323 research outputs found
Natural Biological Control of Lepidopteran Pests by Ants
The predatory ants (Hymenoptera: Formicidade) are social insects and important natural enemies of pests in agroecosystems. Despite the importance of these predators, little is known about their role, especially in tropical regions. Among the major Lepidopteran pests of vegetables are Ascia monuste (Pieridae), Diaphania nitidalis (Crambidae), Neoleucinodes elegantalis (Crambidae) and Tuta absoluta (Gelechiidae). Thus, this work aimed to study the natural biological control of A. monuste, D. nitidalis, N. elegantalis and T. absoluta by ants. For this, we evaluated the natural biological control of A. monuste on kale and D. nitidalis on cucumber both species in the dry season. Whilst the natural biological control of N. elegantalis and T. absoluta on tomato plants were evaluated in the rainy and dry seasons. Ants preyed on Lepidoptera in the pupa stadium. They also preyed on eggs of D. nitidalis. The activity of predatory ants occurred mainly during the night. The ants were the main causes of pupae mortality of A. monuste, D. nitidalis and T. absoluta. Beyond the ants, the physiological disturbances and birds were also important factors of pupae mortality of N. elegantalis. The ants Labidus coecus and Solenopsis sp. were observed preying on pupae whereas the Paratrechina sp. was observed preying eggs of D. nitidalis. The pupae mortality of D. nitidalis and T. absoluta by ants were higher than the pupae mortality of N. elegantalis and A. monuste. The rate of pupae predation of N. elegantalis by ants was similar in rainy and dry seasons and the same occurred with T. absoluta
Natural Biological Control of Diaphania spp. (Lepidoptera: Crambidae) by Social Wasps
The social wasps (Hymenoptera: Vespidae) are important agents of biological control for agricultural pests. Diaphania hyalinata L. and Diaphania nitidalis Cramer (Lepidoptera: Crambidae) are among the main pests of plants in the Cucurbitaceae family. Although the importance of social wasps is acknowledged, little is known about their activity as biological control agents in Diaphania spp. Thus, this work aimed to study the natural biological control of the caterpillars D. hyalinata and D. nitidalis by social wasps. We studied the natural biological control of caterpillars of D. hyalinata and D. nitidalis on cucumber hybrids Sprint 440 II and Vlasstar. The main predators of Diaphania caterpillars were the social wasps, followed by Diptera: Syrphidae; Hemiptera: Anthocoridae; Coleoptera: Coccinellidae, Anthicidae; Neuroptera: Chrysopidae and Arachnida: Araneae. Predation of D. hyalinata caterpillars by social wasps was high from the second to fifth instar. The predation of D. nitidalis caterpillars by social wasps was high from the second to fourth instar. There was no predation by social wasps on the first instar larvae of Diaphania spp. The cucumber hybrids did not influence the predation of Diaphania spp. by social wasps. The main social wasp predator of Diaphania spp. was Polybia ignobilis (Haliday). Also, we observed the social wasp Polybia scutellaris (White) preying on D. hyalinata but at low intensity.
OCORRÊNCIA DE TRIATOMINEOS (REDUVIIDAE: TRIATOMINAE) NO ESTADO DO AMAPÁ, BRASIL.
