Orthotospovirus iridimaculaflavi (iris yellow spot virus): An emerging threat to onion cultivation and its transmission by Thrips tabaci in India.

The yellow spot disease caused by the virus species Orthotospovirus iridimaculaflavi (Iris yellow spot virus-IYSV), belonging to the genus Orthotospovirus, the family Tospoviridae, order Bunyavirales and transmitted by Thrips tabaci Lindeman. At present, emerging as a major threat in onion (Allium cepa) in Tamil Nadu, India. The yellow spot disease incidence was found to be 53-73 % in six districts out of eight major onion-growing districts surveyed in Tamil Nadu during 2021-2023. Among the onion cultivars surveyed, the cultivar CO 5 was the most susceptible to IYSV. The population of thrips was nearly 5-9/plant during vegetative and flowering stages. The thrips infestation was 34-60 %. The tospovirus involved was confirmed as IYSV through DAS-ELISA, followed by molecular confirmation through RT-PCR using the nucleocapsid (N) gene. The predominant thrips species present in onion crops throughout the growing seasons was confirmed as Thrips tabaci based on the nucleotide sequence of the MtCOI gene. The mechanical inoculation of IYSV in different hosts viz., Vigna unguiculata, Gomphrena globosa, Chenopodium amaranticolor, Chenopodium quinoa and Nicotiana benthamiana resulted in chlorotic and necrotic lesion symptoms. The electron microscopic studies with partially purified sap from onion lesions revealed the presence of spherical to pleomorphic particles measuring 100-230 nm diameter. The transmission of IYSV was successful with viruliferous adult Thrips tabaci in cowpea (Cv. CO7), which matured from 1st instar larva fed on infected cowpea leaves (24 h AAP). Small brown necrotic symptoms were produced on inoculated plants after an interval of four weeks. The settling preference of non-viruliferous and viruliferous T. tabaci towards healthy and infected onion leaves resulted in the increased preference of non-viruliferous thrips towards infected (onion-61.33 % and viruliferous thrips towards healthy onion leaves (75.33 %). The study isolates shared 99-100 % identity at a nucleotide and amino acid level with Indian isolates of IYSV in the N gene. The multiple alignment of the amino acid sequence of the N gene of IYSV isolates collected from different locations and IYSV isolates from the database revealed amino acid substitution in the isolate ITPR4. All the IYSV isolates from India exhibited characteristic amino acid substitution of serine at the 6th position in the place of threonine in the isolates from Australia, Japan and USA. The phylogenetic analysis revealed the monophyletic origin of the IYSV isolates in India.

Physiological responses and transcriptome analysis of Hemerocallis citrina Baroni exposed to Thrips palmi feeding stress.

Thrips are serious pests of Hemerocallis citrina Baroni (daylily), affecting crop yield and quality. To defend against pests, daylily has evolved a set of sophisticated defense mechanisms. In the present study, induction of systemic resistance in Hemerocallis citrina 'Datong Huanghua' by Thrips palmi feeding was investigated at both biochemical and molecular levels. The soluble sugar content of daylily leaves was significantly lower than that in control check (CK) at all time points of feeding by T. palmi, whereas the amino acid and free fatty acid contents started to be significantly lower than those in CK after 7 days. Secondary metabolites such as tannins, flavonoids, and total phenols, which are harmful to the growth and reproduction of T. palmi, were increased significantly. The activities of defense enzymes such as peroxidase (POD), phenylalanine ammonia lyase (PAL), and polyphenol oxidase (PPO) were significantly increased, and the degree of damage to plants was reduced. The significant increase in protease inhibitor (PI) activity may lead to disrupted digestion and slower growth in T. palmi. Using RNA sequencing, 1,894 differentially expressed genes (DEGs) were identified between control and treatment groups at five timepoints. DEGs were mainly enriched in secondary metabolite synthesis, jasmonic acid (JA), salicylic acid (SA), and other defense hormone signal transduction pathways, defense enzyme synthesis, MAPK signaling, cell wall thickening, carbohydrate metabolism, photosynthesis, and other insect resistance pathways. Subsequently, 698 DEGs were predicted to be transcription factors, including bHLH and WRKY members related to biotic stress. WGCNA identified 18 hub genes in four key modules (Purple, Midnight blue, Blue, and Red) including MYB-like DNA-binding domain (TRINITY_DN2391_c0_g1, TRINITY_DN3285_c0_g1), zinc-finger of the FCS-type, C2-C2 (TRINITY_DN21050_c0_g2), and NPR1 (TRINITY_DN13045_c0_g1, TRINITY_DN855_c0_g2). The results indicate that biosynthesis of secondary metabolites, phenylalanine metabolism, PIs, and defense hormones pathways are involved in the induced resistance to T. palmi in daylily.

Risk assessment of Retithrips syriacus for the EU.

Following a request from the European Commission, the EFSA Panel on Plant Health performed a quantitative risk assessment for the EU of Retithrips syriacus (Mayet) (Thysanoptera: Thripidae), a polyphagous thrips, regarded as a tropical/subtropical pest occurring in several countries of Africa, South America, Asia and in the EU in Cyprus. The current risk assessment focused on potential pathways for entry, the climatic conditions allowing establishment, the expected spread capacity and the impact considering a time horizon of 10 years (2023-2032). The Panel identified the import of cut roses, persimmons, table grapes, as well as plants for planting of the genera Acalypha and Terminalia from third countries and those of Persea americana (avocado) from Israel as the most relevant entry pathways to consider. Over the next 10 years, an annual median estimate of 95 (90% Certainty Range, CR, ranging from 13 to 1832) potential R. syriacus founder populations per year are expected to successfully transfer to a suitable host in the EU NUTS2 regions where the climatic conditions are predicted as suitable for establishment; this value drops to a median of 4.6 founder populations per year (90% CR: 1 every 1.9 years - 85.6 per year) after considering the actual probability of establishment of a potential founder population. The estimated number of founder population per year is mostly driven by the import of cut roses and plants for planting. If such founder populations were to establish, R. syriacus is estimated to spread at a median rate of 0.05 km/year (90% CR 0.02-2.30 km/year) after a median lag phase of 1.1 years (90% CR 0.3-3.3 years). The overall impact on yield (expressed as % of the total agricultural production) directly attributable to R. syriacus when considering: (i) the main R. syriacus hosts in the EU, (ii) the areas of the EU where establishment is possible, (iii) the current agricultural practices and (iv) the evidence of impact from the countries where the pest is established for a long time, was estimated at 0.065% as the median value of the uncertainty distribution (90% CR 0.001%-0.571%). Options for risk reduction are discussed, but the effectiveness was not quantified.

