Insecticidal effect of clove and cinnamon essential oils in controlling weevil Acanthoscelides obtectus (Say) in beans

O feijão representa uma das principais fontes de proteínas em países em desenvolvimento, ainda assim as perdas estimadas no armazenamento são de 30% em consequência do ataque de pragas, entre elas Acanthoscelides obtectus (Say). Embora os pesticidas químicos sejam eficazes para controlar essas pragas, seu uso excessivo pode comprometer a qualidade dos alimentos. Óleos essenciais de origem vegetal são apresentados como uma alternativa atrativa aos inseticidas químicos sintéticos para o controle de pragas, porque apresentam pouco ou nenhum efeito sobre a qualidade dos grãos, saúde humana e meio ambiente. Este trabalho teve como objetivo avaliar a toxicidade dos óleos essenciais de Syzygium aromaticum (Myrtaceae) ou cravo e Cinnamomum zeylanicum (Laureaceae) conhecida como canela sobre A. obtectus em grãos de feijão (Phaseolus vulgaris L.). Avaliou-se a taxa instantânea de crescimento populacional (ri) desses insetos expostos a tempos- letais, taxa de desenvolvimento, repelência, persistência e perda de massa do feijão. A toxicidade dos óleos foi avaliada através de testes preliminares para estimar a dose letal para 50 e 95% (DL50 e DL95) dos insetos adultos. As unidades experimentais foram constituídas por frascos de 0,8 L contendo 200 g de feijão (variedade rainha) tratados com doses de 2,80; 5,54; 8,88; 14,22; 28,09 μL de óleo de cravo, e 4,26; 6,93; 9,70; 13,60; 22,17 μL de óleo de canela. Posteriormente, foram acrescentados 25 insetos adultos em cada frasco (quatro repetições por dose), e a mortalidade dos insetos foi avaliada após 24 h. A taxa instantânea de crescimento (ri) dos insetos na presença dos óleos de cravo e canela foi determinada utilizando as doses letais (DL10, DL30, DL50, DL70 e DL90), obtidas no bioensaio de toxicidade. Foram utilizados frascos com 200 g de feijão e 25 insetos adultos, não-sexados com idade de 1-3 dias, e quatro repetições por DL; após 45 dias, a progênie adulta foi contabilizada. Procedimento similar foi feito para avaliar a taxa de desenvolvimento, com a diferença de, que neste teste, os insetos foram retirados dos frascos depois de 15 dias de terem sido introduzidos, e a contagem foi realizada a cada dois dias após a emergência do primeiro adulto. A persistência foi avaliada em grãos de feijão tratados com a DL100 dos óleos. A atividade repelente dos óleos foi testada com as doses DL10, DL50, DL90 para cada óleo. Os resultados de toxicidade indicaram que as DL50 e DL95 foram 8,88 L e 38,94 L para o óleo essencial de cravo, e 9,70 L e 27,97 L para o óleo essencial de canela, respectivamente. Além disso, com o aumento das doses dos óleos essenciais, a ri e a taxa de desenvolvimento decrescem significativamente. Com relação à persistência dos óleos, observou-se a redução na mortalidade de A. obtectus com o aumento do tempo entre o tratamento dos grãos tratados; mantendo uma mortalidade superior ao 50% dos insetos até 7 dias após a exposição. Entretanto, foi observada repelência do óleo essencial de canela para este inseto somente ao utilizar-se a DL90; o óleo essencial de cravo não apresentou repelência contra A. obtectus nas doses testadas. A perda de massa dos grãos no período de 48 dias foi diretamente proporcional ao número de insetos emergidos em cada teste. Para o feijão tratado com óleo essencial de cravo, a perda média da massa foi de 6,6%, e no controle de 9,6%; nos ensaios com óleo essencial de canela, a perda média foi de 6,8% e 9,2% para os tratamentos e