The triatomines are hematophagous insects which belong to the order Hemiptera, suborder Heteroptera, family Reduviidae and subfamily Triatominae, they are popularly known as barbeiro, chupança and other regional denominations. The epidemiological interest for the triatomines is related to the fact that these insects are vectors of the Trypanosoma cruzi, etiological agent of Chagas’ disease. The investigation was accomplished through the samples of triatomines in the entomologic collection of Iepa. This collection has a total of 32 samples of triatomines, which 21 are Rhodnius pictipes, 02 Panstrongylus geniculatus, 01 P. lignarius and 08 Eratyrus mucronatus. The species P. lignarius and E. mucronatus represent new records for the State of Amapá. The taxonomic identification and the publishing of this collection will contribute for the epidemiological analysis of the American Trypanosomiasis in Amapá, once; the recorded cases are conveyed only orally. It’s necessary the accomplishment of a most systematic studies, so that they will certainly reinforce a most significant sample of triatomines in the most varied ecotopes.Keywords: Triatominae; Epidemiology; Amazonian ecosystem; Classification; Amapá.Os triatomíneos são insetos hematófagos pertencentes à ordem Hemiptera, subordem Heteroptera, família Reduviidae e subfamília Triatominae, conhecidos popularmente como barbeiro, chupança e outras denominações regionais. O interesse epidemiológico pelos triatomineos está relacionado pelo fato desses insetos serem vetores do Trypanosoma cruzi, agente etiológico da doença de Chagas. A investigação foi realizada a partir dos exemplares de triatomíneos contidos na coleção entomológica do Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá - IEPA. Foram analisados um total de 32 exemplares de triatomíneos, dentre os quais 21 são Rhodnius pictipes, 02 Panstrongylus geniculatus, 01 P. lignarius e 08 Eratyrus mucronatus. As espécies P. lignarius e E. mucronatus representam novos registros para o Estado do Amapá. A identificação taxonômica e a divulgação deste acervo contribuirão para as análises epidemiológicas da Tripanosomíase Americana no Amapá, haja vista, que os casos registrados são atribuídos somente a transmissão oral. Faz-se necessário a realização de estudos mais sistemáticos, o que possibilitará certamente uma amostragem mais representativa de triatomíneos nos mais diversos ecótopos.Palavras-chave: Triatominae, Epidemiologia, Ecossistema Amazônico, Classificação, Amapá
Immunochromatography screening devices for cannabinoids in oral fluid sample
Cannabis sativa L. is one of the most consumed drugs in the world and recent studies have associated its use with an increase in the number of traffic accidents in different countries. In many countries, like Brazil, simple and reliable methodologies are still needed for the detection of drugs on site, mainly cannabinoids, considering its prevalence of use and oral fluid (OF) has been proved as an appropriate biological matrix for this purpose. Considering that, this work aims to review previous studies on immunochromatographic devices for on-site detection of cannabinoids in OF, discussing their sensitivity, specificity, cut-offs values and confirmatory methods. This data shows the importance of choosing a screening device and it reinforces the need for its implementation in Brazil. The research was conducted on 5 databases and all original articles, published in the last 10 years, were selected. A total of 32 articles were found, providing data for 17 screening devices of distinct brands. Only 2 screening devices showed satisfactory sensitivity and specificity in the evaluated studies (≥80% and ≥90% respectively). However, it should be considered that the screening devices still have some limitations, such as a higher cut-off than those recommended by international guidelines (cut-off > 2 ng/mL), therefore demonstrating the need for more studies in the area and the importance of confirmatory analysis usually fulfilled by LC-MS/MS, GC-MS/MS or GC-MS. Thus, the screening analyzes should not be evaluated by itself, but in association with confirmatory results and observational traits (behavioral changes), for a better understanding of the traffic scenario
Insect phitophagous and predators incidence on maize and bean cultivated in exclusive and intercropped systems