Revisiting a pollen-transmitted ilarvirus previously associated with angular mosaic of grapevine.

We report the characterization of a novel tri-segmented RNA virus infecting Mercurialis annua, a common crop weed and model species in plant science. The virus, named "Mercurialis latent virus" (MeLaV) was first identified in a mixed infection with the recently described Mercurialis orthotospovirus 1 (MerV1) on symptomatic plants grown in glasshouses in Lausanne (Switzerland). Both viruses were found to be transmitted by Thrips tabaci, which presumably help the inoculation of infected pollen in the case of MeLaV. Complete genome sequencing of the latter revealed a typical ilarviral architecture and close phylogenetic relationship with members of the Ilarvirus subgroup 1. Surprisingly, a short portion of MeLaV replicase was found to be identical to the partial sequence of grapevine angular mosaic virus (GAMV) reported in Greece in the early 1990s. However, we have compiled data that challenge the involvement of GAMV in angular mosaic of grapevine, and we propose alternative causal agents for this disorder. In parallel, three highly-conserved MeLaV isolates were identified in symptomatic leaf samples in The Netherlands, including a herbarium sample collected in 1991. The virus was also traced in diverse RNA sequencing datasets from 2013 to 2020, corresponding to transcriptomic analyses of M. annua and other plant species from five European countries, as well as metaviromics analyses of bees in Belgium. Additional hosts are thus expected for MeLaV, yet we argue that infected pollen grains have likely contaminated several sequencing datasets and may have caused the initial characterization of MeLaV as GAMV.

Nitrogen Deficiency Enhances Eggplant Defense against Western Flower Thrips via the Induction of the Jasmonate Pathway.

Plant nutrition is connected to defense against insect herbivores, but the exact mechanism underlying the effect of the nitrogen (N) supply on the anti-herbivore capacity of eggplants (Solanum melongena) has not been studied in detail. Therefore, we examined the impact of low (LN, 0.5 mM) and high (HN, 5 mM) nitrate levels on eggplant resistance against the western flower thrips Frankliniella occidentalis (WFT), a major destructive eggplant pest. Our results showed that LN plants displayed enhanced defense responses to WFT compared to HN plants. This included increased transcript levels of key genes in the jasmonic acid (JA) pathway, the accumulation of JA-amido conjugates (jasmonoyl-isoleucine, jasmonoyl-phenylalanine, and jasmonoyl-valine), JA precursor (12-oxophytodienoic acid), and methyl jasmonate, higher transcript levels of defense marker genes (MPK3, MPK7, and WRKY53), and increased activities of polyphenol oxidase and peroxidase upon a WFT attack. Our findings suggest that N deficiency can prime JA-mediated defense responses in eggplants, resulting in increased anti-herbivore resistance.

Molecular characterization and incidence of new tospovirus: Soybean Vein Necrosis Virus (SVNV) in Egypt / Caracterização molecular e incidência de novo tospovírus: Vírus da Necrose da Veia da Soja (SVNV) no Egito

Abstract Field survey study was conducted season (2017). Soybeans and weeds were weekly sampled randomly. Thrips adults were identified and counted. Detection of the virus isolate and the natural incidence was determined using; Mechanical transmission, host range, DAS-ELISA, RT-PCR. The natural incidence thrips individuals was detected depending on the SVNV% in thrips individuals and weeds hosts. Ten thrips species were associated with soybean plants in the field. The most abundant species was T. tabaci, average 256.5 average no.of individuals, followed by F. occidentalis (142.5 average no. of individuals), then N. variabilis (86.6/ average no. of individuals). Fourteen thrips species occurred on 5 legumes field crops and 41 weed plant species within soybean field. The highest average number 40.6.of individuals were recorded on Ammi majus. While the lowest one 3.3 average no. of individuals were on Urtica urens. Only 21diagnostic plant species were susceptible to infection with SVNV. G. max and Vigna radiate, were the highest percentage of infection 80% followed by V. unguilata & N. benthamiana, 75%. Egyptian isolate of Soybean vein necrosis virus (SVNV) in this study showed a high degree of similarity and it is closely related to TSWV from Egypt (DQ479968) and TCSV from USA (KY820965) with nucleotide sequence identity of 78%. Four thrips species transmitted SVNV (F. fusca 4.0%, F. schultzei 4.3%, F. tritici 3.3% and N. variabilis 68.0% transmission). Both C. phaseoli and M. sjostedti can acquire the virus but unable to transmit it. The following species; T. tabaci, F. occidentalis, S. dorsallis and T. palmi cannot acquire or transmit SVNV. The incidence of SVNV in the field started by the end of July then increased gradualy from 12.7 to 71.3% by the end of the season. In conclusion, few thrips individuals invaded soybean crops are enough to transmit high rate of SVNV within the crop. Furthermore, several vector species are also abundant on weeds, which are the major sources of soybean viruses transmitted to the crops. This information might be important for control and reduce the incidence of SVNV infection.