controle, respetivamente. Assim, com os resultados obtidos nesta pesquisa, pode-se concluir que os óleos essenciais de cravo e de canela têm efeito por contato na mortalidade de A. obtectus, sendo uma alternativa ao uso de inseticidas tradicionais.Beans are the major source of protein in developing countries, and still the storage losses are estimated in 30% as a result of pests attack including Acanthoscelides obtectus (Say). Although chemical pesticides are effective to control these pests, their overuse can compromise the quality of food. Essential oils of vegetable origin are presented as an attractive alternative for the synthetic chemical insecticides to pest control, because they have little or no effect on grain quality, human health and environment. This study aimed evaluate the toxicity of the essential oils of Syzygium aromaticum (Myrtaceae) or clove and Cinnamomun zeylanicum (Laureaceae) known as cinnamon on A. obtectus in beans (Phaseolus vulgaris L.). We evaluated the instantaneous rate of increase (ri) of these insects exposed to time-lethal, developmental rate, repellency, persistence and loss of mass of the beans. The toxicity of the oils was evaluated by preliminary tests to estimate the lethal dose to 50 and 95% (DL50 and DL95) of adult insects. The experimental unit consisted of 0.8 L bottles containing 200 g of beans (Queen variety) treated with doses of 2,80; 5,54; 8,88; 14,22; 28,09 μL of clove oil, and 4,26; 6,93; 9,70; 13,60; 22,17 μL of cinnamon oil. Later were added 25 adult insects per vial (four replicates per dose), and insect mortality was assessed after 24 h. The instantaneous rate of increase (ri) of the oils of clove and cinnamon was determined using lethal doses (LD10, LD30, LD50, LD70 and LD90), obtained in the toxicity bioassay. After 45 days, the adult progeny was recorded; bottles with 200 g of beans and 25 adult insects, non-sexed 1-3 days old, and four replicates were used for LD. A similar procedure was done to assess the rate of development, with the difference that in this test the insects were removed from the flasks after 15 days they were introduced, and counting was performed every two days after the emergence of the first adult. The persistence was evaluated in beans treated with LD100 oils. The repellent activity of oils was tested with the LD10, LD50, LD90 doses for each oil. The results indicate that the toxicity LD50 and LD95 were 8.88 L and 38.94 L for clove essential oil, and 9.71 L and 27.97 L for cinnamon essential oil, respectively. Furthermore, with increased doses of essential oils and ri, development rate decreases significantly. Regarding the persistence of oil, was observed mortality reduction of A. obtectus with increasing time between the treatments of treated grains, keeping a higher mortality at 50% of the insects within 7 days after exposure. However, repellency of essential oil of cinnamon to this insect was observed only when using LD90; clove essential oil showed no repellency against A. obtectus at the tested doses. The loss of grain weight during 48 days was directly proportional to the number of emerged insects in each test. For beans treated with clove essential oil the average of mass loss was 6.6%, and 9.6% in the control, whereas for tests with essential oil of cinnamon the average of loss was 6.8% and 9.2% for the treatment and control, respectively. Thus, with the results obtained in this study, it can be concluded that the essential oils of clove and cinnamon have effect on mortality of A. obtectus by contact, as an alternative to the use of traditional insecticides

