Made available in DSpace on 2014-06-11T19:35:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-12-07Bitstream added on 2014-06-13T20:45:43Z : No. of bitstreams: 1 albuquerque_fa_dr_botfca.pdf: 1798197 bytes, checksum: 60366c6885a9cad436dbac48035038c5 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Com o objetivo de identificar as possíveis espécies de tripes associadas à cultura do milho, a espécie predominante, a proporção de adultos e ninfas, a época de ocor-rência, o período crítico de ataque e a influência do sistema de plantio e das condições climáti-cas sobre a população de tripes e métodos de amostragem, foram conduzidos ensaios na Fa-zenda Experimental de Iguatemi, localizada no Município de Maringá, PR, no período de ou-tubro de 2001 a fevereiro de 2004. As avaliações foram realizadas por meio da coleta de tri-pes com armadilhas adesivas azuis e coletando-se plantas de milho, cortadas rente ao solo, colocadas em sacos plásticos e levadas ao laboratório, onde foram lavadas em álcool 70%, para extração dos tripes. A determinação dos danos provocados pelo tripes foi estudada em cinco experimentos inteiramente casualizados, correlacionando diferentes níveis populacionais de tripes e produtividade. Foi empregado o inseticida thiamethoxan, em tratamento de semen-tes, e pulverizações com metamidofós, em diferentes estágios de desenvolvimento das plantas, para obter parcelas com diferentes níveis de incidência de tripes em períodos pré-determinados. Foram identificadas oito espécies de tripes associadas à cultura do milho, na região, sendo Frankliniella williamsi Hood, 1915, a mais freqüente (99,43%). Verificou-se que a incidência de tripes na cultura de milho em solo coberto com aveia dessecada foi menor do que em solo nu, ou coberto por aveia tombada ou incorporada, sendo que imediatamente após a emergência das plantas a população de tripes era composta quase que exclusivamente por adultos imigrantes. A população de formas jovens começou a aumentar a partir dos 14 dias após a emergência das plantas, indicando a capacidade reprodutiva do tripes na cultura do milho. Foi verificada correlação negativa entre... . / Aiming to identify the possible species of thrips associated to the corn crop, the predominant species, the adult/nymph rate, occurrence time, critical period of attack, influence of the sowing system and climatic conditions on the population of thrips and sampling methods, essays were carried out at the Experimental Farm of Iguatemi, in Maringá, Paraná State, Brazil, from October 2001 to February 2004. The evaluations consisted in collecting thrips with blue adhesive traps and collecting corn plants cuted at soil level, placed into plastic bags and took to the laboratory, where they were washed in alcohol 70%, for the extraction of thrips. The determination of the damages caused by thrips was studied in five experiments, totally randomized, correlating different population levels of thrips and productivity. The insecticide thiamethoxan was applied in seed treatment and methamidophos, in sprayings in different stages of plant development to obtain areas with different levels of incidence of thrips in periods previously established. Eight species of thrips associated to corn crop were identified in the area, being Frankliniella williamsi Hood, 1915, the most frequent (99.43%). It was verified that the incidence of corn thrips in soil covered with dried oats was smaller than in nude soil or in soils covered by cuted or incorporated oat, considering that, immediately after the plants emergence, the population of thrips was composed almost exclusively by emigrant adults. The young population began to increase from 14 days after plant emergence, on indicating thrips reproductivity capacity in corn crops. Negative correlation was verified between the rainfall index and the number of thrips collected in blue traps, but it was not observed any correlation among the number of thrips by corn plant and the number of thrips collected in those traps. It was verified that more than 30 thrips... (Complete abstract, click electronic address below).