Resumo O estudo de pesquisa de campo foi realizado na temporada (2017). A soja e as ervas daninhas foram amostradas semanalmente de forma aleatória. Tripes adultos foram identificados e contados. A detecção do vírus isolado e a incidência natural foram determinadas usando transmissão mecânica, gama de hospedeiros, DAS-ELISA, RT-PCR. A incidência natural de tripes em indivíduos foi detectada dependendo da % de SVNV em tripes e hospedeiros infestantes. Dez espécies de tripes foram associadas a plantas de soja no campo. A espécie mais abundante foi T. tabaci, com média de 256,5 número médio de indivíduos, seguida por F. occidentalis (142,5) e N. variabilis (86,6 / número médio de indivíduos). Catorze espécies de tripes ocorreram em 5 culturas de leguminosas e 41 espécies de plantas daninhas dentro de campos de soja. O maior número médio de 40,6 indivíduos foi registrado em Ammi majus. Enquanto o mais baixo, 3,3 número médio de indivíduos, foi no Urtica urens. Apenas 21 espécies de plantas diagnosticadas foram suscetíveis à infecção com SVNV. G. max e Vigna radiate foram os maiores percentuais de infecção, 80%, seguidos por V. unguilata e N. benthamiana, 75%. O isolado egípcio neste estudo mostrou um alto grau de similaridade e está intimamente relacionado ao TSWV do Egito (DQ479968) e ao TCSV dos EUA (KY820965), com identidade de sequência de nucleotídeos de 78%. Quatro espécies de tripes transmitiram SVNV (F. fusca 4,0%, F. schultzei 4,3%, F. tritici 3,3% e N. variabilis 68,0% de transmissão). Tanto C. phaseoli quanto M. sjostedti podem adquirir o vírus, mas não podem transmiti-lo. As seguintes espécies, T. tabaci, F. occidentalis, S. dorsallis e T. palmi não podem adquirir ou transmitir SVNV. A incidência de SVNV no campo, iniciada no final de julho, aumentou gradativamente de 12,7 para 71,3% no final da temporada. Em conclusão, poucos indivíduos de tripes invadiram a cultura da soja e são suficientes para transmitir alta taxa de SVNV dentro da cultura. Além disso, várias espécies de vetores também abundam em ervas daninhas, que são as principais fontes dos vírus da soja transmitidos às lavouras. Essas informações podem ser importantes para controlar e reduzir a incidência de infecção por SVNV.

Molecular characterization and incidence of new tospovirus: Soybean Vein Necrosis Virus (SVNV) in Egypt

Abstract Field survey study was conducted season (2017). Soybeans and weeds were weekly sampled randomly. Thrips adults were identified and counted. Detection of the virus isolate and the natural incidence was determined using; Mechanical transmission, host range, DAS-ELISA, RT-PCR. The natural incidence thrips individuals was detected depending on the SVNV% in thrips individuals and weeds hosts. Ten thrips species were associated with soybean plants in the field. The most abundant species was T. tabaci, average 256.5 average no.of individuals, followed by F. occidentalis (142.5 average no. of individuals), then N. variabilis (86.6/ average no. of individuals). Fourteen thrips species occurred on 5 legumes field crops and 41 weed plant species within soybean field. The highest average number 40.6.of individuals were recorded on Ammi majus. While the lowest one 3.3 average no. of individuals were on Urtica urens. Only 21diagnostic plant species were susceptible to infection with SVNV. G. max and Vigna radiate, were the highest percentage of infection 80% followed by V. unguilata & N. benthamiana, 75%. Egyptian isolate of Soybean vein necrosis virus (SVNV) in this study showed a high degree of similarity and it is closely related to TSWV from Egypt (DQ479968) and TCSV from USA (KY820965) with nucleotide sequence identity of 78%. Four thrips species transmitted SVNV (F. fusca 4.0%, F. schultzei 4.3%, F. tritici 3.3% and N. variabilis 68.0% transmission). Both C. phaseoli and M. sjostedti can acquire the virus but unable to transmit it. The following species; T. tabaci, F. occidentalis, S. dorsallis and T. palmi cannot acquire or transmit SVNV. The incidence of SVNV in the field started by the end of July then increased gradualy from 12.7 to 71.3% by the end of the season. In conclusion, few thrips individuals invaded soybean crops are enough to transmit high rate of SVNV within the crop. Furthermore, several vector species are also abundant on weeds, which are the major sources of soybean viruses transmitted to the crops. This information might be important for control and reduce the incidence of SVNV infection.

Resumo O estudo de pesquisa de campo foi realizado na temporada (2017). A soja e as ervas daninhas foram amostradas semanalmente de forma aleatória. Tripes adultos foram identificados e contados. A detecção do vírus isolado e a incidência natural foram determinadas usando transmissão mecânica, gama de hospedeiros, DAS-ELISA, RT-PCR. A incidência natural de tripes em indivíduos foi detectada dependendo da % de SVNV em tripes e hospedeiros infestantes. Dez espécies de tripes foram associadas a plantas de soja no campo. A espécie mais abundante foi T. tabaci, com média de 256,5 número médio de indivíduos, seguida por F. occidentalis (142,5) e N. variabilis (86,6 / número médio de indivíduos). Catorze espécies de tripes ocorreram em 5 culturas de leguminosas e 41 espécies de plantas daninhas dentro de campos de soja. O maior número médio de 40,6 indivíduos foi registrado em Ammi majus. Enquanto o mais baixo, 3,3 número médio de indivíduos, foi no Urtica urens. Apenas 21 espécies de plantas diagnosticadas foram suscetíveis à infecção com SVNV. G. max e Vigna radiate foram os maiores percentuais de infecção, 80%, seguidos por V. unguilata e N. benthamiana, 75%. O isolado egípcio neste estudo mostrou um alto grau de similaridade e está intimamente relacionado ao TSWV do Egito (DQ479968) e ao TCSV dos EUA (KY820965), com identidade de sequência de nucleotídeos de 78%. Quatro espécies de tripes transmitiram SVNV (F. fusca 4,0%, F. schultzei 4,3%, F. tritici 3,3% e N. variabilis 68,0% de transmissão). Tanto C. phaseoli quanto M. sjostedti podem adquirir o vírus, mas não podem transmiti-lo. As seguintes espécies, T. tabaci, F. occidentalis, S. dorsallis e T. palmi não podem adquirir ou transmitir SVNV. A incidência de SVNV no campo, iniciada no final de julho, aumentou gradativamente de 12,7 para 71,3% no final da temporada. Em conclusão, poucos indivíduos de tripes invadiram a cultura da soja e são suficientes para transmitir alta taxa de SVNV dentro da cultura. Além disso, várias espécies de vetores também abundam em ervas daninhas, que são as principais fontes dos vírus da soja transmitidos às lavouras. Essas informações podem ser importantes para controlar e reduzir a incidência de infecção por SVNV.

Rearing Frankliniella zucchini Nakahara & Monteiro (Thysanoptera: Thripidae) on zucchini (Cucurbita pepo L. 'Caserta') fruits

Abstract Frankliniella zucchini transmits zucchini lethal chlorosis virus, causal agent of lethal chlorosis of zucchini squash. The characteristics of relationship between this virus with its vector have not been studied, one of the reasons being the lack of a method for rearing the thrips for laboratory studies. This work proposes a system for the rearing of F. zucchini on fresh virus free zucchini 'Caserta' fruits, offering a practical and efficient alternative for the supply of a large number of insects for later study of virus/vector relationship. In addition, to aid in the identification of this species of thrips, the immature and adult forms obtained from the colony were described.