Potential of diatomaceous earth as a management tool against Acanthoscelides obtectus infestations

The weevil Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae: Bruchinae) is a cosmopolitan pest that causes high losses in stored beans in small storage units and especially on-farm storages. Here, it was tested the efficacy of the inert dust diatomaceous earth (DE) as an alternative to control A. obtectus in common beans (i.e., Phaseolus vulgaris L.) on different storage temperatures and exposure intervals. Using a Completely Randomized design four doses (0.25, 0.50, 0.75 and 1.00g kg-1) of diatomaceous earth on beans kept at different temperatures (25, 28, 30, 32 and 35°C). Insect mortality was evaluated after two or five days of exposure. The impacts of diatomaceous earth in the offspring of five days-exposed A. obtectus adults were evaluated. The offspring production (emerged adults) was evaluated 60 days after the exposure. The results revealed that A. obtectus mortality caused by diatomaceous earth was dose, temperature and exposure period dependent. For instance, at the lowest temperature (25°C), diatomaceous earth dose (0.25g kg-1 of beans) and exposure period of two days, the efficacy of diatomaceous earth was significantly reduced when compared to the other treatments. When applied at temperatures above 30°C, the diatomaceous earth treatments always resulted in A. obtectus mortality of at least 90%. Curiously, offspring production (F1) was reduced to over 95% in all diatomaceous earth, temperatures and exposure period treatments. Therefore, the results demonstrated that diatomaceous earth has the potential to be used as a tool to manage A. obtectus infestations in stored beans, considering that such control practice adequately reduced these insect infestations in several possible scenarios.El gorgojo Acanthoscelides obtectus (Say) (Coleoptera: Chrysomelidae: Bruchinae) es una plaga cosmopolita que causa grandes pérdidas en frijoles almacenados, ya sea em pequenas unidades o en fincas. Aquí, se probó la eficacia del polvo inerte de la tierra de diatomeas (DE) como una alternativa para controlar A. obtectus en frijoles comunes Phaseolus vulgaris L., en diferentes temperaturas de almacenamiento e intervalos de exposición. Usando un diseño completamente al azar, cuatro dosis (0.25, 0.50, 0.75 y 1.00g kg-1) de tierra de diatomeas en frijoles mantenidos a diferentes temperaturas (25, 28, 30, 32 y 35 °C). La mortalidad de los insectos se evaluó después de dos o cinco días de exposición. Se evaluaron los impactos de la tierra de diatomeas en la descendencia de adultos de A. obtectus expuestos a cinco días. La producción de descendencia (adultos emergentes) se evaluó 60 días después de la exposición. Los resultados mostraron que la mortalidad por A. obtectus causada por la tierra de diatomeas dependía de la dosis, la temperatura y el período de exposición. Por ejemplo, a la temperatura más baja (25 °C), la dosis de tierra de diatomeas (0.25 g kg-1 de frijoles) y el período de exposición de dos días, la eficacia de la tierra de diatomeas se redujo significativamente en comparación con los otros tratamientos. Cuando se aplica a temperaturas superiores a 30 °C, los tratamientos con tierra de diatomeas siempre dieron como resultado una mortalidad de A. obtectus de al menos 90%. Curiosamente, la producción de descendencia (F1) se redujo a más del 95% en todos los tratamientos de tierra de diatomeas, temperaturas y períodos de exposición. Por lo tanto, los resultados demostraron que la tierra de diatomeas tiene el potencial de ser utilizada como una herramienta para controlar las infestaciones de A. obtectus en frijoles almacenados, considerando que dicha práctica de control redujo adecuadamente estas infestaciones de insectos en varios escenarios posible

Bioactividad de iridoides de Genipa americana contra el ácaro del cocotero Aceria guerreronis Keifer (Acari: Eriophyidae)

Genipap (Genipa americana L.) is a medicinal tree native to South America and the Amazon regions, where it is used as a popular traditional medicine. It is also highly consumed by people in the form of jams, juices, preserves, and wines. The aim of this study was to evaluate the toxicity, persistence, and the repellence properties of leaf methanolic extracts of genipap (LME) and its major iridoids (genipin and geniposide), against the key coconut pest mite Aceria guerreronis Keifer. The concentration-mortality bioassays revealed a strong acaricidal activity of LME against the coconut mite (LC50 = 0.60 mg.ml-1; and LC90 = 16.69 mg.ml-1). In addition, standard concentrations (0.6 mg.ml-1) of either genipin or geniposide killed 50 % and 62 % of the A. guerreronis, respectively, after 24 hours of exposure, highlighting the role of these iridoids in the acaricidal activity of LME. The persistence bioassays of LME revealed toxicity towards A. guerreronis for up to 36 hours after spraying. Furthermore, LC50 and LC90 of LME repelled the coconut mite after 1, 24, and 48 hours of exposure. Therefore, LME can be considered an alternative to assist in the integrated control of the coconut mite in coconut plantations.La planta de jagua (Genipa americana L.) es un árbol medicinal nativo de América del Sur y de la región Amazónica, donde se utiliza en la medicina popular y sus frutos son consumidos en forma de dulces, jugos, mermeladas y vinos. El objetivo de este trabajo fue evaluar la toxicidad, persistencia y repelencia del extracto metanólico de las hojas de Genipa americana (LME) y sus principales iridoides (genipina y geniposideo), contra la plaga clave de la palma de coco Aceria guerreronis Keifer. Los bioensayos de concentración-mortalidad revelaron una fuerte actividad acaricida de LME de G. americana al ácaro de la necrosis del cocotero (CL50 = 0,60 mg.ml-1 e CL90 = 16,69 mg.ml-1). Además, las concentraciones padrones (0,6 mg/ml-1) de extracto de genipina y geniposideo mataron 48 % y 52 %, respectivamente, de A. guerreronis después de 24 horas de exposición y se destacó la función de estos iridoides en la bioactividad de LME. Los bioensayos de persistencia de LME de G. americana revelaron toxicidad para A. guerreronis hasta 36 horas después de la pulverización. Además, las CL50 y CL90 del LME de G. americana repelieron el ácaro de la necrosis del cocotero después de 1, 24 y 48 horas de exposición. Así, el LME de esta planta puede ser considerado como una alternativa para auxiliar en el control integrado del ácaro de la necrosis A. gerreronis en plantaciones de coco

