ABSTRACT
Essential oils from the leaves and stems of Croton adenocalyx, C. grewioides, C. heliotropiifoliusand C. blanchetianus obtained through hydrodistillation were analyzed by GC-MS. We then investigated the lethal and sublethal effects of the Croton oils and 15 major constituents against Tetranychus urticae. ß-Caryophyllene was the major component in the leaf and stem oils from C. heliotropiifolius and C. adenocalyx. Spathulenol and (E)-anethole were the major constituents identified in the leaf and stem oils of C. blanchetianus and C. grewioides, respectively. The oil with the greatest lethal and sublethal effects was those from C. adenocalyx. Among the constituents ß-caryophyllene and spatulenol were the most toxic to the mite, where as eugenol and methyl eugenol were the most repellent. The toxicity and repellency of the Croton oils, particularly the oils from C. adenocalyx, demonstrate that these oils constitute a promising alternative to synthetic acaricides for use in the control of T. urticae.
Los aceites esenciales de las hojas y tallos de Croton adenocalyx, C. growioides, C. heliotropiifolius y C. blanchetianus obtenidos mediante hidrodestilación fueron analizados a través de GC-MS. Se investigaron los efectos letales y subletales de los aceites de Croton y 15 componentes principales contra Tetranychus urticae. El ß-cariofileno fue el componente principal en los aceites de hojas y tallos de C. heliotropiifolius y C. adenocalyx. El espatulenol y el (E)-anetol fueron los principales componentes identificados en los aceites de hojas y tallos de C. blanchetianus y C. growioides, respectivamente. El aceite con los mayores efectos letales y subletales fue el de C. adenocalyx. Entre los componentes, el ß-cariofileno y el espatulenol fueron los más tóxicos para el ácaro, mientras que el eugenol y el metil eugenol fueron los más repelentes. La toxicidad y la repelencia de los aceites de Croton, particularmente los aceites de C. adenocalyx, demuestran que estos aceites constituyen una alternativa prometedora respecto a los acaricidas sintéticos para uso en el control de T. urticae.
Subject(s)
Animals , Oils, Volatile/pharmacology , Croton/chemistry , Tetranychidae/drug effects , Acaricides/pharmacology , Terpenes/analysis , Oils, Volatile/chemistry , Chromatography, Gas/methods , Plant Leaves , Acaricides/chemistryABSTRACT
The aim of this study was to investigate the chemical composition and acaricidal effect of two Psidium species essential oils and selected compounds on Tetranychus urticae. Essential oils from the leaves of Psidium laruotteanum and Psidium myrsinites were obtained through hydrodistillation, analyzed using CG-FID and CG-MS and evaluated for toxicity to T. urticae by fumigation and residual contact. The susceptibility of T. urticae to monoterpenes and sesquiterpenes was also investigated. The major constituents of the P. laruotteanum oil were (E)-nerolidol (9.6 ± 0.4%) and γ-terpinene (9.4 ± 0.6%) and the major constituents of the P. myrsinites oil were ß-caryophyllene (21.2 ± 0.9%) and α-humulene (10.3 ± 0.5%). Based on the LC50 estimates, no significant differences were found between the two oils regarding toxicity by fumigation or residual contact. ß-Caryophyllene and (E)-nerolidol had the highest level of toxicity, independently of the method investigated. The findings indicate that both oils and selected constituents, especially ß-caryophyllene and (E)-nerolidol, are promising as natural acaricidal agents that affect T. urticae through more than one mode of action.
