O Tomato severe rugose virus (ToSRV) e o Tomato chlorosis virus (ToCV) estão entre as principais espécies de vírus que afetam a cultura do tomateiro atualmente no Brasil. Ambos possuem o mesmo vetor, a mosca-branca Bemisia tabaci MEAM1 (biótipo B), um inseto polífago e amplamente disseminado por todo país. Por este fato, infecções mistas destes vírus em lavouras de tomateiro são frequentes. No entanto, parâmetros epidemiológicos importantes para melhor compreensão das viroses associadas a esses vírus, quando em infecção simples ou mista em tomateiro, permanecem desconhecidos. Neste trabalho foram avaliados a cinética da invasão sistêmica e os períodos de latência e de incubação do ToSRV e do ToCV, em infecções simples e mista, em tomateiros. A cinética da invasão sistêmica foi analisada em tomateiros nos quais a folha inoculada foi destacada em diferentes intervalos de tempo após a inoculação. Os períodos de latência foram avaliados em tomateiros inoculados e que foram posteriormente utilizados como fontes de inóculo para a aquisição do(s) vírus por B. tabaci MEAM1, em ensaios de transmissão realizados em diferentes intervalos de tempo. Os períodos de incubação foram avaliados através da observação diária dos sintomas após a inoculação dos vírus nos tomateiros. O ToSRV e o ToCV iniciaram o movimento sistêmico em apenas um dia após a inoculação em tomateiro. Os períodos de latência do ToSRV, em infeções simples e mista, foram em média, 7 e 6 dias, respectivamente. Para o ToCV, os períodos médios de latência foram 13 dias em infecção simples e 11 dias em infecção mista. Os períodos de incubação do ToSRV, em infecções simples e mista, ocorreram, em média, 11 dias após os períodos de latência. O período de incubação do ToSRV foi influenciado pela idade da planta no momento da inoculação e também pela co-infecção com o ToCV. Os períodos de incubação do ToCV, em infecções simples e mista, ocorreram, em média, 17 e 20 dias após os períodos de latência, respectivamente. O início dos sintomas do ToCV não foi afetado pela idade da planta no momento da inoculação e nem pela co-infecção com o ToSRV. Estes resultados indicam que após a infecção o tomateiro rapidamente se torna uma fonte de inóculo do(s) vírus e passa a contribuir para a disseminação de ambos no campo. A defasagem de tempo entre os períodos de latência e de incubação do ToSRV e do ToCV nos tomateiros infectados revela que as plantas possibilitam a aquisição e subsequente transmissão dos vírus de um hospedeiro doente para um hospedeiro sadio antes de qualquer manifestação dos sintomas, fato que deve ser levado em consideração para o manejo destas fitoviroses no campo. / Tomato severe rugose virus (ToSRV) and Tomato chlorosis virus (ToCV) are among the main species of virus affecting tomato crops currently in Brazil. Both are transmitted by the same vector, the whitefly Bemisia tabaci MEAM1 (biotype B), a polyphagous insect widely disseminated throughout the country. Because of this fact, mixed infections of these viruses in tomato crops are frequent. However, important epidemiological parameters to better understand the diseases associated with these viruses, when in single or mixed infection in tomato, remain unknown. This study evaluated the kinetics of systemic invasion and latent and incubation periods of ToSRV and ToCV in single and mixed infections in tomato. The kinetics of systemic invasion was analyzed in tomato plants in which the inoculated leaf was detached at different time intervals after inoculation. The latent periods were evaluated in inoculated tomato plants which were later used as inoculum sources for the acquisition of ToSRV and/or ToCV by B. tabaci MEAM1, in transmission assays performed at different time intervals. Incubation periods were evaluated by daily observation of symptoms after inoculation of tomato plants. ToSRV and ToCV started the systemic movement just one day after inoculation in tomato plants. Average latent periods of ToSRV, in single and mixed infections, were 7 and 6 days, respectively. For ToCV, the average latent periods were 13 days in single infection and 11 days in mixed infection. ToSRV incubation periods, in single and mixed infections, occurred on average 11 days after the respective latent periods. The incubation period of ToSRV was influenced by the age of the plant at the time of inoculation and by the co-infection with ToCV. ToCV incubation periods, in single and mixed infections, occurred on average 17 and 20 days after the latent periods, respectively. The beginning of ToCV symptoms was not affected by the age of the plant at the time of inoculation or by co-infection with ToSRV. These results indicate that after infection, tomato plants rapidly become source of inoculum of the viruses and contribute to the dissemination of both in tomato crops. The mismatch between the latent and incubation periods of ToSRV and ToCV in infected tomato plants reveals that plants enable the acquisition and subsequent transmission of both viruses from a diseased to a healthy plant, prior to any manifestation of symptoms. Such knowlegment should be taken into consideration for the management of these viruses in tomato crops.