Thrips are major agricultural pests throughout much of the United States. More information is needed about sampling methods, management practices, and insecticide susceptibility to help better control this pest. A two year survey was conducted to determine the species present in southeast Virginia and the population characteristics of those species. Thrips were monitored using yellow sticky traps. Tobacco thrips, Frankliniella fusca, were the most abundant species. In general thrips populations began to build up beginning in April, peaked in August, and then started to decline. Differences in this trend were observed between species. A study was conducted in seedling soybean to evaluate the within-plant location of thrips, whether a plant subsample could be used for thrips monitoring, and to determine the thrips species complex present. Soybean thrips, Neohydatothrips variabilis, were the most prominent species present. The greatest density of thrips larvae was located in the terminal bud of the seedling and suggests that immature thrips aggregate. Neither of the proposed subsamples of plant material explained the variability in immature thrips numbers and at this time we recommend whole-plant sampling for obtaining the most accurate estimate of thrips populations in seedling soybean. Tobacco thrips, F. fusca, as well as a complex of other thrips species attack cotton and peanut seedlings and can cause significant yield loss to these crops in the mid-Atlantic U.S. Experiments were conducted in these two crops to assess the efficacy of a novel diamide insecticide cyantraniliprole applied as a liquid in-furrow at planting and post-plant emergence broadcast spray treatment to control thrips. In both cropping systems cyantraniliprole significantly reduced the number of immature thrips and reduced thrips feeding injury to the plants. In several instances cyantraniliprole treatments resulted in increased yield as compared to the non-insecticide treated control and yields which were statistically similar to those obtained with standard thrips control insecticides. Laboratory bioassays were conducted to evaluate the toxicity (LC50 values) of cyantraniliprole and two conventional insecticides against F. fusca adults. Results of these assays were inconclusive. At times F. fusca adults were susceptible to the insecticides, but the results could not be replicated consistently. / Master of Science

O presente trabalho apresenta um estudo detalhado da morfologia comparada do sistema digestivo de espécies representantes das ordens Hemiptera e Thysanoptera, numa perspectiva evolutiva, tendo como foco principal a análise da organização do complexo luminal de membranas existente no intestino médio dessas espécies, cuja presença no intestino médio constitui uma das características mais peculiares encontradas nestes grupos de insetos. As espécies das ordens Hemiptera e Thysanoptera compreendem o chamado grupo dos Condylognatha que reúne organismos com hábitos alimentares diversos, mas predominantemente sugadores. A grande maioria dos insetos apresenta, no interior do intestino médio, um estrutura luminal quitino-proteica denominada de membrana peritrófica, que, entre outras funções, compartimentaliza o processo digestivo. No entanto, nos membros do grupo Condylognatha esta estrutura está ausente, sendo substituída por um complexo membranoso bastante elaborado, associado às microvilosidades dos enterócitos, denominado de complexo luminal de membranas. Existem, basicamente, três tipos de complexos luminais descritos na literatura: as membranas perimicrovilares (MPM), as membranas perimicrovilares modificadas (MPMm) e as membranas luminais em forma de chama (MLC). As primeiras descrições deste complexo, do tipo MPM, foram feitas em hemípteros da subordem Heteroptera. No entanto, a presença deste tipo de complexo também foi notada em espécies de Thysanoptera, sugerindo uma origem evolutiva das MPM a partir de um ancestral comum dos Condylognatha, como uma adaptação ao hábito alimentar sugador de seiva. Estudos posteriores evidenciaram a ocorrência dos demais tipos de complexo em membros das outras subordens de Hemiptera, as MPMm em Sternorrhyncha e, mais recentemente, as membranas luminais em forma de chama MLC em Auchenorrhyncha, o que sugerem ser essa estrutura luminal muito mais diversa morfologicamente do que se acreditava inicialmente. Neste contexto, o foco principal deste trabalho foi realizar um estudo morfofuncional comparativo do sistema digestivo em representantes de Condylognatha, com o objetivo principal de se detectar os tipos de complexo luminal de membranas presentes e descrever detalhes de sua organização. Para isso, foram realizados estudos anatômicos, histológicos e ultraestruturais do sistema digestivo das espécies selecionadas, incluindo técnicas de microscopia eletrônica de transmissão, varredura e de fluorescência confocal. Assim, foram utilizadas três espécies de Hemiptera, subordem Auchenorrhyncha: Dalbulus maidis (Cicadellidae) e Mahanarva fimbriolata (Cercopidae) que pertencem à infraordem Cicadormorpha, e Peregrinus maidis (Delphacidae), da infraordem Fulgoromorpha. Além disso, foram estudados três representantes de Thysanoptera: Frankliniella schultzei (Thripidae), Franklinothrips vespiformes (Aeolothripidae), Leucothrips furcatus (Dendothripinae) e Liothrips sp. (Phlaeothripinae), sendo as três primeiras integrantes da subordem Terebrantia e a última, Tubulifera. Os resultados obtidos revelaram que as espécies M. fimbriolata e D. maidis possuem um complexo luminal muito semelhante ao do tipo MLC. Por sua vez, o complexo luminal membranas da espécie P. maidis revelou-se bastante diferente das outras espécies conhecidas de Auchenorrhyncha, que pode ser considerado uma modificação do modelo MLC. Neste caso, destaca-se a presença de uma camada membranosa eletrondensa aparentemente revestindo todo o complexo de membranas em sua face voltada para a luz do intestino. Diferenças significativas foram observadas na arquitetura do complexo luminal entre as espécies analisadas de Thysanoptera. Enquanto que nas espécies F. schultzei e F. vespiformes observa-se um complexo luminal de membranas similar ao tipo MLC, a espécie Liothrips sp. não apresenta um complexo luminal de membranas evidente, mas apenas algumas membranas curtas e raras associadas aos ápices das microvilosidades. Além disso, pequenas trabéculas são também observadas ao longo das microvilosidades dos enterócitos desta espécie, parecendo conectá-las lateralmente, talvez atuando numa função de reforço desta estrutura. Os resultados obtidos em Thysanoptera não apoiam a existência de um complexo luminal de membranas do tipo MPM como descrito na literatura. Assim, as informações levantadas neste trabalho dão suporte a um novo cenário para a evolução do sistema digestivo dos Hemiptera e Thysanoptera, no qual o ancestral comum não apresentaria uma organização do complexo luminal de membranas do tipo MPM, como correntemente descrito na literatura, mas sim do tipo MLC, sendo que o padrão MPM teria surgido nos Hemiptera apenas no grupo dos Heteroptera. A detecção de quitina no complexo luminal do intestino médio de D. maidis e M. fimbriolata por microscopia de fluorescência, utilizando-se um conjugado de WGA-fluoresceína, é um resultado surpreendente e não esperado uma vez ser a quitina, reconhecidamente, um componente importante da membrana peritrófica e não, a priori, de um complexo membranoso de natureza lipoproteica. Por outro lado, a não detecção de quitina em uma espécie de Heteroptera (Dysdercus peruvianis), que possui um complexo luminal de tipo MPM, usada como controle, mostra que a natureza do complexo luminal de membranas nos Condylognatha é muito mais complicada e elaborada do que se pensava inicialmente / This work presents a comprehensive study of the morphology of the digestive system of species of the orders Hemiptera and Thysanoptera, in an evolutionary approach. The main focus of the study is the analysis of the organization of the luminal complex of membranes in the midgut of these species whose presence constitutes one of the most peculiar characteristics found in the insects of the two orders. The species of the orders Hemiptera and Thysanoptera comprise the so-called group of Condylognatha, formed by insects showing variable feeding habits, but mostly sap-sucking ones. The vast majority of insects presents, in their midgut, a chitin-proteic luminal structure called peritrophic membrane which compartmentalizes the digestive process, among other functions. However, this structure is absent in the members of the group Condylognatha, which shows, instead, a very elaborated membranous complex associated to the microvilli of the enterocytes called luminal membrane complex. There are basically three types of luminal membrane complexes described in the literature: the perimicrovilar membranes (PMM), the modified perimicrovilar membranes (PMMm) and the flame-like membranes (FLM). The first descriptions of this complex, of the PMM type, were made in hemipteran insects of the suborder Heteroptera, but there are also some descriptions of PMM in species of the order Thysanoptera. These observations lead to the suggestion of an evolutionary origin of this type of complex from a common ancestral of Condylognatha as an adaptation to a sap-sucking habit. Further studies show the occurrence of the other types of luminal complex in members of the other hemipteran suborders - PMMm in Sternorrhyncha and, more recently, FLM in Auchenorrhyncha - which suggests that this luminal structure is much more diverse than previously expected. In this context, the main focus of this work was to perform a comparative morphofunctional study of the digestive system of species belonging to the group Condylognatha in order to detect and describe the different types of luminal membrane complex found in these insects. To achieve this goal, anatomical, histological and ultrastructural analysis were performed on the digestive system of selected species, using transmission and scanning electron microscopy, along with fluorescence confocal microscopy techniques. Three hemipteran species, belonging to the suborder Auchenorrhyncha, were studied: Dalbulus maidis (Cicadellidae) and Mahanarva fimbriolata (Cercopidae) of the infraorder Cicadormorpha, and Peregrinus maidis (Delphacidae), of the infraorder Fulgonomorpha. Three other species of the order Thysanoptera were also explored: Frankliniella schultzei (Thripidae), Franklinothrips vespiformes (Aeolothripidae) and Liothrips sp. (Phlaeothripinae), where the first two belong to the suborder Terebrantia and the last one to the suborder Tubulifera. The results presented in this work show that the species M. fimbriolata and D. maidis have a luminal membrane complex very similar to the FLM type. In contrast, the species P. maidis presented a very different organization when compared to the known species of the suborder Auchenorrhyncha, which should be considered to be a modification of the FLM model. In this case, a membranous electron-dense layer was detected, which apparently coats the entire membrane complex. Important differences were observed in the structure of the luminal complex among the analyzed thysanopteran species. In the midgut of F. schultzei and F. vespiformes there is a membrane complex similar to the FLM type. However, the species Liothrips sp. does not seem to present any type of membranous complex, displaying only a few short membranes associated to the microvilli. In addition to that, small structures, similar to trabeculae, can be observed along the microvilli of the enterocytes of this species, apparently connecting them laterally, reinforcing this structure. Thus, the results obtained in Thysanoptera do not support the existence of a PMM type of complex in this order, as described in the literature. Therefore, the data collected in this work present a new scenario to the evolution of the digestive system of Hemiptera and Thysanoptera, where the common ancestral would not display a membranous complex of the type PMM, but a FLM complex, with the PMM arising only in the Heteroptera group of Hemiptera. The detection of chitin in the luminal complex of D. maidis and M. fimbriolata by fluorescence microscopy, using a WGA-fluorescein conjugate, is an unexpected result since chitin is an important component of the peritrophic membrane and not, a priori, of a lipoproteic membranous complex. On the other hand, the negative detection of chitin in a heteropteran species (Dysdercus peruvianis), which has a PMM luminal complex and was used as control, indicate that the nature of the luminal membrane complex in the Condylognatha group is far more complicated and elaborate than previously thought

Orientador: Wilson Badiali Crocomo / Banca: Carlos Gilberto Raetano / Banca: Adriana Mascarette Labinas / Banca: Ronaldo Pavarini / Banca: Paulo Sérgio Machado Botelho / Resumo: Com o objetivo de identificar as possíveis espécies de tripes associadas à cultura do milho, a espécie predominante, a proporção de adultos e ninfas, a época de ocor-rência, o período crítico de ataque e a influência do sistema de plantio e das condições climáti-cas sobre a população de tripes e métodos de amostragem, foram conduzidos ensaios na Fa-zenda Experimental de Iguatemi, localizada no Município de Maringá, PR, no período de ou-tubro de 2001 a fevereiro de 2004. As avaliações foram realizadas por meio da coleta de tri-pes com armadilhas adesivas azuis e coletando-se plantas de milho, cortadas rente ao solo, colocadas em sacos plásticos e levadas ao laboratório, onde foram lavadas em álcool 70%, para extração dos tripes. A determinação dos danos provocados pelo tripes foi estudada em cinco experimentos inteiramente casualizados, correlacionando diferentes níveis populacionais de tripes e produtividade. Foi empregado o inseticida thiamethoxan, em tratamento de semen-tes, e pulverizações com metamidofós, em diferentes estágios de desenvolvimento das plantas, para obter parcelas com diferentes níveis de incidência de tripes em períodos pré-determinados. Foram identificadas oito espécies de tripes associadas à cultura do milho, na região, sendo Frankliniella williamsi Hood, 1915, a mais freqüente (99,43%). Verificou-se que a incidência de tripes na cultura de milho em solo coberto com aveia dessecada foi menor do que em solo nu, ou coberto por aveia tombada ou incorporada, sendo que imediatamente após a emergência das plantas a população de tripes era composta quase que exclusivamente por adultos imigrantes. A população de formas jovens começou a aumentar a partir dos 14 dias após a emergência das plantas, indicando a capacidade reprodutiva do tripes na cultura do milho. Foi verificada correlação negativa entre... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: Aiming to identify the possible species of thrips associated to the corn crop, the predominant species, the adult/nymph rate, occurrence time, critical period of attack, influence of the sowing system and climatic conditions on the population of thrips and sampling methods, essays were carried out at the Experimental Farm of Iguatemi, in Maringá, Paraná State, Brazil, from October 2001 to February 2004. The evaluations consisted in collecting thrips with blue adhesive traps and collecting corn plants cuted at soil level, placed into plastic bags and took to the laboratory, where they were washed in alcohol 70%, for the extraction of thrips. The determination of the damages caused by thrips was studied in five experiments, totally randomized, correlating different population levels of thrips and productivity. The insecticide thiamethoxan was