Identification and pest status of Holopothrips fulvus (Thysanoptera: Phlaeothripidae) on dwarf-cashew crops in northeastern Brazil

Abstract Cashew, Anacardium occidentale L. (Anacardiaceae), is one of the most important sources of agricultural income in northeastern Brazil, but many of the arthropods associated with the crop have yet to be identified. We describe here for the first time the damage caused by Holopothrips fulvus (Morgan) (Thysanoptera: Phlaeothripidae) to dwarf-cashew trees cultivated in the municipality of Pacajús, Ceará, Brazil. Leaf tissue injuries were caused by the sucking mouthparts of the insect and were characterized by dark necrotic spots on the epidermis that resulted in yellowing, wilting and, ultimately, abscission of the leaves. H. fulvus also fed on developing kernels and pseudofruits producing injuries that manifested in the form of chlorotic specks. Additional information is given on the pest status and important aspects of the morphology of the insect, including sexual dimorphism, redescription of the adults and description of the second instar larvae.

Altas diluições de Solanum lycopersicum e Camellia sinensis no manejo fitossanitário e rendimento de cebola em sistema orgânico / High dilutions of Solanum lycopersicum and Camellia sinensis on the phytosanitary management and yield of onion under organic system

A utilização frequente de agrotóxicos no manejo fitossanitário da cultura da cebola tem causado impactos no meio ambiente e possíveis resíduos tóxicos nos bulbos para consumo humano. Substâncias em altas diluições têm sido estudadas no manejo fitossanitário da culturada cebola para viabilizar sistemas ecologicamente viáveis. O objetivo deste estudo foi avaliar o efeito de altas diluições a partir da matéria prima de mudas de tomate, Solanum lycopersicumL., cv. Perinha e de folhas de chá-verde, Camellia sinensis (L.) Kuntze, sobre a incidência e danos de tripes, Thrips tabaci, severidade do míldio, Peronospora destructor, e no rendimento de cebola em sistema de produção orgânico. O estudo foi conduzido a campo, nos anos de2014 e 2015, na Epagri/Estação Experimental de Ituporanga, Santa Catarina, Brasil. Os experimentos foram realizados separadamente para altas diluições de plantas de tomate e de folhas desidratadas de chá-verde. Os tratamentos foram altas diluições em pulverizações foliares a 6, 12 e 30cH e testemunha sem aplicação. O delineamento experimental foi casualizado em blocos, com 4 repetições. A incidência de tripes, severidade do míldio e rendimento de cebola não foram influenciados pelos tratamentos. Altas diluições de chá-verdenas diluições 6 e 30cH reduziram os danos de tripes.

Frequent use of pesticides in onion crop management may have impact on the environment andhuman health. Substances in high dilution have been studied to replace chemicals inecologically viable onion crop systems. The aim of the present study was to evaluate the effectof high dilutions of tomato, Solanum lycopersicum L., cv. Perinha and green tea, Camelliasinensis (L.) Kuntze, on the incidence and damage of thrips, Thrips tabaci, severity of downymildew, Peronospora destructor, and on the onion yield in an organic production system. Thestudy was carried out under field conditions at Epagri/Experimental Station of Ituporanga, Santa Catarina, Brazil, in 2014 and 2015. The experiments were performed separately for highdilutions of tomato and green tea leaves. The treatments consisted in foliar sprays with highdilutions 6, 12 and 30 cH and control without application. The experimental design consisted ofrandomized blocks with 4 replications. The incidence of onion thrips, downy mildew severityand yield were not affected by treatments. Green tea at 6 and 30cH reduced the damage bythrips.

Cymbopogon citratus (Poaceae) essential oil on Frankliniella schultzei (Thysanoptera: Thripidae) and Myzus persicae (Hemiptera: Aphididae) / Óleo essencial de Cymbopogon citratus (Poaceae) Sobre Frankliniella schultzei (Thysanoptera: Thripidae) e Myzus persicae (Hemiptera: Aphididae)

Phytovirus vectors Frankliniella schultzei (Trybom, 1920) (Thysanoptera: Thripidae) and Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) feed on crops of great economic importance brings large economic losses worldwide to cultivated species such as tomato and cotton. F. schultzei transmits Tospovirus, Groundnut ring spot virus (GRSV) and Tomato spotted wilt virus (TSWV) to tomato plants and M. persicae transmits Potato virus Y (PVY), Tomato yellow top virus (ToYTV) and Tomato bottom yellow leaf virus (TBYLV) to tomato crops. Chemical constituents of essential oils have been increasingly studied because they present a wide range of biological activities. The aim of this work was to characterize Cymbopogon citratus essential oil and evaluate its potential insecticide activity against F. schultzei and M. persicae. The essential oil was obtained from fresh leaves by hydrodistillation using a Clevenger apparatus. Its yield (1.04%) was determined relative to the dry mass of the plant. Qualitative analysis was performed by gas chromatography coupled to mass spectrometry and chemical constituent content was determined by gas chromatography with a flame ionization detector. Nine compounds were identified, with geranial (49.98%) and neral (37.78%) being the major components. The insects were sprayed with C. citratus essential oil at different concentrations using a Potter tower. The LC50 values for M. persicae and F. schultzei were 0.28% and 1.49%, respectively. Essential oil from C. citratus is a promising natural alternative for developing pesticides to manage M. persicae.