O Tomato chlorosis virus (ToCV), família Closteroviridae, gênero Crinivirus é um vírus de RNA de fita simples, senso positivo, transmitido de maneira semi-persistente por espécies da família Aleyrodidae, dos gêneros Bemisia e Trialeurodes. Possui uma gama de hospedeiros considerável que inclui plantas domesticadas e ervas daninhas das famílias Alzoaceae, Amaranthaceae, Apiaceae, Apocynaceae, Asteraceae, Plumbaginaceae, e Solanaceae. No estado de São Paulo, Brasil, foi relatado pela primeira vez em 2008, causando clorose internerval nas folhas de tomateiros. A importância desta doença emergente tem incrementado nos últimos anos e, no entanto, até o momento não existem estimativas dos danos causados nem alternativas adequadas para o manejo da doença no campo. Diante disso, esse trabalho teve como objetivos (i) avaliar a resistência de genótipos de tomateiro à infecção com o ToCV, (ii) avaliar a tolerância de alguns dos genótipos à doença e (iii) estimar o dano produzido em campo protegido. Para isso, 57 genótipos, incluindo espécies selvagens, linhagens avançadas e cultivares comerciais de tomateiro foram inicialmente avaliados quanto à resistência à infecção. Plantas jovens, produzidas em bandejas de poliestireno expandido, protegidas por gaiola recoberta com tecido de voil foram inoculadas por meio da liberação massal de B. tabaci MEAM1 virulífera para o ToCV. A incidência de plantas infectadas por genótipo foi determinada mediante observação dos sintomas e a detecção do vírus por RT-PCR. Alguns dos genótipos também foram avaliados quanto à tolerância à doença causada pelo crinivírus. Plantas sadias e sabidamente infectadas com o ToCV foram transplantadas no campo no interior de telados protegidos com tecido de voil. As plantas foram avaliadas quanto ao peso de frutos produzidos. No fim do ensaio, todas as plantas foram cortadas na região do colo e avaliaram-se os pesos fresco e seco da parte aérea. Em dois ensaios independentes de avaliação da resistência à infecção com o ToCV por meio da liberação massal de B. tabaci virulífera constatou-se que em condições de livre chance de escolha dos insetos os acessos Solanum peruvianum LA 444-1 e S. habrochaites PI 127826 e PI 134417 e as linhagens avançadas IAC 14-2-49+14-2-85 (somente no primeiro ensaio) e IAC 68F-22-2-24-1 não tiveram plantas infectadas, sugerindo alto grau de resistência à infecção pelo crinivírus. Para os demais genótipos avaliados a reação das plantas à infecção com o ToCV variou de moderadamente resistente à altamente suscetível. Dois ensaios independentes para avaliar a tolerância dos diferentes genótipos de tomateiro ao amarelão causado pelo ToCV, com base no desenvolvimento e na produção das plantas mostrou resultados bastante variáveis. Os resultados desse trabalho fornecerão subsídios para futuros trabalhos de melhoramento genético para o desenvolvimento de cultivares resistentes/tolerantes ao ToCV. / Tomato chlorosis virus (ToCV), family Closteroviridae, genus Crinivirus is a single-stranded, positive sense RNA virus, transmitted semi-persistently by species of the family Aleyrodidae, belonging to the genus Bemisia and Trialeurodes. ToCV infects several species including domesticated and weed plants belonging to the families Alzoaceae, Amaranthaceae, Apiaceae, Apocynaceae, Asteraceae, Plumbaginaceae and Solanaceae. In São Paulo, Brazil, this crinivirus was first reported in 2008, causing chlorosis in the leaves of tomato plants. The importance of this emerging disease has increased in recent years and yet, so far there are no estimates of the damage, nor suitable alternatives for the management of the disease in the field. Therefore, this study aimed to (i) evaluate the resistance of tomato genotypes to infection with ToCV, (ii) to evaluate the tolerance of some genotypes to the disease and (iii) estimate the damage produced in infected plants. Fifty seven genotypes, including wild species, hybrids and commercial tomato cultivars were initially evaluated for resistance to infection. Seedlings produced in expanded polystyrene trays protected by cage covered with voile fabric were inoculated through the mass release of ToCV viruliferous B. tabaci MEAM1. The incidence of infected plants per genotype was determined by observation of symptoms and virus detection by RT-PCR. Some of the genotypes were also evaluated for tolerance to the disease caused by the crinivirus. Healthy and ToCV infected plants were separately transplanted in the field, in cages protected with voile fabric. Weight of harvested fruits of the plants were evaluated. At the end of the test, all the plants were cut out and their fresh and dry weights were measured. Results from two independent trials showed that the accesses Solanum peruvianum LA 444-1, and S. habrochaites PI 127826 and PI 134417, and the hybrids IAC 14249+14285 and IAC 68F-22-2-24-1 did not have infected plants, suggesting a high degree of resistance to infection by the crinivirus. For all other genotypes the response of the plants to infection with ToCV ranged from moderately resistant to highly susceptible. Results from two independent trials to assess the tolerance of different tomato genotypes to the disease caused by ToCV, based on the development and production of the plants were widely variable. These findings provide insights for future breeding programs for the development of cultivars resistant and/or tolerant to ToCV.