applied in seed treatment and methamidophos, in sprayings in different stages of plant development to obtain areas with different levels of incidence of thrips in periods previously established. Eight species of thrips associated to corn crop were identified in the area, being Frankliniella williamsi Hood, 1915, the most frequent (99.43%). It was verified that the incidence of corn thrips in soil covered with dried oats was smaller than in nude soil or in soils covered by cuted or incorporated oat, considering that, immediately after the plants emergence, the population of thrips was composed almost exclusively by emigrant adults. The young population began to increase from 14 days after plant emergence, on indicating thrips reproductivity capacity in corn crops. Negative correlation was verified between the rainfall index and the number of thrips collected in blue traps, but it was not observed any correlation among the number of thrips by corn plant and the number of thrips collected in those traps. It was verified that more than 30 thrips... (Complete abstract, click electronic address below). / Doutor

Doctor of Philosophy / Department of Plant Pathology / Dorith Rotenberg / Frankliniella occidentalis, the western flower thrips, transmits the plant-pathogenic virus, Tomato spotted wilt virus (TSWV), through a circulative-propagative transmission strategy. The virus infects and replicates in the insect, traversing membrane barriers as it moves from the midgut to the salivary glands for subsequent inoculation of a plant host. Based on well-characterized virus-vector systems, many molecular interactions occur as the virus completes an infection cycle in the vector, and knowledge of transcriptome-wide response of thrips to TSWV has been limited. My research goals were to gain insight into i) the molecular responses that occur in thrips vectors of orthotospoviruses, ii) the role of antiviral defense in viruliferous thrips, and iii) plant transgenic-based strategies for studying thrips gene function and crop-pest control. To this end, my specific research objectives were to: 1) generate, assemble, and annotate a RNA-Seq-derived transcriptome for F. occidentalis using the thrips genome, and to quantify global gene expression in response to TSWV activity in larval, pre-pupal, and adult developmental stages, 2) conduct a time-course experiment to determine the effect(s) of challenging TSWV-exposed and non-exposed thrips with dsRNAs of F. occidentalis Dcr-2 or AGO2 by hemocoel injection, and 3) construct transgenic plants expressing a thrips-gene specific dsRNA hairpin to target a vital gene. My research has catalogued insect response to TSWV activity in thrips during development and provides candidate sequences for functional analysis of genes involved in insect development and defense. Successful silencing of the antiviral RNAi pathway in thrips revealed increased mortality and decreased offspring production in both virus-exposed and non-exposed insects. Arabidopsis plants were developed to express dsRNA of vacuolar ATP synthase (V-ATPase) and preliminary feeding bioassays to explore the effect of these transgenics on thrips fitness indicate a need for further description of thrips dsRNA uptake. In total, my research contributes new basic knowledge underpinning the complex and dynamic relationship between thrips vectors and the plant viruses they transmit.

The order Thysanoptera (Insecta: Paraneoptera), commonly known as thrips, includes organisms that exhibit a wide range of social and feeding behaviors that are of particular interest in evolutionary studies. These studies within thrips have been inhibited by the lack of knowledge of thrips relationships. The recognized classification scheme strives to reflect evolutionary relationships and is based upon morphology. Molecular data is next as morphology alone is not enough to resolve relationships. Few molecular studies have been conducted and all were limited in their taxon sampling and genetic sampling. To provide a foundation of future evolutionary studies, the objectives of this study are to (1) test the monophyly of the suborders Terebrantia and Tubulifera, (2) test the monophyly of the families and decipher their relationships, and (3) test the monophyly of the recognized subfamilies. Phylogenies were reconstructed based upon 5299 bp, from five genetic loci: 18S ribosomal DNA, 28S ribosomal DNA, Histone 3 (H3), Tubulin-alpha (TubA) and cytochrome oxidase c subunit I (COI). 99 thrips species from seven of the nine families, all six subfamilies and 70 genera were sequenced. Maximum Parsimony (MP), Maximum Likelihood (ML) and Bayesian analysis all strongly support a monophyletic Tubulifera and Terebrantia. Phlaeothripidae, Aeolothripidae, Melanthripidae and Thripidae are all monophyletic families. The relationship between Aeolothripidae and Merothripidae to the rest of Terebrantia is equivocal. Morphological and molecular data suggest Aeolothripidae or Merothripidae could be the basal lineage of Terebrantia. Four of the six subfamilies are recovered as monophyletic. The two largest subfamilies, Phlaeothripinae and Thripinae, are paraphyletic and require further study to understand relationships within them.