Os vetores de fitovírus Frankliniella schultzei (Trybom, 1920) (Thysanoptera: Thripidae) e Myzus persicae (Sulzer, 1776) (Hemiptera: Aphididae) se alimentam de culturas de grande importância econômica, trazendo grandes perdas econômicas em todo o mundo para as espécies cultivadas, como tomate e algodão. F. schultzei transmite Tospovirus, Groundnut ring spot virus (GRSV) e Tomato spotted wilt virus (TSWV) em tomateiro and M. persicae transmite Potato virus Y (PVY), Tomato yellow top virus (ToYTV) e Tomato bottom yellow leaf virus (TBYLV) ao tomateiro. Os constituintes químicos dos óleos essenciais têm sido cada vez mais estudados, pois apresentam uma ampla gama de atividades biológicas. O objetivo deste trabalho foi caracterizar o óleo essencial de Cymbopogon citratus e avaliar o seu potencial inseticida sobre F. schultzei e M. persicae. O óleo essencial foi obtido a partir de folhas frescas por hidrodestilação utilizando um aparelho Clevenger. O seu rendimento (1,04%) foi determinado em relação à massa seca da planta. A análise qualitativa foi realizada por cromatografia gasosa acoplada a espectrometria de massa e o teor dos constituintes químicos foi determinado por cromatografia gasosa com detector de ionização de chama. Nove compostos foram identificados, com geranial (49,98%) e neral (37,78%), sendo os componentes principais. Os insetos foram pulverizados com óleo essencial de C. citratus em diferentes concentrações utilizando uma torre de Potter. Os valores de CL50 de M. persicae e F. schultzei foram de 0,28% e 1,49%, respectivamente. Óleo essencial de C. citratus é uma alternativa natural promissor para o desenvolvimento de inseticidas para o manejo de M. persicae.

Qualidade da aplicação de inseticida em amendoim (Arachis hypogaea L), com e sem adjuvantes na calda, sob chuva simulada / Quality of inseticide application on peanut (Arachis hypogaea L), with and without adjuvants in the spraying liquid, under simulated rain

O trabalho objetivou avaliar os perfis de distribuição volumétrica, o diâmetro de gotas, a tensão superficial, o ângulo de contato de gotas e a deposição de calda de pulverização sobre folhas de amendoim (Arachis hypogaea L.) submetidas à chuva artificial, em comparação à deposição sem chuva, usando-se dois modelos de pontas hidráulicas de jatos planos e caldas inseticidas com e sem adição de adjuvantes. Utilizou-se mesa de deposição para análise da distribuição volumétrica, analisador de partículas a laser para avaliar o diâmetro de gotas formadas pelas pontas SF 110015 e XR 110015 e tensiômetro para as análises de tensão e ângulo de contato de gotas. As caldas avaliadas foram: água, lambda-cialotrina, lambda-cialotrina + tributilcitrat + polidimetilsiloxano e lambda-cialotrina + óleo mineral. Os ensaios seguiram um delineamento inteiramente casualizado. Os dados foram submetidos à análise de variância pelo teste F e as comparações das médias pelo teste de Scott-Knott a 5% de probabilidade. Concluiu-se que deve ser considerado um espaçamento máximo na barra de pulverização de 50 e 90 cm entre as pontas, para SF 110015 e XR 110015, respectivamente. O efeito dos adjuvantes no diâmetro de gotas depende da ponta de pulverização e do produto empregado, sendo que a adição dos adjuvantes à calda afetou o risco potencial de deriva; O Diâmetro Mediano Volumétrico (DMV) das gotas produzidas pelas pontas enquadraram-se na classe fina e não foram influenciados pelos adjuvantes. O tributilcitrat + polidimetilsiloxano pode ser indicado para melhorar a cobertura e deposição de gotas no alvo.

The present work aimed to evaluate the volumetric distribution profiles, droplet spectra, surface tension, contact angle of droplet and the spraying liquid deposition over the peanut leaves (Arachis hypogaea L.), under artificial rain, in comparison with deposition without rain, using two hydraulic nozzle models of plain fan and insecticide spraying liquids with and without adjuvants addition. It were used a patternator for volumetric distribution analysis, a laser particles analyzer to evaluate droplet spectra produced by SF 110015 and XR 110015 nozzles and tensiometer for droplet tension and contact angle. The spraying liquids evaluated were: water, lambda-cialotrina, lambda-cialotrina + nitrogen fertilizer and lambda-cialotrina + mineral oil. All experiments followed a completely randomized design. Data were submitted to variance analysis by F test and the means comparisons by Scott-Knott test at 5% of probability. According to the results, it must be considered the maximum spacing in spray boom usage of 50 and 90 cm between the nozzles SF110015 and XR110015, respectively. The adjuvants effects on droplet spectra have shown addicted to the nozzle and the product used, and the adjuvants addition to the spraying liquid affected the potential risk of drift; The Volumetric Median Diameter (VMD) of produced droplets by nozzles filled into thin class and were not influenced by the adjuvants. The nitrogen fertilizer adjuvant may be indicated to promote improvements on coverage and droplet deposition on target.

Thrips species (Insecta: Thysanoptera) associated to Fabaceae of agricultural importance in Cerrado and Amazon-Caatinga ecotone from Brazilian Mid-North

Little is known about the Thysanoptera fauna from Brazilian Mid-North. In spite of being a region with at least three biomes and some ecotones, the studies on this insect order in the region are related to associations to a few cultivated plant species. On Fabaceae, plant family with the second largest number of records of thrips species associated in Brazil and huge economic importance for Mid-North, there are thrips records only on cowpea (Vigna unguiculata (L.) Walp.). Due to the lack of knowledge on the Thysanoptera fauna in such a diverse area and the importance of crops of this family in the region, this research aimed to survey the thrips species associated to Fabaceae of agricultural importance in areas of Cerrado and Amazon-Caatinga ecotone in Brazilian Mid-North, as well as provide basic biological information about damage and hosts. Also, comparison between the Thysanoptera fauna of fabaceous crops in the region and the rest of the Country and a key to species are presented. Thrips were collected on six fabaceous crops in four municipalities in the state of Maranhão and in one municipality in the state of Piauí. Eight thrips species were identified: Caliothrips phaseoli (Pergande, 1895), Frankliniella brevicaulis Hood, 1937, F. gardeniae Moulton, 1948, F. insularis (Franklin, 1908), F. schultzei (Trybom, 1910), F. tritici (Fitch, 1855), Haplothrips gowdeyi (Franklin, 1908) and Salpingothrips minimus Hood, 1935. Two other unidentified species were collected: Plesiothrips sp. and Scolothrips sp. Except for F. schultzei, the thrips species surveyed in Maranhão are first records in the state, and F. gardeniae is first record in the state of Piauí. The first records of thrips on Phaseolus lunatus L. in Brazil were established. Some species known as pests of Fabaceae mostly in southern and southeastern Brazil were not found in Mid-North. Voucher-specimens are deposited at the Entomological Collection of the Department of Entomology and Acarology, Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo (ESALQ/USP).