Bioactividad de iridoides de Genipa americana contra el ácaro del cocotero Aceria guerreronis Keifer (Acari: Eriophyidae)

Genipap (Genipa americana L.) is a medicinal tree native to South America and the Amazon regions, where it is used as a popular traditional medicine. It is also highly consumed by people in the form of jams, juices, preserves, and wines. The aim of this study was to evaluate the toxicity, persistence, and the repellence properties of leaf methanolic extracts of genipap (LME) and its major iridoids (genipin and geniposide), against the key coconut pest mite Aceria guerreronis Keifer. The concentration-mortality bioassays revealed a strong acaricidal activity of LME against the coconut mite (LC50 = 0.60 mg.ml-1; and LC90 = 16.69 mg.ml-1). In addition, standard concentrations (0.6 mg.ml-1) of either genipin or geniposide killed 50 % and 62 % of the A. guerreronis, respectively, after 24 hours of exposure, highlighting the role of these iridoids in the acaricidal activity of LME. The persistence bioassays of LME revealed toxicity towards A. guerreronis for up to 36 hours after spraying. Furthermore, LC50 and LC90 of LME repelled the coconut mite after 1, 24, and 48 hours of exposure. Therefore, LME can be considered an alternative to assist in the integrated control of the coconut mite in coconut plantations.La planta de jagua (Genipa americana L.) es un árbol medicinal nativo de América del Sur y de la región Amazónica, donde se utiliza en la medicina popular y sus frutos son consumidos en forma de dulces, jugos, mermeladas y vinos. El objetivo de este trabajo fue evaluar la toxicidad, persistencia y repelencia del extracto metanólico de las hojas de Genipa americana (LME) y sus principales iridoides (genipina y geniposideo), contra la plaga clave de la palma de coco Aceria guerreronis Keifer. Los bioensayos de concentración-mortalidad revelaron una fuerte actividad acaricida de LME de G. americana al ácaro de la necrosis del cocotero (CL50 = 0,60 mg.ml-1 e CL90 = 16,69 mg.ml-1). Además, las concentraciones padrones (0,6 mg/ml-1) de extracto de genipina y geniposideo mataron 48 % y 52 %, respectivamente, de A. guerreronis después de 24 horas de exposición y se destacó la función de estos iridoides en la bioactividad de LME. Los bioensayos de persistencia de LME de G. americana revelaron toxicidad para A. guerreronis hasta 36 horas después de la pulverización. Además, las CL50 y CL90 del LME de G. americana repelieron el ácaro de la necrosis del cocotero después de 1, 24 y 48 horas de exposición. Así, el LME de esta planta puede ser considerado como una alternativa para auxiliar en el control integrado del ácaro de la necrosis A. gerreronis en plantaciones de coco

Allyl isothiocyanate actions on populations of Sitophilus zeamais resistant to phosphine: Toxicity, emergence inhibition and repellency