A melancia [Citrullus lanatus (Thunb.) Matsum & Nakai] é originária da África Central, e bastante cultivada por todo o mundo. No ano de 2012, a produção mundial dessa fruta foi 105.372.341 milhões de toneladas, enquanto que o Brasil produziu 2.079.547 milhões toneladas. A cultura da melancia é de suma importância econômica para o estado do Tocantins, com rendimentos no ano de 2013 de 98,5 milhões de reais. A melancia é susceptível à ação de patógenos, sendo as doenças virais de maior relevância. Os vírus do gênero Tospovirus, transmitidos exclusivamente por tripes vetores em diversas culturas, têm causados prejuízos de bilhões de dólares em custos de controle. Os tripes são encontrados em todas as regiões do Brasil, com altas infestações em cultivos de melancia, podendo causar danos diretos e/ou indiretos. Neste trabalho foram coletados espécimes de tripes nos municípios produtores de melancia do estado do Tocantins: Gurupi, Formoso do Araguaia, Lagoa da Confusão e Porto Nacional. A identificação dos caracteres morfológicos dos tripes foi realizada utilizando chave taxonômica apropriada com alterações para identificação das espécies. Parte dos insetos coletados foi realizada a extração de RNA total. Posteriormente, foi sequenciado o extraído com tecnologia de sequenciamento de nova geração (NGS). Foram identificadas três espécies de tripes nos quatro municípios produtores, F. schultzei, F. tritici e F. insularis, com predominância de infestação da espécie F. schultzei. Sendo esta a única entre as identificadas, que é considerada vetor de Tospovirus. Foi identificado nas amostras de tripes, o vírus Groundnut ringspot virus (GRSV), o qual é eficientemente transmitido por F. schultzei. Entre as espécies de tripes identificadas, F. tritici e F. insularis, são registradas pela primeira vez em cultivos comerciais de melancia no Brasil. F. schultzei, é a única com relatos de danos diretos e indiretos causados em plantas de melancia, podendo ser considerada praga potencial à cultura, devido o alto nível populacional encontrado e por dificuldades no controle do tripes. / The Watermelon [Citrullus lanatus (Thunb.) Matsum & Nakai] is originally from Central Africa, and cultivated worldwide. In 2012, the world production of this fruit was 105.372.341 million tons, while Brazil produced 2.079.547 million tons. The watermelon cropping is of paramount economic importance to the state of Tocantins, with revenues of 98.5 million, in 2013. Watermelon is susceptible to the action of microorganisms, and viral diseases presents most relevance. The Tospovirus genus, transmitted exclusively by thrips vectors in diverse crops, have caused losses of billions of dollars in cost control. Thrips are found in all regions of Brazil, with high infestations in watermelon crops, and may cause direct and/or indirect damages. In this work, it was collected thrips specimens from watermelon producers of municipalities in the state of Tocantins: Gurupi, Formoso do Araguaia, Lagoa da Confusão and Porto Nacional. The thrips identification of morphological characters was performed using appropriate taxonomic key with changes to species identification. In part of the collected insects, the total RNA extraction was performed. The extracted was subsequently sequenced with next-generation sequencing technology (NGS). Three species of thrips were identified in the four producing municipalities, F. schultzei, F. tritici, and F. insularis, with predominance of F. schultzei. Among the identified species, only F. schultzei is considered a vector of Tospovirus. In thrips samples it was identified the virus Groundnut ringspot virus (GRSV), which is efficiently transmitted by F. schultzei. Among the species of thrips identified, F. tritici and F. insularis, are registered for the first time in watermelon commercial crops in Brazil. F. schultzei is the only one with reports of direct and indirect damage to watermelon plants and may be considered as a potential plague due the high population level found and difficulties in controlling it.