Pouco se sabe sobre a fauna de Thysanoptera do Meio-Norte do Brasil. A despeito de ser uma região com pelo menos três biomas e alguns ecótonos, os estudos sobre essa ordem de insetos na região são relacionados a associações a poucas espécies vegetais cultivadas. Em Fabaceae, família vegetal com o segundo maior número de registros de espécies de tripes associadas no Brasil e grande importância econômica no Meio-Norte, há registros somente em feijão caupi (Vigna unguiculata (L.) Walp.). Devido à falta de dados sobre a fauna de Thysanoptera nessa área diversa e à importância de culturas dessa família na região, esta pesquisa teve como objetivo conhecer as espécies de tripes associadas a Fabaceae de importância agrícola em áreas de Cerrado e ecótono Amazônia-Caatinga no Meio-Norte do Brasil, bem como disponibilizar informações biológicas básicas sobre danos e hospedeiros. Além disso, comparações entre as faunas de Thysanoptera de fabáceas cultivadas na região e no resto do País e uma chave para as espécies são apresentadas. Os tripes foram coletados em seis espécies de Fabaceae de importância agrícola em quatro municípios do estado do Maranhão e em um município no estado do Piauí. Oito espécies de tripes foram identificadas: Caliothrips phaseoli (Pergande, 1895), Frankliniella brevicaulis Hood, 1937, F. gardeniae Moulton, 1948, F. insularis (Franklin, 1908), F. schultzei (Trybom, 1910), F. tritici (Fitch, 1855), Haplothrips gowdeyi (Franklin, 1908) e Salpingothrips minimus Hood, 1935. Duas outras espécies não identificadas foram coletadas: Plesiothrips sp. e Scolothrips sp. Exceto por F. schultzei, todas as espécies de tripes coletadas no Maranhão são registradas pela primeira vez no estado, e F. gardeniae é registrada pela primeira vez no estado do Piauí. Foram estabelecidos os primeiros registros de tripes em Phaseolus lunatus L. no Brasil. Algumas espécies conhecidas como pragas de Fabaceae no Brasil, principalmente no sul e sudeste, não foram encontradas no Meio-Norte. Os espécimes-testemunha estão depositados na Coleção Entomológica do Departamento de Entomologia e Acarologia da Escola Superior de Agricultura “Luiz de Queiroz”, Universidade de São Paulo (ESALQ / USP).

Occurrence of Enneothrips flavens moulton and Stegasta bosquella (Chambers) and its effects on agronomic traits of wild Arachis accessions / Ocorrência de Enneothrips flavens moulton e Stegasta bosquella (Chambers) e seus efeitos em caracteres agronômicos de acessos de espécies silvestres de arachis

Some wild species of the genus Arachis have demonstrated potential for improvement of peanuts. This work was performed to evaluate the occurrence and symptoms of Enneothrips flavens and Stegasta bosquella and its effects on agronomic traits of wild Arachis accessions. Nine accessions of wild Arachis species and a commercial A. hypogaea variety were studied in a split plot statistical scheme with a completely randomized block design and four replications. The main plots consisted of plants sprayed or not sprayed for insect control, while the subplots comprised the peanut accessions. Accessions GKP10017 (A. cardenasii) and V7639 (A. kuhlmannii) showed the lowest percentages of leaflets with E. flavens and S. bosquella. Accessions V9912, V7639 and V8979 (all three A. kuhlmannii) and V13250 (A. kempff-mercadoi) showed the lowest responses to insecticide application among the various plant traits evaluated. These accessions are of interest for further studies to identify mechanisms of resistance, to be used in breeding programs for resistance to these insects.

Algumas espécies silvestres do gênero Arachis têm demonstrado potencial para melhoramento do amendoim cultivado. Objetivou-se avaliar a ocorrência e os sintomas de Enneothrips flavens e Stegasta bosquella e seus efeitos nos caracteres agronômicos de acessos de Arachis spp. O delineamento estatístico utilizado foi o de blocos ao acaso, em esquema de parcelas subdivididas, sendo a aplicação ou não de inseticidas as parcelas e os acessos (dez materiais) as subparcelas, com quatro repetições. Os acessos GKP10017 (A. cardenasii) e V7639 (A. kuhlmannii) apresentaram as menores percentagens de folíolos com presença de E. flavens e S. bosquella e os acessos V9912, V7639 e V8979 (todos A. kuhlmannii) e V13250 (A. kempff-meradoi) se destacaram por apresentarem baixa resposta em relação à aplicação de inseticidas nos diferentes parâmetros avaliados. Esses acessos são de interesse para estudar os possíveis mecanismos de resistência às pragas e aproveitá-los em programas de melhoramento visando resistência.

Sequential sampling of Aphis gossypii Glover (Hemiptera: Aphididae) and Frankliniella schultzei Trybom (Thysanoptera: Thripidae) on cotton crop

The goal of this research was to use the sequential probability ratio test to establish a sequential sampling plan for Aphis gossypii Glover and Frankliniella schultzei Trybom infesting cotton. Field work was conducted at the agricultural experimental station of the Universidade Federal da Grande Dourados during the 2003/2004 and 2004/2005 agricultural years. Aphid colonies and individual thrips in the sampling area were counted and their numbers were recorded. The spatial distribution pattern of A. gossypii and F. schultzei in the cotton culture was aggregated. Sequential sampling plans were developed for aphids and thrips with type I and type II errors set at 0.1, common Kc = 0.6081 (aphids) and = 0. 9449 (thrips), and safety and management levels of 20 percent (aphids) and 40 percent (thrips) of infested plants. The sampling plans resulted in two decision boundaries for each species, as follows: the upper boundary, indicating when management (population control) is recommended: S1 = 4.6546 + 0.2849n (aphids), and S1 = 3.6514 + 0.1435n (thrips); and the lower boundary, indicating when population control is not necessary: S0 = -4.6546 + 0.2849n (aphids) and S0 = - 3.6514 + 0.1435n (thrips). The highest probability of error when making a decision was 3 percent for aphids and 2 percent for thrips, respectively. The maximum number of samples required to reach a decision was 63 for aphids and 95 for thrips.