Background: The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is among the 100 worst invasive species in the world. As one of the most important crop pests and virus vectors, B. tabaci causes substantial crop losses and poses a serious threat to global food security. Results: We report the 615-Mb high-quality genome sequence of B. tabaci Middle East-Asia Minor 1 (MEAM1), the first genome sequence in the Aleyrodidae family, which contains 15,664 protein-coding genes. The B. tabaci genome is highly divergent from other sequenced hemipteran genomes, sharing no detectable synteny. A number of known detoxification gene families, including cytochrome P450s and UDP-glucuronosyltransferases, are significantly expanded in B. tabaci. Other expanded gene families, including cathepsins, large clusters of tandemly duplicated B. tabaci-specific genes, and phosphatidylethanolamine-binding proteins (PEBPs), were found to be associated with virus acquisition and transmission and/or insecticide resistance, likely contributing to the global invasiveness and efficient virus transmission capacity of B. tabaci. The presence of 142 horizontally transferred genes from bacteria or fungi in the B. tabaci genome, including genes encoding hopanoid/sterol synthesis and xenobiotic detoxification enzymes that are not present in other insects, offers novel insights into the unique biological adaptations of this insect such as polyphagy and insecticide resistance. Interestingly, two adjacent bacterial pantothenate biosynthesis genes, panB and panC, have been co-transferred into B. tabaci and fused into a single gene that has acquired introns during its evolution. Conclusions: The B. tabaci genome contains numerous genetic novelties, including expansions in gene families associated with insecticide resistance, detoxification and virus transmission, as well as numerous horizontally transferred genes from bacteria and fungi. We believe these novelties likely have shaped B. tabaci as a highly invasive polyphagous crop pest and efficient vector of plant viruses. The genome serves as a reference for resolving the B. tabaci cryptic species complex, understanding fundamental biological novelties, and providing valuable genetic information to assist the development of novel strategies for controlling whiteflies and the viruses they transmit.

Bemisia tabaci (Genn.) is the vector of cassava mosaic geminiviruses (CMGs), which are the main production constraint to cassava, both in Uganda and elsewhere in Africa. A severe form of cassava mosaic disease (CMD) was responsible for the devastation of cassava in Uganda beginning in the late 1980s. In subsequent years the severe CMD epidemic spread throughout Uganda, and to neighbouring countries, causing devastating effects to cassava production, and its geographical range continues to expand with the pandemic. To further understand the virus-vector dynamics involved in the spread of CMD in the post epidemic zone in Uganda, we investigated the current distribution of B. tabaci genotypes in selected cassava-growing regions. Additionally, the relationship between the vector genotypes and distribution of CMGs in the post-epidemic zone was examined also. CMD-affected cassava leaves were collected from 3 to 5 month-old cassava plants, and B. tabaci adults and fourth instar nymphs were collected from cassava and twenty-two other plant species occurring adjacent to the sampled cassava fields. The mitochondrial cytochrome oxidase I (mtCOI) sequence was used to establish the genotype of B. tabaci adults and nymphs associated with the sampled plant species. African cassava mosaic virus (ACMV) and East African cassava mosaic virus-Uganda 2 (EACMV-UG2) were confirmed to be present in the post-epidemic zone in Uganda, as reported previously. As expected, EACMV-UG2 predominated. However, unlike previous observations in which EACMV-UG2 was consistently associated with the severe disease phenotype, in this study EACMV-UG2 occurred almost equally in the severely and mildly diseased plants. Phylogenetic analyses of Ugandan B. tabaci genotypes (mtCOI) revealed that their closest relatives were other Old World genotypes, as might be expected. Two previously reported B. tabaci genotype clusters, Uganda 1 (Ug1) and Uganda 2 (Ug2), at ~8% nt divergence, were confirmed to occur on cassava in the post-epidemic zone. However, Ug1 occurred more frequently (83%) than Ug2 (17%), and no definite association was established of a particular vector genotype with cassava plants exhibiting the severe disease phenotype, in contrast to the B. tabaci genotype distribution and association with the CMGs reported there at the height of the spread of the severe CMD epidemic. Based on the presence of B. tabaci fourth instar nymphs, the Ug1 genotypes colonized five additional non-cassava plant species: Manihot glaziovii, Jatropha gossypifolia, Euphorbia heterophylla, Aspilia africana and Abelmoschus esculentus, suggesting that in Uganda the Ug1 genotypes are not restricted to cassava. However, no Ug2 genotypes were detected on the non-cassava plant species sampled. This study revealed also the presence in Uganda of five distinct previously unrecorded B. tabaci genotype clusters, Uganda 