Artigo da EntomologiaThe risks associated with the use of synthetic insecticides have caused increased interest in the research of essential oils and their main constituents for use in the pest management of stored products. Allyl isothiocyanate (AITC) is the main component of mustard essential oil and has been reported as a potential replacement pesticide for conventional insecticides that control stored product insect pests. Here, we assessed the toxicity (including emergence inhibition) and repellent actions of AITC on Brazilian populations of the maize weevil Sitophilus zeamais (Coleoptera: Curculionidae) resistant to conventional insecticides (e.g., phosphine). We also evaluated physiological (e.g., respiration) and behavioral (e.g., walking and flight) traits of AITC-exposed insects. The AITC showed consistent insecticidal activity against the populations resistant to phosphine and other synthetic insecticides, with LC50 values ranging from 1.5 to 2.9 μL L−1. Significant inhibition of the offspring emergence was achieved after the exposure of parental adults to sublethal levels (i.e., LC1 and LC5) of AITC. Reductions in respiration rates were also registered in all the populations sublethally exposed to AITC. In all five populations, a high number of insects avoided AITC-treated (1.5 μL L−1) grain masses, and although individuals of a phosphine-susceptible (i.e., Abre Campo) population increased walking and reduced flight activities, individuals of another phosphine-susceptible (i.e., Tunápolis) population exhibited higher flight activity under AITC exposure. Thus, our findings suggest that AITC is a potential tool that may be integrated into the control strategies of maize weevils where resistance to phosphine and other conventional insecticides is a problem

Toxicity to, oviposition and population growth impairments of Callosobruchus maculatus exposed to clove and cinnamon essential oils.

The use of plant essential oils has been shown to efficiently control insect pests of stored beans, significantly reducing the threats associated with synthetic insecticides. Here, we evaluated the potential of applications of essential oils of clove, Syzygium aromaticum L., and cinnamon, Cinnamomum zeylanicum L., to control Callosobruchus maculatus, considered as one of the most cosmopolitan pests of stored beans. Using four combinations of couples (i.e., unexposed couples, exposed females, exposed males, and exposed couples), we also evaluated how sublethal exposure to these essential oils impacted C. maculatus oviposition. Bioassays results revealed that both essential oils exhibited insecticidal activities similar to the synthetic pyrethroid insecticide deltamethrin. Furthermore, oil dosage increments proportionately decreased the growth rate and reduced the losses in bean weight caused by cowpea weevils, and offspring emergence was almost abolished when parents were exposed to the LD20 of each essential oil. Finally, significant oviposition impairments were perceived only in couples where females were exposed (i.e., females exposed and exposed couples) to the LD20 of cinnamon and clove essential oils. Thus, by exhibiting similar insecticidal activities as synthetic insecticides and by significantly affecting the oviposition of sublethally exposed C. maculatus females, the cinnamon and clove essential oils represent valuable tools with potential of integration into the management of C. maculatus infestations

Diversity and convergence of mechanisms involved in pyrethroid resistance in the stored grain weevils, Sitophilus spp.

Abstract Target-site mutations and changes in insect metabolism or behavior are common mechanisms in insecticide-resistant insects. The co-occurrence of such mechanisms in a pest strain is a prominent threat to their management, particularly when alternative compounds are scarce. Pyrethroid resistance among stored grain weevils (i.e., Sitophilus spp.) is an example of a long-standing concern, for which reports of resistance generally focus on a single mechanism in a single species. Here, we investigated pyrethroid resistance in maize and rice weevils (i.e., Sitophilus zeamais and S. oryzae), exploring potential knockdown resistance (kdr) mutations in their sodium channels (primary site for pyrethroid actions) and potential changes in their detoxification and walking processes. Resistance in pyrethroid-resistant rice weevils was associated with the combination of a kdr mutation (L1014F) and increases in walking and detoxification activities, while another kdr mutation (T929I) combined with increases in walking activity were the primary pyrethroid resistance mechanisms in maize weevils. Our results suggest that the selection of pyrethroid-resistant individuals in these weevil species may result from multiple and differential mechanisms because the L1014F mutation was only detected in Latin American rice weevils (e.g., Brazil, Argentina and Uruguay), not in Australian and Turkish rice weevils or Brazilian maize weevils

Dinâmica populacional e parasitismo natural de Diaphorina citri Kuwayama (Hemiptera: Liviidae) em pomares de citros em Sergipe

