this study indicate that C. ecirrhosus offers resistance (although not total) against the MEAM1 B. tabaci based on, at least, antibiosis and antixenosis. Whitefly performance concerning developmental survival, body size attainment, and nonpreference were suppressed on C. ecirrhosus compared with the watermelon cultivar 'Sugar Baby'. Also, our olfactometer results indicated that the adults were less attracted to leaf volatiles of C. ecirrhosus. Although there is a pungent odor associated with the leaves of C. ecirrhosus , the leaf volatiles had no toxic effect on adult whitefly survival as compared with cultivated watermelon. We also demonstrated that plants of C. ecirrhosus can be clonally propagated from vine cuttings of the parent plant. Using traditional breeding procedures, C. ecirrhosus was hybridized with C. lanatus and viable F1 and F2 seeds were produced. This is the first report of pest resistance in C. ecirrhosus. This wild species offers a source of resistance against whiteflies for the improvement of cultivated watermelon. [ABSTRACT FROM AUTHOR]