3 (Ug3), Uganda 4 (Ug4), Uganda 5 (Ug5), Uganda 6 (Ug6) and Uganda 7 (Ug7), and a sweetpotato colonizing genotype cluster, designated Uganda 8 (Ug8), among the collective Ugandan B. tabaci populations. Ug3 was the only exemplar representing one cluster, which was unlike any previously described genotype in Uganda or elsewhere, and diverged at 8%, 10% and 17% from Ug1, Ug2 and Ug8, respectively. The Ug3 genotypes colonized a single species, Ocimum gratissimum. Ug4, Ug5, Ug6 and Ug7 formed four closely related sub-clusters (93-97% nt identity), and diverged from one another by 1-7%, and by 15-18% from Ug1, Ug2, Ug3 and Ug8, respectively. The Ug4 genotypes had as their closest relatives (at 97-99% nt identity) previously reported B. tabaci from okra in the Ivory Coast, whereas, the Ug5 and Ug6 genotypes shared 95-99% and 99% nt identity, respectively, with their closest relatives from the Mediterranean-North Africa- Middle East (MED-NAFR-ME) region, which also includes the well studied B and Q biotypes. The Ug7 genotypes were closely related (at 98-99% nt identity) to B. tabaci from Reunion Island in the Indian Ocean. The Ug4, Ug5, Ug6 and Ug7 genotypes were identified on 54%, 8%, 8%, and 31% of the sampled plants species, respectively. Ug4 were most polyphagous, followed by Ug7 and Ug6. However, none of the new five genotypes (Ug3-Ug7) was found associated with, or colonizing, xx cassava or sweetpotato plants in this study. Squash plants colonized by the Ug6 and Ug7 genotypes, both members of the B biotype/B-like cluster, developed the silvering phenotype, while those colonized by the Ug4 genotypes (most closely related to a non-B like genotype from okra in the Ivory Coast) did not. In addition to colonizing sweetpotato, the Ug8 genotypes also colonized Lycopersicon esculentum and L nepetifolia.

University, Diss., 2001--Bonn.

The Bemisia tabaci (Gennadius) sibling species group is known to comprise several morphologically undistinguishable mitotypes which can be separated into seven major phylogeographic clades using the 3' half of the mitochondrial cytochrome oxidase I gene. B. tabaci is the only vector of begomoviruses; it transmits the complex of viruses that cause the cotton leaf curl disease, which has rapidly spread from Pakistan to the Philippines, at southeast of Asia, in the last decade. The study of B. tabaci mitotypes has been limited to variants of worldwide distribution and those associated to agroecosystems, however, the study of indigenous mitotypes has been scarce. This dissertation provides a comprehensive study of the phylogeography and population biology of mitotypes belonging to two major phylogeographic clades, the Asia II and the Americas. The Asia II major clade contains the highest number of mitotypes, in contrast, there is a large gap in knowledge about mitotypes associated to highly endemistic niches in the Americas. To study the population biology of mitotypes belonging to the Asia II major phylogeographic clade, two fragments of the mtCOI gene were amplified by polymerase chain reaction (PCR) for adult whiteflies sampled from mono and multi-cropping systems in the provinces of Punjab and Sindh in Pakistan. Phylogenetic analyses suggested that three indigenous mitotypes were distinctively distributed across ecosystems of Pakistan. The Asia II-5 and II-7 were found restricted to multi-cropping systems of Lahore, while the Asia II-1 was found widespread throughout the cotton growing region of Pakistan. Moreover, population analyses suggested the Asia II-1 is undergoing demographic expansion following a recent selective sweep or bottleneck. This event explains the predominance of Asia II-1 in Pakistan and its spread towards the southern province of Sindh. Additionally, differences in DNA polymorphism and diversity between mtCOI fragments derived in dissimilar evolutionary pairwise distances, suggestive of future implications in the “species” delimitation at a global scale when choosing one fragment over the other. The endosymbiotic bacteria assemblages associated to indigenous mitotypes Asia II-1, II-5 and II-7 were studied by analysis of 16S rRNA profiles. Besides the primary symbiont Portiera, Arsenophonus was detected almost fixed in the studied populations and several unique strains of Arsenophonus were detected in Asia II-5 and II-7, suggesting possible unique environmental adaptation capacities of these mitotypes. Hierarchical clustering of 16S rRNA profiles, proposed host-based and environmental-related differentiation. Additionally, the disruption of parallel cladogenesis between the primary symbiont and B. tabaci, disallows rejection of the hypothesis that gene flow among B. tabaci mitotypes occurs. To study the population biology of indigenous mitotypes belonging to the Americas major clade, adult whiteflies were sampled from ecosystems of nine provinces in Ecuador. Based on phylogenetic analyses, three indigenous and one invasive mitotype were detected. Among the indigenous, a previously unrecognized mitotype, named ECU3, was found. Moreover, mitotypes were found coexisting in five locations, and the invasive B is thought to have displaced endemic mitotypes to the northern and eastern coastal habitats of Ecuador.