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Sternorrhyncha: Liviidae), which is the vector of the Hunglongbing (HLB) bacterium, has become a key citrus pest in Brazil. In addition to citrus, the ornamental plant known as Orange Jasmine, Murraya paniculata (L.) Jack, also hosts the psyllid. The present work aimed at studying the population dynamics of the psyllid in citrus orchards and its parasitism in citrus and M. paniculata in the state of Sergipe, the fourth largest citrus-producing state in Brazil. The evaluations were performed fortnightly for eleven months in seven Pera Citrus sinensis (L.) Osbeck orange orchards located in two municipalities of Sergipe state (Boquim, and Umbauba). The populations of eggs, nymphs and adults of D. citri were compared among all orchards and all developmental stages were related to the abiotic factors temperature, relative humidity and precipitation, in each locality. The psyllid was classified as an accessory species (not very abundant) in the orchards of Sergipe, showing a higher population density in November, December and March. Precipitation was the only abiotic factor that contributed to the population increase of adults of the psyllid. High rates of parasitism (55%) of psyllid nymphs by the exotic parasitoid Tamarixia radiata Waterston (Hymenoptera: Eulophidae) were detected in M. paniculata plants. Based on the results, if the HLB bacterium is detected in Sergipe, shorter samplings should be performed in the spring and summer months aiming at vector management. In addition, T. radiata could be released inundatively in integrated vector management programs.O psilídeo, Diaphorina citri Kuwayama (Hemiptera: Sternorrhyncha: Liviidae), por ser vetor da bactéria causadora do Hunglongbing (HLB), tornou-se uma praga-chave dos citros no Brasil. Além dos citros, a planta ornamental conhecida como murta-de-cheiro, Murraya paniculata (L.) Jack, também é hospedeira do psilídeo. O presente trabalho teve como objetivo estudar a dinâmica populacional do psilídeo em pomares de citros e o seu parasitismo em citros e murta-de-cheiro no estado de Sergipe, o quarto maior produtor de citros do Brasil. As avaliações foram realizadas quinzenalmente durante onze meses em sete pomares de laranjeira Pera Citrus sinensis (L.) Osbeck localizados em dois municípios (Boquim, e Umbaúba). As populações de ovos, ninfas e adultos de D. citri foram comparadas entre todos os pomares e todas as fases de vida foram relacionadas com os fatores abióticos, temperatura, umidade relativa e precipitação de cada localidade. O psilídeo D. citri foi classificado como espécie acessória (pouco abundante) nos pomares de Sergipe, apresentando maior densidade populacional nos meses de novembro, dezembro e março. A precipitação foi o único fator abiótico que contribuiu para o aumento populacional de adultos do psilídeo. Altas taxas de parasitismo (55 %) de ninfas do psilídeo pelo parasitoide exótico Tamarixia radiata Waterston (Hymenoptera: Eulophidae) foram detectadas em plantas de murta-de-cheiro. Com base nos resultados, caso a bactéria seja detectada em Sergipe, para o manejo do vetor, amostragens de menor intervalo deverão ser realizadas nos meses da primavera e verão. Adicionalmente, o parasitoide T. radiata poderia ser liberado inundativamente em programas de manejo integrado do vetor

Fumigant toxicity of eugenol and its negative effects on biological development of Callosobruchus maculatus L

The protection of stored products from insect damages, when accomplished, is mostly relying on the application of synthetic insecticides with serious health and environmental issues in addition to risks of selection of resistant insect populations associated with such practice. The use of plants derived compounds have been presented as sound strategy for sustainable insect pest management. Eugenol is an aromatic component of natural occurrence in essential oils of numerous plants. known for its repellent and insecticidal bioactivities against different insect species. Here, we investigated the fumigant application of eugenol to control the cowpea weevil Callosobruchus maculatus (Coleoptera: Chrysomelidae: Bruchinae) by assessing toxicity, effects on biological development (including emergence inhibition) and repellency to these weevil. Besides a good fumigant insecticidal activity, eugenol exposure resulted in  a dose-dependent decrease of  the growth rate of C. maculatus  associated with a steady reduction in bean mass losses. Additionally, inhibition of offspring was upper 50% when adults were exposed to lethal and sublethal concentrations. significant inhibition of the offspring emergence was achieved after the exposure of parental adults to lethal and sublethal doses of eugenol. Furthermore, adult weevils were repelled away from beans exposed to high dose (LD99) of eugenol in contrast with their attraction to the beans treated with lower dose (LD50).  Our findings suggest that eugenol has potential as control tool to be used in sustainable management startegies of C. maculatus