Este trabalho foi conduzido em Coimbra, MG, no ano agrícola 1996/97 e objetivou avaliar a ocorrência de insetos fitófagos e de predadores no milho e no feijoeiro cultivados em sistema exclusivo e em policultivo. Foi realizado um cultivo de milho (25/10/1996 a 24/03/1997) e dois cultivos de feijão [o primeiro de 25/10/1996 a 20/01/1997 (cultivo "das águas") e o segundo de 25/03/1997 a 21/07/1997 (cultivo "da seca")]. Realizaram-se contagens diretas das populações de insetos fitófagos e de predadores nas culturas. Menores densidades populacionais de herbívoros considerados preferenciais da cultura do milho [Dalbulus maidis (Delong & Wolcott) (Homoptera: Cicadellidae) e Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)] e do feijoeiro [Diabrotica speciosa (Germ.), Cerotoma arcuata (Oliv.) (Coleoptera: Chrysomelidae) e Empoasca kraemeri (Ross & Moore) (Homoptera: Cicadellidae)] estiveram associadas ao cultivo consorciado. As densidades de herbívoros generalistas como Thrips tabaci Lind. (Thysanoptera: Thripidae) e Pseudoplusia includens (Walk.) (Lepidoptera: Noctuidae) foram maiores no feijoeiro consorciado com o milho. No cultivo "das águas", o total de insetos fitófagos foi maior no feijoeiro consorciado com o milho do que no feijoeiro cultivado exclusivamente, sendo que o inverso ocorreu no cultivo "da seca". Os predadores Anthicus sp. (Coleoptera: Anthicidae) e Hymenoptera: Formicidae foram mais abundantes no milho e no feijoeiro cultivados exclusivamente do que as culturas foram consorciadas. _____________________________________________________________________________________ ABSTRACTThis work was carried out in Coimbra, MG,Brazil, during the agricultural year of 1996/97 and it had the objective of evaluating the phytophagous insects and predators occurrence in maize and bean cultivated in exclusive and policultive systems. One cultivation of maize (from 10/25/1996 to 03/24/1997) and two cultivation of bean were conducted [the first one from 10/25/1996 to 01/20/1997 (rainy period cultivation) and the second one from 03/25/1997 a 07/21/1997 (drought period cultivation)]. The population of phytophagous insects and predators incident in the cultures were counted directly. Lower herbivores population density, which attacks preferentially maize [Dalbulus maidis (Delong & Wolcott) (Homoptera: Cicadellidae) and Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae)] and bean [Diabrotica speciosa (Germ.), Cerotoma arcuata (Oliv.) (Coleoptera: Chrysomelidae) and Empoasca kraemeri (Ross & Moore) (Homoptera: Cicadellidae)] were associated to the intercropped system. The generalists-insect densities as Thrips tabaci Lind. (Thysanoptera: Thripidae) and Pseudoplusia includens (Walk.) (Lepidoptera: Noctuidae) were higher in the bean intercropped with maize. The phytophagous-insect total number was higher in the bean intercropped with maize in the rainy period cultivation than in the bean cultivated exclusively. The opposite happened in the drought period cultivation. The predators Anthicus sp. (Coleoptera: Anthicidae) and Hymenoptera: Formicidae were more abundant in the maize and bean cultivated exclusively than when the cultures were cultivated intercropped
Evaluation of synergistic action between nimesulide and the antifungals ketoconazole and nystatin on clinical cervical-vaginal isolates of Candida spp.
Introduction: Antifungal resistance in cases of vulvovaginal candidiasis (VVC) increasingly affects women worldwide, being a recurrence in gynecological appointments. The need for effective new therapies and the difficulty of introducing antifungals into the pharmaceutical market makes drug combination a quick and interesting therapeutic strategy for solving such a problem. Objective: The present study aims to evaluate the association of nimesulide, a non-steroidal anti-inflammatory drug, with antifungals used in topical treatments for vaginal candidiasis (ketoconazole and nystatin). Secondarily, we link the susceptibility profile of clinical isolates from primary health care units in southern Brazil. Materials and methods: The broth micro dilution methodology was used for susceptibility testing, and the Checkerboard method was used to evaluate the synergistic effect of nimesulide with antifungals. Results and discussions: High percentages of isolates resistant to the tested antifungals were observed: 75% of the isolates were resistant to fluconazole and 36.1% to Iitraconazole, as well as 22.2% had low susceptibility to ketoconazole and 55% to nystatin. The combination of nimesulide and ketoconazole showed synergistic effect for 62.5% of Candida spp. tested, including C. albicans, C. glabrata and C. tropicalis isolates. On the other hand, the combination of nimesulide and nystatin resulted in 100% indifference