Made available in DSpace on 2016-08-12T19:18:24Z (GMT). No. of bitstreams: 1 ALAN MARTINS DE OLIVEIRA.pdf: 1485830 bytes, checksum: 11c6b8c6119b924bac2704d8a0abf2f0 (MD5) Previous issue date: 2008-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work aims to analyze technical and environmental aspects of the production of melon in the Homogeneous Zone in Mossoró emphasizing the fitosanitary control of the whitefly and Leaf Miner Fly. It is divided in two parts. In the Chapter I, an experiment was installed in Baraúna-RN, using delineation in blocks at random, in pieces subdivided in the time 6 x 5. There were six treatments in the piece: 1-physical control (blanket) chemist; 2-physical control (manta) + natural (oil of neem); 3-physical control (manta) + chemist + natural + peat (oil of neem); 4-physical control (manta) + chemist + peat + biological (trichoderma); 5-chemical control; 6-testifies. There were five times of evaluation in the sub piece of pest infestation: 20°, 28°, 36°, 44° and 52° DAT Days After the transplanting. Quantitative characteristics were analyzed: counting of nymphs and adults of whitefly and, larvae and adults of Leaf Miner Fly; qualitative characteristics in the fruits: mass, soluble solids, pulp firmness and pH. The use of alternative methods: biological, physical, natural control and peat have positive effects when used in the associate form. So, it is possible to reduce the use of pesticides in the melon. In the Chapter II, it was used like methodological proceedings the exploratory and descriptive search. There were valued data of questionnaires devoted to the owners or managers of the producing enterprises of melon, through probabilistic sample. It was checked that the short cycle of the culture, the model based on the monoculture, the agricultural mechanization, the elevated consumption of energy and the use of pesticides and chemical fertilizers associated to the marketing demands of qualitative and quantitative characteristics of the results, are affecting the sustainability of the culture of melon. In the final considerations, we realize that the technologies and the developed methods of production, aiming to pay attention to the growing demand of the result, especially of the rich countries, are untenable in the environmental optics; besides proposing larger searches aiming the sustainability: economical growth with ecological care and social equity / Este trabalho objetiva analisar aspectos técnicos e ambientais da produção de melão na Zona Homogênea Mossoroense, com ênfase ao controle fitossanitário das mosca-branca e mosca-minadora. Está dividido em duas partes. No Capítulo I, instalou-se um experimento em Baraúna-RN, usando delineamento em blocos ao acaso, em parcelas subdivididas no tempo 6 x 5. Na parcela constaram seis tratamentos: 1- controle físico (manta) + químico; 2- controle físico (manta) + natural (óleo de nim); 3- controle físico (manta) + químico + turfa + natural (óleo de nim); 4- controle físico (manta) + químico + turfa + biológico (trichoderma); 5- controle químico; 6- testemunha. Na subparcela constaram cinco tempos de avaliação de infestação de pragas: 20º, 28°, 36°, 44° e 52° DAT Dias Após o Transplantio. Analisaram-se características quantitativas: contagem de ninfas e adultos de mosca-branca e, larvas e adultos de mosca-minadora; características qualitativas nos frutos: massa, sólidos solúveis, firmeza de polpa e pH. O uso de métodos alternativos: controle biológico, físico, natural e turfa têm eficiência quando usados de forma associada. Assim, é possível reduzir o uso de agrotóxicos no melão. No Capítulo II, utilizou-se como procedimentos metodológicos a pesquisa exploratória e descritiva. Avaliou-se dados de questionários aplicados aos proprietários ou gestores das empresas produtoras de melão, por meio de amostragem probabilística. Verificou-se que o ciclo curto da cultura, o modelo baseado na monocultura, a mecanização agrícola, o elevado consumo de energia e o uso de agrotóxicos e fertilizantes químicos, associados às exigências mercadológicas de características quali-quantitativas dos frutos, estão afetando a sustentabilidade da atividade meloeira. Nas considerações finais, destaca-se que as tecnologias e os métodos de produção desenvolvidos, visando atender à crescente demanda do fruto, notadamente dos países ricos, são insustentáveis na ótica ambiental; além de propor pesquisas mais abrangentes quanto aos princípios norteadores da sustentabilidade: crescimento econômico com prudência ecológica e eqüidade social