Caracterização das injúrias causadas por Frankliniella occidentalis no morangueiro / Injury characterization of Frankliniella occidentalis in strawberry

Frankliniella occidentalis tem sido relatada como uma das principais pragas associadas à cultura do morangueiro. No entanto, os sintomas do ataque do inseto não estão caracterizados e, geralmente, atribui-se ao ataque do inseto a presença de frutos deformados. As injúrias causadas por F. occidentalis foram caracterizadas na cultura do morangueiro infestando-se com adultos botões florais e frutos. Para cada órgão (flores e frutos) e fase de desenvolvimento, foram utilizados 20 insetos, os quais foram mantidos em gaiolas por cinco dias. Também foi avaliado um tratamento em que foram colocados 20 insetos a cada cinco dias, durante todo o ciclo da cultura. Nas flores, foram constatadas injúrias causadas pela alimentação de F. occidentalis nos estames e no receptáculo floral. Em frutos verdes e maduros, foi observado bronzeamento na base dos frutos, sob o cálice, e ao redor dos aquênios. No tratamento no qual os insetos estiveram presentes durante todo o desenvolvimento dos frutos, foram registrados somente 17,6 por cento destes com mais de 40 por cento da superfície com bronzeamento. Não foi encontrada associação entre a infestação por tripes e a deformação de frutos. A alimentação de F. occidentalis na cultura do morangueiro causa injúrias nos estames e no receptáculo floral e bronzeamento na superfície dos frutos verdes e maduros, sem provocar deformações.

Frankliniella occidentalis has been reported as one of the major pests associated with strawberry. However, the symptoms of insect attack are not characterized and their presence are related to deformed fruits. The injury caused by F. occidentalis in strawberries was studied by infesting flowers, unripe and ripe fruits with 20 adult for five days and during all the ripening period inoculating 20 adults each five days. In flowers, it was observed that F. occidentalis feeding caused damage in the stamens and floral receptacle. In the unripe and ripe fruits it was observed russeting on the fruits basis, under the calyx and around the achenes. In the treatment where the insects were maintained during all the ripening period, only 17.6 percent of the fruits showed more than 40 percent of the area with russeting. Insect feeding causes russet in unripe and ripe fruits and fruit deformation are not associated with thrips presence of deformation.

Biologia e tabela de vida de fertilidade de Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae) em morangueiro / Biology and fertility life table of Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae) in strawberry

O objetivo deste trabalho foi estudar aspectos biológicos de Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae), considerando que no Brasil quase nada se sabe sobre a fauna de tripes associada à cultura do morangueiro. Larvas recém-eclodidas foram individualizadas em placas de Petri contendo uma flor ou um folíolo de morangueiro, mantidas em câmaras climatizadas (25 ± 1 ºC; 60 ± 10 por cento U.R.; fotofase de 12 horas) e observadas diariamente até a morte. A duração média do período de larva-adulto e a viabilidade não diferiram entre os insetos mantidos em flores (8,49 ± 0,18 e 68,52 por cento) e folíolos (8,85 ± 0,15 e 75,47 por cento). A fecundidade média diária e a total foram mais elevadas quando flores foram fornecidas como alimento (7,4 ± 0,69 e 70,0 ± 9,18 ovos/fêmea respectivamente), em comparação com folíolos (2,4 ± 0,35 e 8,5 ± 1,13 ovos/fêmea, respectivamente). A duração média, em dias, do período embrionário foi distinta entre os indivíduos mantidos em flores (3,7 ± 0,03) e em folíolos (4,4 ± 0,09). A viabilidade dos ovos depositados sobre flores e folíolos foi de 65,5 ± 0,01 e 74,3 ± 0,03 por cento, respectivamente. Com base na tabela de vida de fertilidade, o desempenho dos indivíduos de F. occidentalis que se desenvolveram em flores foi melhor, com uma geração (ovo-adulto) completada a cada 20,92 dias, a 25 °C.

This work aimed to study biological aspects of Frankliniella occidentalis (Pergande) (Thysanoptera, Thripidae) considering that almost nothing is known about the thrips fauna associated with strawberry crop. Newly hatched larvae were individualized into Petri dishes, containing a flower or a foliole of strawberry and kept in chambers (25 ± 1 °C, 60 ± 10 percent RH; 12 hours photophase). Daily observations were conducted until the insect death. The average time of the biological cycle (larva-adult) and viability did not differ between the insects maintained in flowers (8.49 ± 0.18 and 68.52 percent) and folioles (8.85 ± 0.15 and 75.47 percent). The daily and total average fecundity were higher when flowers were provided as food (7.4 ± 0.69 and 70.0 ± 9.18 eggs/femeale respectively) compared with folioles (2.4 ± 0.35 and 8.5 ± 1,13 eggs/femeale respectively). The average time, in days, of the embryonic period was significantly different for the insects reared in flowers (3.7 ± 0.03) than in folioles (4.4 ± 0.09). The viability of eggs deposited in flowers and folioles was 65.5 ± 0.01 and 74.3 ± 0.03 percent respectively. Based upon the fertility life table, the performance of F. occidentalis reared in flowers was better when compared to folioles. A generation (egg-adult) occurs each 20.92 days at 25 °C.

Anatomía de la agalla en Ficus benjamina (Moraceae) asociada a "thrips" (Tubulifera: Phlaeothripidae) / Gall anatomy in Ficus benjamina (Moraceae) associated with "thrips" (Tubulifera: Phlaeothripidae)

Anatomy of the gall in Ficus benjamina (Moraceae) associated with thrips (Tubulifera: Phlaeothripidae). The galls are generally recognized as abnormal growths of tissues affected by insects when lay the eggs or feed on plant tissues. In, Ficus benjamina the insect Gynaikothrips garitacambroneroi, when feeding on leaf tissues, causes a gall which consists on the bending of the leaves. In this paper we analyzed the ultrastructure of sections of healthy leaves, and leaves with galls of F. benjamina using scanning electron microscopy (SEM). We analyzed the number of stomata per area and found no significant changes, although there is less cuticular wax on the surface of the affected area by the barb. In the leaf area affected by G. garitacambroneroi, bacilli and fungi were observed and eggs of other organisms as possible invaders. Moreover, the inner tissues of leaves with galls had some problems in the differentiation of palisade and spongy mesophylls, and only parenchymatous tissue was observed. Rev. Biol. Trop. 57 (Suppl. 1): 179-186. Epub 2009 November 30.