Experimental analysis of mechanical and permeability characteristics of pervious concrete with incorporation of Açaí seeds/Análise experimental das características mecânicas e de permeabilidade do betão permeável com incorporação de sementes de Açaí
Açaí is a typical Brazilian fruit that has getting increasing attention and demand worldwide. Nevertheless, this fruit results in environmental issues, since that the growing consume brings along with the seeds, which are treated as urban solid residues in the city of Belém, Pará state, and further açaí production poles. In this sense, this work aims to analyze the incorporation of this residue as coarse aggregate to the composition of a pervious concrete, generating a possible environmental solution in two fronts: firstly to the inadequate disposal of açaí residual on the streets, and secondly to the constant flooding events in Brazil. In this way, permeability, compression and indirect traction experiments in tests bodies were carried out, according to the Brazilian Association of Technical Norms - ABNT, in order to determine the feasibility of pervious concrete with açaí seeds when compared to a reference pervious concrete. Concluding that this material has potential for satisfactory applications for many construction demands
Componentes químicos associados à resistência de Lycopersicon hirsutum f. typicum a Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae)
Este trabalho foi conduzido em casa de vegetação no Campus da Universidade Federal de Viçosa, Minas Gerais, Brasil de maio a setembro de 1997 e objetivou estudar a resistência do acesso LA 1777 de Lycopersicon hirsutum f. typicum a Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) e os prováveis compostos químicos envolvidos na resistência. Utilizaram-se as cultivares de Santa Clara (tomate para consumo in natura) e IPA-5 (tomate industrial) de Lycopersicon esculentum como padrões de suscetibilidade à praga. Avaliaram-se os números de minas pequenas (comprimento 0,5 cm); sobrevivência, estádio de desenvolvimento do inseto, peso de pupas, proporção sexual, fertilidade de adultos e a taxa de eclosão de larvas. Foram identificados picos nas correntes de íons do extrato hexânico das folhas e as prováveis substâncias associadas a estes utilizando-se cromatógrafo a gás acoplado a espectrômetro de massa. L. hirsutum f. typicum apresentou resistência à traça do tomateiro em relação a L. esculentum, o que refletiu em menor número de minas grandes/folha e maiores duração da fase larval, mortalidade de larvas e número de minas pequenas de T. absoluta. Foram identificados 14 picos nas correntes de íons, com tempos de 10,43 (pico 1) a 26,03 min. (pico 14). Os picos 8, 9, 10 e 12 estiveram relacionados com a resistência de L. hirsutum f. typicum a T. absoluta. O pico 14 ocorreu apenas na cultivar Santa Clara e esteve associado ao aumento da suscetibilidade do tomateiro a T. absoluta. Os prováveis compostos associados ao pico oito foram os sesquiterpenos 2,5,5-trimetil-1,3,6-heptatrieno, (+) canfeno, farneseno ou santalol. As prováveis substâncias associadas ao pico nove foram os sesquiterpenos α-bergamoteno, farneseno, β-sinesal e farnesol. Não foram encontradas substâncias prováveis associadas aos picos 10, 12 e 14.This work was carried out in a greenhouse at the Universidade Federal de Viçosa "Campus", Minas Gerais, Brazil, between May and September 1997 and its objective was study the resistance of the accession LA 1777 of Lycopersicon hirsutum f. typicum to Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) and the compounds possibly involved in the resistance. The varieties Santa Clara (tomato for in natura consumption) and IPA-5 (industrial tomato) of Lycopersicon esculentum were used as pest susceptibility standards. The number of small and large mines ( 0.5 cm long, respectively); survival; development