Les invasions biologiques ont des conséquences écologiques telles que l'émergence de pathogènes et de ravageurs. Les populations invasives font face à de nouvelles conditions biotiques et abiotiques qu'elles doivent surmonter. Ces invasions biologiques sont des systèmes modèles pour étudier l'évolution sur de courtes échelles de temps car elles nécessitent une adaptation rapide qui fait intervenir différents processus (sélection naturelle, dérive, plasticité phénotypique). Du fait des introductions multiples et de l'hybridation, une augmentation de la variabilité génétique nucléaire peut-être observée dans ces populations, support d'une réponse adaptative plus rapide. De plus, chez les insectes, les symbiotes peuvent jouer un rôle important dans l'adaptation, contribution encore largement inconnue. Le ravageur de culture Bemisia tabaci est un complexe d'espèces dont les barrières reproductives sont peu connues et dont les différentes entités --- les cytotypes --- présentent des cortèges symbiotiques qui leur sont spécifiques. Grâce à une description de la dynamique spatio-temporelle de ces cytotypes, en contexte invasif en France et plus largement dans le bassin méditerranéen, nous avons constaté la présence simultanée de deux de ces entités et nous nous sommes interrogés sur un éventuel remplacement ou une coexistence. Cette situation originale nous a permis de tester leurs limites reproductives grâce à des microsatellites et des tests comportementaux, ainsi que la possibilité de transferts horizontaux de bactéries. Transferts que nous avons tenté de reproduire en laboratoire. Nous avons aussi développé des marqueurs RADSeq pour de futures analyses génomiques / Biological invasions have ecological consequences such as the emergence of pathogens and pests. Invasive populations face new biotic and abiotic conditions that they have to overcome.These biological invasions are model systems to study the evolution over short time scales because they require rapid adaptation that involves different processes (natural selection, drift, phenotypic plasticity).Because multiple introductions and hybridization, an increase in the nuclear genetic variability may be observed in these populations, supporting a faster adaptive response.Moreover, in insects, symbionts can play an important role in adaptation, a contribution largely unknown yet.Bemisia tabaci crop pest is a complex of species whose reproductive barriers are poorly known and whose different entities --- the cytotypes --- have symbiotic associations specific to them.Through a spatio-temporal dynamics description of these cytotypes in invasive context in France and more widely in the Mediterranean bassin, we found the simultaneous presence of both of these entities and we wondered about a possible replacement or coexistence.This peculiar situation has allowed us to test their reproductive boundaries with microsatellites and behavioral tests, as well as the possibility of horizontal transfer of bacteria. Transfers that we tried to reproduce in the laboratory. We have also developed RADSeq markers for future genomic analyzes

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biotype B is a cosmopolitan, devastating insect pest due to their direct damages and transmission of plant viruses. Entomopathogenic fungi comprise the most diverse group of pathogens regulating arthropod pest populations in agroecosystems. Anamorphic fungal entomopathogens, including Beauveria bassiana, Isaria fumosorosea, and Lecanicillium spp., are among the main biocontrol agents of whitefly populations. Advances in research focusing on virulence, mass production, formulation, and storage stability of fungal propagules are imperative for the development of efficient mycopesticides toward whiteflies and other soft-bodied insects. Therefore, this study placed emphasis on screening for virulent fungal strains, enhancement of efficacy using nonionic surfactants in spray tank-mix, development of liquid culture conditions for rapid production and stabilization processes of single-yeast like cells known as blastospores. Firstly, we selected virulent strains of B. bassiana and I. fumosorosea displaying fastest speed of kill and inciting highest mortality levels of whitefly nymphs and adults along with their ability to produce high numbers of conidia on moistened parboiled rice. Secondly, insecticidal performance was enhanced by combining nonionic surfactants with spore suspensions rendering additive or synergistic effects. These surfactants also allowed reducing the volume application rate without altering fungal bioefficacy. Results from liquid fermentation studies using B. bassiana and I. fumosorosea revealed that appropriate amounts of inexpensive ingredients, such as cottonseed flour and glucose, are suitable for the rapid production of high yields of blastospores (3 days pre-culture and 2-3 days culture). The resultant blastospores of various strains survived well to desiccation and remained viable for more than