Bioactividad de aceites vegetales a Orthezia praelonga (Hemiptera: Sternorrhyncha: Orthezidae) y selectividad a su predador Ceraeochrysa caligata (Neuroptera: Chrysopidae)

Vegetable oils are abundant in oleaginous plants and they can be an alternative for the pest control in integrated management systems. Fatty acids present in these oils are bioactive to pests and they can be an alternative to the use of insecticides suggested to crops of citrus. Although these oils are of natural origin, the impact on beneficial species must be widely evaluated. Here, we evaluated the toxicity and repellency of crude oils of cotton, palm, soybean and coconut to a key citrus pest, Orthezia praelonga (Hemiptera: Sternorrhyncha: Ortheziidae), and its selectivity to Ceraeochrysa caligata (Neuroptera: Chrysopidade). Bioassays of concentration-mortality were performed under laboratory conditions and lethal concentrations of oils were estimated on O. praelonga adult females were estimated. Additionally, the repellent effect of each oil to the LC50 and LC80 was evaluated after 1.24, and 48 h. The four vegetable oils showed toxicity to O. praelonga: cotton LC50 = 1.92 μl/ml, palm oil LC50 = 2.54 μl/ml; soybean LC50 = 3.18 μl/ml and coconut LC50 = 5.02 μl/ml; and its selectivity to C. caligata was verified (CLs50 >80 % alive). Repellent effects of cotton oil (LC50 = 1.92 μl/ml, LC80 = 5.99 μl/ml), and palm oil (LC80 = 10.22 μl/ml) were demonstrated for one hour of exposure. In contrast, the soybean oil (LC80 = 12.50 μl/ml) repelled O. praelonga after 24 and 48 h of exposure. Results of toxicity, repellence and selectivity show the cotton, palm, and soybean oils as the most suitable for the control of O. praleonga.Los aceites vegetales abundan en plantas oleaginosas y pueden ser una alternativa para el control de plagas en sistemas de manejo integrado. Los ácidos grasos presentes en estos aceites muestran bioactividad a plagas y pueden ser una alternativa al uso de insecticidas recomendados para plantaciones de cítricos. Aunque estos aceites son de origen natural, el impacto en especies benéficas debe ser extensamente evaluado. Este estudio fue conducido a fin de evaluar la toxicidad y la repelencia de aceites crudos de algodón, dendé, soja desgomado y coco a una plaga clave de cítricos, Orthezia praelonga (Hemiptera: Sternorrhyncha: Ortheziidae), y su selectividad al predador Ceraeochrysa caligata (Neuroptera: Chrysopidae). Se realizaron bioensayos de concentración-mortalidad en condiciones de laboratorio y se estimaron concentraciones letales de los aceites sobre hembras adultas de O. praelonga. Adicionalmente, se evaluó el efecto repelente de cada aceite a la CL50 y CL80 después de 1, 24 y 48 h. Los cuatro aceites vegetales presentaron toxicidad a O. praelonga: algodón CL50=1,92 µl/ml, dendé CL50=2,54 µl/ml, soja CL50=3,18 µl/ml y coco CL50=5,02 µl/ml; su selectividad a C. caligata fue verificada (CLs50 >80 % de vivos). Se demostró el efecto repelente del aceite de algodón (CL50=1,92 µl/ml; CL80=5,99 µl/ml) y dendé (CL80=10,22 µl/ml) con una hora de exposición. Contrariamente, el aceite de soja desgomado (CL80=12,50 µl/ml) repelió a O. praelonga con 24 y 48 horas después de haber sido expuesta. Los resultados de toxicidad, repelencia y selectividad muestran al aceite vegetal de algodón, dendé y soja desgomado como los más adecuados para el control de O. praleonga