stage; pupa weight; sexual proportion; fertility, and rate of larvae eclosion were assessed. Peaks of the ion current of hexane extract of tomato leaves and the possible compounds associated with them were identified using a gas chromatograph coupled to a mass spectrometer. L. hirsutum f. typicum showed resistance to the tomato leafminer in comparison with L. esculentum, what was reflected by the smaller number of large mines/ leaf and greater length of larval phase, mortality of larvae and number of small mines of T. absoluta. Fourteen peaks were identified in the total ion current with retention times ranging from 10.43 (peak 1) to 26.03 min (peak 14). The peaks 8, 9, 10 and 12 were associated with T. absoluta resistance in L. hirsutum f. typicum. The peak 14 occurred only in the variety Santa Clara with an increased tomato susceptibility to T. absoluta. The probable compounds associated with peak 8 were the sesquiterpenes 2,5,5-trimethyl-1,3,6-heptatriene, (+) camphene, farnesene or santalol. The probable substances associated with peak 9 were the sesquiterpenes α-bergamotene, farnesene, β-sinesal, or farnesol. No substance associated with peaks 10, 12 and 14 were found
Control failure likelihood and spatial dependence of insecticide resistance in the tomato pinworm, Tuta absoluta
Insecticide resistance is a likely cause of field control failures of Tuta absoluta, but the subject has been little studied. Therefore, resistance to ten insecticides was surveyed in seven representative field populations of this species. The
likelihood of control failures was assessed, as well as weather influence and the spatial dependence of insecticide resistance. No resistance or only low resistance levels were observed for pyrethroids (bifenthrin and permethrin), abamectin, spinosad, Bacillus thuringiensis and the mixture deltamethrin + triazophos (<12.5-fold). In contrast, indoxacarb exhibited moderate levels of resistance (up to 27.5-fold), and chitin synthesis inhibitors exhibited moderate to high levels of resistance (up to 222.3-fold). Evidence of control failures was obtained for bifenthrin, permethrin, diflubenzuron, teflubenzuron, triflumuron and B. thuringiensis. Weather conditions favour resistance to some insecticides, and spatial dependence was observed only for
bifenthrin and permethrin. Insecticide resistance in field populations of the tomato pinworm prevails for the insecticides nowadays most frequently used against them – the chitin synthesis inhibitors (diflubenzuron, triflumuron and teflubenzuron). Local selection favoured by weather conditions and dispersal seem important for pyrethroid resistance evolution among Brazilian populations of T. absoluta and should be considered in designing pest management programmes
PRIMEIRO REGISTRO DE Cymothoa sp. FABRICIUS, 1793 (ISOPODA: CYMOTHOIDAE) PARASITANDO O PEIXE DE QUATRO OLHOS, Anableps anableps (CYPRINODONTIFORMES: ANABLEPIDAE), NA COSTA NORTE BRASILEIRA
This study presents the first record of the occurrence of Cymothoa Fabricius, 1793 in northern Brazil, as well as in four-eyed fish Anableps anableps. The research was conducted in the Curuçá estuary, in northern Brazil, where 158 specimens of A. anableps were collected, with nine Cymothoa specimens being found on nine different fish. These isopods were identified by sequencing the mitochondrial Cytochrome Oxidase I gene. The prevalence of the parasite (4.43 %) in A. anableps was extremely low and Cymothoa sp. specimens were found primarily in the gills of the host fish.Keywords: Amazon; Isopoda; Crustaceans; Four-Eyed Fish; Anablepidae.Este estudo apresenta o primeiro registro da ocorrência de Cymothoa Fabricius, 1793 no norte do Brasil, bem como no peixe de quatro olhos Anableps anableps. A pesquisa foi realizada no estuário de Curuçá, no norte do Brasil, onde foram coletados 158 espécimes de A. anableps, com nove espécimes de Cymothoa, sendo encontrados em nove peixes diferentes. Esses isópodes foram identificados pelo sequenciamento do gene mitocondrial do citocromo oxidase I. A prevalência do parasita (4.43 %) em A. anableps foi extremamente baixa e os espécimes de Cymothoa foram encontrados principalmente nas brânquias do peixe hospedeiro.Palavras-chave: Amazônia, Isopoda, Crustáceos, Peixe com quatro olhos, Anablepidae
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