one year under refrigeration. Moreover, these air-dried blastospores of both fungal species showed higher virulence against whitefly nymphs when compared with solid-substrate produced conidia. Optimized liquid culture production for B. bassiana blastospores was also achieved through the manipulation of oxygen rates and osmotic pressure in the liquid media. Furthermore, these blastospores produced in highly aerated and hyperosmotic liquid medium containing 140 g glucose L-1 were also more virulent to whitefly nymphs than those cells derived from low-osmotic medium amended with 40 g glucose L-1. These optimal conditions were also scaled up in 5-L bioreactor that yielded 1-2 × 1012 viable blastospores L-1 in 6 days at a cost of US$ 0.19 L-1. These blastospores were formulated with diatomaceous earth for air drying or for spray drying. Formulated blastospores of B. bassiana survived dehydration using both drying methods and showed improved shelf life when stored under vacuumpackaged at 4 °C rather than 28 °C. However, when these blastospores were actively packaged with dual action oxygen-moisture scavenging system, blastospores showed prolonged stability for up to 7 months at 28 °C and still remained virulent to whiteflies. Therefore, this low-cost production and stabilization method for the rapid production of shelf stable, virulent blastospores of B. bassiana and I. fumosorosea may expand the commercial use of mycopesticides for insect control in mainstream agriculture. / A mosca-branca, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biótipo B, é uma praga cosmopolita e devastadora devido aos prejuízos oriundos dos seus danos diretos e transmissão de vírus. Fungos entomopatogênicos compreendem um grupo diversificado, que desempenha ação importante na regulação de populações de praga em agroecossistemas. Fungos ascomicetos anamórficos, como Beauveria bassiana, Isaria fumosorosea e Lecanicillium spp., constituem relevantes agentes de biocontrole de moscas-brancas. Avanços na pesquisa focando virulência, produção massal, formulação e estabilização de propágulos fúngicos são fundamentais para o desenvolvimento de micopesticidas eficientes contra moscas-brancas e outros insetos. Desta forma, este trabalho objetivou selecionar isolados fúngicos virulentos à mosca-branca; aumentar a eficácia mediante uso de surfactants não-iônicos em suspensões conidiais; desenvolver meios de cultura para produção rápida e estável por fermentação líquida submersa de células leveduriformes conhecidas por blastosporos. Na primeira etapa, isolados virulentos de B. bassiana e I. fumosorosea foram selecionados pela rápida e elevada atividade inseticida a ninfas e adultos de mosca-branca, bem como alto rendimento de conídios em arroz parboilizado. A adição de surfactantes organosiliconados permitiu a redução do volume de calda aplicado com resultados aditivos ou sinérgicos de controle. Foi ainda verificado que altos rendimentos de blastosporos tanto de B. bassiana como I. fumosorosea foram obtidos em curto tempo de fermentação líquida (3 dias de précultivo e 2-3 dias de cultivo) usando nutrientes de baixo custo, como glucose e farelo de algodão. Esses blastosporos foram tolerantes à dessecação e mantiveram viabilidade por mais de um ano sob refrigeração (4 °C). Os blastosporos foram mais virulentos que conídios aéreos, o que coloca esta estrutura como a mais indicada como ingrediente ativo em bioinseticidas para moscas-brancas. Mediante manipulação nutricional e física do ambiente de fermentação, a produção de blastosporos de B. bassiana foi optimizada mediante aumento da aeração e pressão osmótica do meio líquido. Blastosporos produzidos em meio líquido altamente aerado e hiperosmótico (140 g glucose L-1) mostraram-se mais virulentos à mosca-branca em relação àqueles produzidos em meio hipo-osmótico (40 g glucose L-1). Esse processo foi reproduzido em escala piloto usando biorreator de 5 L resultando numa produção de 1-2 × 1012 blastosporos viáveis L-1 em apenas 3 dias a um custo de US$ 0,19 L-1. Blastosporos de B. bassiana formulados com terra de diatomáceas e secados em fluxo de ar contínuo, ou secados em spray dryer tiveram estabilidade extendida por até 8 meses a 4 °C e superior em relação a 28 °C. Durante empacotamento, o uso de sachês absorventes de oxigênio e umidade prolongou consideravelmente a viabilidade de blastosporos armazenados a 28 °C por até 7 meses sem afetar sua eficiência contra mosca-branca. Em suma, esses resultados demonstram a viabilidade técnica e econômica de produção de blastosporos virulentos de B. bassiana e I. fumosorosea, tolerantes à dessecação e estáveis durante armazenamento. Esta tecnologia é uma nova opção que pode contribuir para expansão comercial de bioinseticidas à base de fungos entomopatogênicos.

Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biotype B is a cosmopolitan, devastating insect pest due to their direct damages and transmission of plant viruses. Entomopathogenic fungi comprise the most diverse group of pathogens regulating arthropod pest populations in agroecosystems. Anamorphic fungal entomopathogens, including Beauveria bassiana, Isaria fumosorosea, and Lecanicillium spp., are among the main biocontrol agents of whitefly populations. Advances in research focusing on virulence, mass production, formulation, and storage stability of fungal propagules are imperative for the development of efficient mycopesticides toward whiteflies and other soft-bodied insects. Therefore, this study placed emphasis on screening for virulent fungal strains, enhancement of efficacy using nonionic surfactants in spray tank-mix, development of liquid culture conditions for rapid production and stabilization processes of single-yeast like cells known as blastospores. Firstly, we selected virulent strains of B. bassiana and I. fumosorosea displaying fastest speed of kill and inciting highest mortality levels of whitefly nymphs and adults along with their ability to produce high numbers of conidia on moistened parboiled rice. Secondly, insecticidal performance was enhanced by combining nonionic surfactants with spore suspensions rendering additive or synergistic effects. These surfactants also allowed reducing the volume application rate without altering fungal bioefficacy. Results from liquid fermentation studies using B. bassiana and I. fumosorosea revealed that appropriate amounts of inexpensive ingredients, such as cottonseed flour and glucose, are suitable for the rapid production of high yields of blastospores (3 days pre-culture and 2-3 days culture). The resultant blastospores of various strains survived well to desiccation and remained viable for more than one year under refrigeration. Moreover, these air-dried blastospores of both fungal species showed higher virulence against whitefly nymphs when compared with solid-substrate produced conidia. Optimized liquid culture production for B. bassiana blastospores was also achieved through the manipulation of oxygen rates and osmotic pressure in the liquid media. Furthermore, these blastospores produced in highly aerated and hyperosmotic liquid medium containing 140 g glucose L-1 were also more virulent to whitefly nymphs than those cells derived from low-osmotic medium amended with 40 g glucose L-1. These optimal conditions were also scaled up in 5-L bioreactor that yielded 1-2 × 1012 viable blastospores L-1 in 6 days at a cost of US$ 0.19 L-1. These blastospores were formulated with diatomaceous earth for air drying or for spray drying. Formulated blastospores of B. bassiana survived dehydration using both drying methods and showed improved shelf life when stored under vacuumpackaged at 4 °C rather than 28 °C. However, when these blastospores were actively packaged with dual action oxygen-moisture scavenging system, blastospores showed prolonged stability for up to 7 months at 28 °C and still remained virulent to whiteflies. Therefore, this low-cost production and stabilization method for the rapid production of shelf stable, virulent blastospores of B. bassiana and I. fumosorosea may expand the commercial use of mycopesticides for insect control in mainstream agriculture. / A mosca-branca, Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae) biótipo B, é uma praga cosmopolita e devastadora devido aos prejuízos oriundos dos seus danos diretos e transmissão de vírus. Fungos entomopatogênicos compreendem um grupo diversificado, que desempenha ação importante na regulação de populações de praga em agroecossistemas. Fungos ascomicetos anamórficos, como Beauveria bassiana, Isaria fumosorosea e Lecanicillium spp., constituem relevantes agentes de biocontrole de moscas-brancas. Avanços na pesquisa focando virulência, produção massal, formulação e estabilização de propágulos fúngicos são fundamentais para o desenvolvimento de micopesticidas eficientes contra moscas-brancas e outros insetos. Desta forma, este trabalho objetivou selecionar isolados fúngicos virulentos à mosca-branca; aumentar a eficácia mediante uso de surfactants não-iônicos em suspensões conidiais; desenvolver meios de cultura para produção rápida e estável por fermentação líquida submersa de células leveduriformes conhecidas por blastosporos. Na primeira etapa, isolados virulentos de B. bassiana e I. fumosorosea foram selecionados pela rápida e elevada atividade inseticida a ninfas e adultos de mosca-branca, bem como alto rendimento de conídios em arroz parboilizado. A adição de surfactantes organosiliconados permitiu a redução do volume de calda aplicado com resultados aditivos ou sinérgicos de controle. Foi ainda verificado que altos rendimentos de blastosporos tanto de B. bassiana como I. fumosorosea foram obtidos em curto tempo de fermentação líquida (3 dias de précultivo e 2-3 dias de cultivo) usando nutrientes de baixo custo, como glucose e farelo de algodão. Esses blastosporos foram tolerantes à dessecação e mantiveram viabilidade por mais de um ano sob refrigeração (4 °C). Os blastosporos foram mais virulentos que conídios aéreos, o que coloca esta estrutura como a mais indicada como ingrediente ativo em bioinseticidas para moscas-brancas. Mediante manipulação nutricional e física do ambiente de fermentação, a produção de blastosporos de B. bassiana foi optimizada mediante aumento da aeração e pressão osmótica do meio líquido. Blastosporos produzidos em meio líquido altamente aerado e hiperosmótico (140 g glucose L-1) mostraram-se mais virulentos à mosca-branca em relação àqueles produzidos em meio hipo-osmótico (40 g glucose L-1). Esse processo foi reproduzido em escala piloto usando biorreator de 5 L resultando numa produção de 1-2 × 1012 blastosporos viáveis L-1 em apenas 3 dias a um custo de US$ 0,19 L-1. Blastosporos de B. bassiana formulados com terra de diatomáceas e secados em fluxo de ar contínuo, ou secados em spray dryer tiveram estabilidade extendida por até 8 meses a 4 °C e superior em relação a 28 °C. Durante empacotamento, o uso de sachês absorventes de oxigênio e umidade prolongou consideravelmente a viabilidade de blastosporos armazenados a 28 °C por até 7 meses sem afetar sua eficiência contra mosca-branca. Em suma, esses resultados demonstram a viabilidade técnica e econômica de produção de blastosporos virulentos de B. bassiana e I. fumosorosea, tolerantes à dessecação e estáveis durante armazenamento. Esta tecnologia é uma nova opção que pode contribuir para expansão comercial de bioinseticidas à base de fungos entomopatogênicos.