Las agallas son reconocidas generalmente como crecimientos anormales de los tejidos afectados por insectos cuando estos realizan la deposición de los huevecillos o se alimentan de los tejidos de la planta. En Ficus benjamina la acción del thrips Gynaikothrips garitacambroneroi al alimentarse de los tejidos de la hoja, provoca una agalla que consiste en el doblamiento de la hoja. En este trabajo se analizó la ultraestructura de secciones de hojas sanas y hojas con agallas de F. benjamina mediante el uso de la microscopia electrónica de barrido. Se analizó la cantidad de estomas por área y no se determinó alteración significativa, aunque se observa menor cantidad de cera cuticular en la superficie del área afectada por la agalla. En la zona de la hoja afectada por G. garitacambroneroi se observó bacilos y hongos y huevecillos de otros organismos, aparentemente invasores. Además, en los tejidos internos de las hojas con agallas se pudo determinar problemas de diferenciación de los mesófilos de empalizada y esponjoso, observándose sólo tejido parenquimático.

Exigências térmicas e estimativa do número de gerações anuais de Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) em morangueiro / Thermal requirements and estimate of the annual number of generations of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) on strawberry crop

Frankliniella occidentalis (Pergande) é uma das principais pragas associadas à cultura do morangueiro no Sul do Brasil. O ataque do inseto à cultura resulta no murchamento de fl ores e bronzeamento de frutos. Neste trabalho, foi estimada a temperatura base e as exigências térmicas das fases de ovo, larva e pupa de F. occidentalis em morangueiro. Os insetos foram criados em folíolos da planta nas temperaturas de 16, 19, 22, 25, 28 e 31°C, em câmaras climatizadas (70 ± 10% U.R.; fotofase de 12h). O número de gerações anuais que F. occidentalis completa foi estimado para seis regiões produtoras de morango no Rio Grande do Sul (RS), com base nas exigências térmicas da espécie. A velocidade de desenvolvimento de F. occidentalis aumentou com a elevação da temperatura. A faixa mais adequada para o desenvolvimento da espécie foi entre 25ºC e 28ºC. A temperatura basee a constante térmica para o período ovo-adulto foi de 9,9ºC e 211,9 graus-dia, respectivamente. Com base nas exigências térmicas de F. occidentalis, foram estimados 10,7; 12,6; 13,1; 13,6; 16,5 e 17,9 gerações/ano, respectivamente, para as regiões produtoras de morangueiro de Vacaria, Caxias do Sul, Farroupilha, Pelotas, Porto Alegre e Taquari, RS.

Frankliniella occidentalis (Pergande) is one of the major strawberry pests in southern Brazil. The insect causes russeting and wither in fl owers and fruits reducing commercial value. Inthis work, the thermal requirements of the eggs, larvae and pupae of F. occidentalis were estimated. Thrips development was studied in folioles of strawberry plants at six constant temperatures (16, 19, 22, 25, 28 and 31°C) in controlled conditions (70 ± 10% R.H. and 12:12 L:D). The number of annual generations of F. occidentalis was estimated for six strawberry production regions of Rio Grandedo Sul State based on its thermal requirements. Developmental time of each F. occidentalis stages was proportional to the temperature increase. The best development rate was obtained when insects were reared at 25ºC and 28ºC. The lower threshold and the thermal requirements for the egg to adult stage were 9.9ºC and 211.9 degree-days, respectively. Considering the thermal requirements of F. occidentalis, 10.7, 12.6, 13.1, 13.6, 16.5 and 17.9 generations/year were estimated, respectively, for Vacaria, Caxias do Sul, Farroupilha, Pelotas, Porto Alegre and Taquari producing regions located in Rio Grande do Sul State, Brazil.

Calcium silicate and organic mineral fertilizer applications reduce phytophagy by Thrips palmi karny (Thysanoptera: thripidae) on eggplants (Solanum melongena L.) / Silicato de calcio y fertilizante organomineral influencian la fitofagia de thrips palmi (thysanoptera: thripidae) en plantas de berenjena (solanum melongena L) / Silicato de cálcio e fertilizante organomineral influenciam a fitofagia de thrips palmi (thysanoptera: thripidae) em plantas de berinjela (solanum melongena L)

Thrips palmi Karny (Thysanoptera: Thripidae) is a phytophagous insect associated with the reduction of eggplant productivity. The aim of this study was to evaluate the effect of calcium silicate and/or an organic mineral fertilizer, together or separately, in increasing the resistance of eggplants to T. palmi. The treatments were calcium silicate, organic mineral fertilizer, calcium silicate associated with this fertilizer and the control. Mortality and number of lesions caused by nymphs of this insect on eggplant leaves were evaluated after 3, 6, 9 and 12 leaf applications of these products. The calcium silicate and the organic mineral fertilizer reduced both the population of T. palmi and the damage caused by its nymphs, suggesting a possible increase in eggplant resistance to this pest as a result of the treatments.

Thrips palmi Karny (Thysanoptera: Thripidae) es un fitófago asociado a la reducción de productividad en el cultivo de berenjena. El objetivo del estudio fue evaluar el efecto del silicato de calcio y un fertilizante organomineral, individualmente y asociados, en el aumento de la resistencia de plantas de berenjena al T. palmi. Los tratamientos fueron silicato de calcio, fertilizante organomineral, silicato de calcio con fertilizante organomineral y testigo. La mortalidad y el número de lesiones de ninfas en las hojas de la planta de berenjena fueron evaluadas después de 3, 6, 9 y 12 aplicaciones foliares de los productos. El silicato de calcio y el fertilizante organomineral disminuyeron tanto la población de T. palmi como los daños producidos por las ninfas, mostrando un posible aumento de la resistencia de las plantas de berenjena a esa plaga.

Thrips palmi Karny (Thysanoptera: Thripidae) é um fitófago associado à redução da produtividade da berinjela. Dessa forma, objetivou-se avaliar o efeito do silicato de cálcio e de um fertilizante organomineral, isolados ou associados, no aumento da resistência de plantas de berinjela ao tripes T. palmi. Os tratamentos foram silicato de cálcio, fertilizante organomineral, silicato de cálcio associado com fertilizante organomineral e o controle. A mortalidade e o número de lesões de ninfas desse tripes nas folhas das plantas de berinjela foram avaliadas após três, seis, nove e doze aplicações foliares desses produtos. O silicato de cálcio e o fertilizante organomineral reduziram a população de T. palmi e os danos das ninfas, mostrando possível aumento da resistência das plantas de berinjela a essa praga.