Los aceites esenciales de las hojas de Psidium laruotteanum y Psidium myrsinites se obtuvieron por hidrodestilación, se analizaron por CG-FID y CG-MS, y se evaluaron sus toxicidades por fumigación y contacto residual contra Tetranychus urticae. Se investigó también la susceptibilidad del T. urticae a monoterpenos y sesquiterpenos. En el aceite esencial de P. laruotteanum, (E)-nerolidol (9.6 ± 0.4%) y γ-terpinene (9.4 ± 0.6%) se identificaron como constituyentes mayoritarios, mientras que en el aceite esencial de P. myrsinites, ß-caryophyllene (21.2 ± 0.9%) y α-humulene (10.3 ± 0.5%) se encontraron como mayoritarios. Con base en las CL50 estimadas, no se observaron diferencias significativas entre las toxicidades de los aceites por fumigación, y tampoco por contacto residual. ßCaryophyllene y (E)-nerolidol presentaron las mayores toxicidades, independientemente del método investigado. Estos resultados indican, que los dos aceites, así como los constituyentes seleccionados, entre los que se destacan ß-caryophyllene y (E)-nerolidol, son promisores agentes acaricidas naturales por actuar en el T. urticae por más de un mecanismo de acción.
Subject(s)
Animals , Oils, Volatile/pharmacology , Plant Leaves/chemistry , Tetranychidae/drug effects , Psidium/chemistry , Acaricides/pharmacology , Terpenes/analysis , Brazil , Oils, Volatile/chemistry , Pest Control , Fumigation , Acaricides/chemistry , Flame Ionization , Gas Chromatography-Mass SpectrometryABSTRACT
Abstract Zoonoses are major causes of morbidity and mortality worldwide. Among them, Brazilian Spotted Fever (BSF) is an important one that occurs in some regions of South America and can be transmitted by the "star tick" Amblyomma sculptum. Application of acaricides against the larval stage is important as strategy of population control. However, there is still a deficiency of studies on chemical control of A. sculptum and the present work aims to evaluate the in vitro acaricidal activity of cypermethrin, flumethrin, deltamethrin, fipronil, coumaphos and chlorpyrifos against A. sculptum larvae. Bioassays were performed using the larval immersion test method. A discriminatory analysis between the antiparasitic classes most used for tick control was carried out, which made it possible to determine the classes with higher potential for controlling A. sculptum larvae. Our results showed that A. sculptum larvae present highest sensitivity to the synthetic pyrethroid group, followed by the phenylpyrazole, organophosphate and macrocyclic lactone groups. These findings may support studies on improvement of tick control as in animals as in the environment.
Resumo As zoonoses são a maior causa de morbidade de mortalidade no mundo. A Febre Maculosa Brasileira (FMB) é uma importante zoonose que ocorre em algumas regiões da América do Sul e pode ser transmitida pelo "carrapato-estrela" Amblyomma sculptum. A aplicação de acaricidas, frente ao estágio larval, é importante como estratégia no controle da população. No entanto, ainda há uma deficiência de estudos para o controle químico de A. sculptum. Devido à necessidade de mais informações sobre o controle de A. sculptum, o presente trabalho tem como objetivo avaliar a atividade acaricida in vitro de cipermetrina, flumetrina, deltametrina, fipronil, coumafós e clorpirifós frente a larvas de A. sculptum. Os bioensaios foram realizados pelo método Teste de Imersão de Larva. Foi realizada uma análise discriminatória entre as classes antiparasitárias mais utilizadas para controle de carrapatos, possibilitando determinar classes com maior potencial para o controle de larvas de A. sculptum. Os resultados deste trabalho mostraram que as larvas de A. sculptum apresentam maior sensibilidade ao grupo dos piretroides sintéticos, seguido pelos grupos fenilpirazóis, organofosforados e lactonas macrocíclicas. Esses achados poderiam apoiar estudos visando ao controle do carrapato tanto em animais quanto no meio ambiente.
Subject(s)
Animals , Ixodidae , Acaricides/classification , Acaricides/chemistry , South America , Rocky Mountain Spotted Fever/parasitology , Rocky Mountain Spotted Fever/prevention & control , Rocky Mountain Spotted Fever/transmission , LarvaABSTRACT
Rhipicephalus microplus, is one parasites that cause severe productivity losses in the cattle industry of Brazil and shows increasing resistance to conventional pesticides. This research aims to study the chemical composition, and acaricidal activity of the essential oil from Ocotea notata leaves, a brazilian endemic species, against R. microplus. The effect on R. microplus engorged adult females was evaluated using the immersion test. The oil reduced the survival by 90% after incubation for 15 days and there was 100% reduction for posture inhibition and reproductive capacity. These results suggest that the O. notata essential oil has activity on the R. microplus.
Rhipicephalus microplus, es un parásito que causa graves pérdidas de productividad en la industria ganadera de Brasil y muestra una creciente resistencia a los pesticidas convencionales. Esta investigación tiene como objetivo estudiar la composición química y la actividad acaricida del aceite esencial de las hojas de Ocotea notata, una especie endémica brasileña, contra R. microplus. El efecto sobre las hembras adultas engordadas de R. microplus se evaluó mediante la prueba de inmersión. El aceite redujo la supervivencia en 90% después de la incubación durante 15 días y hubo una reducción del 100% para la inhibición de la postura y la capacidad reproductiva. Estos resultados sugieren que el aceite esencial de O. notata tiene actividad contra R. microplus.
Subject(s)
Animals , Oils, Volatile/pharmacology , Ocotea/chemistry , Rhipicephalus/drug effects , Acaricides/pharmacology , Terpenes/analysis , Ticks/drug effects , Brazil , Oils, Volatile/chemistry , Tick Control/methods , Plant Leaves/chemistry , Lauraceae/chemistry , Acaricides/chemistry , Gas Chromatography-Mass SpectrometryABSTRACT
Abstract The Rhipicephalus (Boophilus) microplus tick is responsible for considerable economic losses in Brazil, causing leather damage, weight loss and reduced milk production in cattle and results in the transmission of pathogens. Currently, the main method for controlling this tick is using acaricides, but their indiscriminate use is one of the major causes of resistance dissemination. In this study, the adult immersion test (AIT) was used to evaluate resistance in ticks from 28 properties located in five different states (Mato Grosso do Sul, Mato Grosso, Ceará, São Paulo, e Minas Gerais) and the Distrito Federal (DF) of Brazil. The resistance was found in 47.64% of the repetitions demonstrating an efficacy of less than 90% in various locations throughout the country. The larvae packet test was used to evaluate samples from ten properties in four states (Mato Grosso do Sul, Mato Grosso, Minas Gerais and Espírito Santo). Spray products belonging to the main classes of acaricides, including combination formulations, were used in both types of test. New cases of resistance were found on properties within the states of Ceará, Espírito Santo and Mato Grosso, where such resistance was not previously reported.
Resumo O carrapato Rhipicephalus (Boophilus) microplus é responsável por consideráveis perdas econômicas no Brasil, causando, nos bovinos, danos ao couro, perda de peso, redução na produção de leite, o que resulta na transmissão também de patógenos. Atualmente, o principal método de controle para esse carrapato é o uso de acaricidas, porém seu uso indiscriminado é uma das principais causas da disseminação da resistência. Neste estudo, o teste de imersão de adultos (TIA) foi utilizado para avaliar a resistência em carrapatos provenientes de 28 propriedades, localizadas em cinco diferentes estados brasileiros (Mato Grosso do Sul, Mato Grosso, Ceará, São Paulo, e Minas Gerais) e no Distrito Federal (DF). A resistência foi encontrada em 47,64% das repetições, demonstrando uma eficácia de menos de 90% em vários lugares do país. O teste de pacote de larva foi utilizado para avaliar amostras de 10 propriedades em quatro estados (Mato Grosso do Sul, Mato Grosso, Minas Gerais e Espírito Santo). Produtos de pulverização, pertencentes às principais classes de acaricidas, incluindo-se associações, foram utilizados em ambos os testes. Novos casos de resistência foram encontrados em propriedades nos estados do Ceará, Espírito Santo e Mato Grosso, nas quais a resistência ainda não havia sido previamente reportada.