Combining the essential oil of Piper aduncum L. with commercial insecticides

Abstract

The use of synergists is important in minimizing the amount of chemical insecticide required for insect control. Their use can contribute to reducing environmental contamination and preserving beneficial insects. To further investigate a promising alternative to the synergist piperonyl butoxide (PBO), we compared the synergistic effects of PBO and Piper aduncum L. essential oil (PAEO) when combined with several insecticides (cypermethrin, zeta-cypermethrin, permethrin, and esfenvalerate) on the larvae of Spodoptera frugiperda (J. E. Smith, 1797). Initially, we determined the lethal doses and concentrations (LD 50 and LC 50 ) for S. frugiperda larvae subjected to separate treatments with PAEO and with each commercial insecticide. Subsequently, in order to evaluate the synergistic effect, combinations of sublethal doses or sublethal concentrations of the essential oil (½ and ¼ of the LD 50 or LC 50 , respectively) were prepared with sublethal doses or sublethal concentrations of the insecticides (below the LD 40 or LC 40 ). To confirm the evidence of the synergistic efficacy of the PAEO, the same reduced concentrations and doses of the insecticides that were previously used in combinations with the oil were also combined with PBO at a ratio of 10:1 (PBO:Insecticide). Through the relationship between the CL 50 and DL 50 of the insecticides taken separately and in their synergistic combinations with the PAEO and PBO, synergism factors (SF) were calculated for the various combinations. With residual contact, there was a significant enhancement of the commercial insecticides formulated with cypermethrin (SF = 73.03), zeta-cypermethrin (SF = 16.51), and permethrin ) when combined with the PAEO; by contrast, with topical application there was a significant enhancement only for zeta-cypermethrin (SF = 0.40-4.26), permethrin (SF = 2.10-4.79), and esfenvalerate (SF = 3.80) when combined with the essential oil. With the exception of esfenvalerate, the other synergistic combinations showed homogeneous responses for topical application and residual contact for at least one synergistic combination with PAEO. The significance of the SF values from combining PAEO with cypermethrin, zeta-cypermethrin, permethrin, and esfenvalerate insecticides may indicate that this essential oil is an effective alternative to PBO. Key words: Botanical synergistics. Cytochrome P-450. Esterases. Piperaceae. ResumoA importância da utilização de sinergistas está relacionada à minimização da quantidade de inseticida químico necessária para o controle de insetos, podendo contribuir com a diminuição da contaminação ambiental e preservação de insetos benéficos. Na busca de uma alternativa ao butóxido de piperonila (PBO), o estudo comparou os efeitos do PBO e do óleo essencial de Piper aduncum L. combinados com os inseticidas cipermetrina, permetrina e esfenvalerato, quanto ao efeito sinérgico e homogeneidade de resposta de larvas de Spodoptera frugiperda (J. E. Smith, 1797). Inicialmente foram determinadas as doses e concentrações letais (DL 50...

Respostas fisiológicas de plantas de orégano (<i>Origanum vulgare</i> L.) cultivadas sob malhas coloridas e fertilizantes orgânicos

“…Diferentes espécies vegetais comportam-se de maneiras distintas quando submetidas a diversas condições ambientais, assim como a hortelã-japonesa, onde as plantas cultivadas sem sombreamento acumularam mais MST (Chagas et al, 2013). Por outro lado, M. officinallis (Brant et al, 2009) e guaco (Souza et al, 2011) obtiveram aumento na produção de matéria seca quando crescidas sombreadas. Ao cultivar plantas de alecrim, Souza et al (2014) obtiveram maior produção de massa seca em plantas cultivadas em pleno sol, comparadas àquelas submetidas ao sombreamento.…”

“…A menor variação da umidade do ar podem ocasionar menor transpiração foliar nas plantas, já que, em ambientes protegidos ou parcialmente protegidos, há menor variação da umidade relativa do ar (Souza et al, 2011). Isto porque ambientes protegidos contribuem com o desenvolvimento dos vegetais, através do sinergismo entre radiação solar, temperatura e umidade do ar.…”

“…A luz e a fertilidade do solo exercem grande influência na produção vegetal (Seixas et al, 2013), percebe-se a necessidade do uso de alternativas para aumentar a produção destas plantas, em especial do orégano e, assim se beneficiar das condições ambientais favoráveis que o Brasil oferece, especialmente em relação à luminosidade. Neste sentido, técnicas que melhoram a qualidade da luz como o uso de malhas coloridas tem contribuído com o alterações na qualidade de luz do ambiente de cultivo e melhoria na fotossíntese, ocasionando maior eficiência de seu uso (Souza et al, 2011).…”

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“…Regarding the control of the fall armyworm, the studies are divided between studies with the essential oil of monkey's pepper, Piper aduncum L. (Piperaceae) (botanical insecticide), chemical insecticides and studies of synergistic effects between the two. Aiming to provide options for the management of S. frugiperda resistance to chemical insecticides, FAzOliN et al (2015bFAzOliN et al ( , 2016bFAzOliN et al ( , 2016cFAzOliN et al ( , 2017a evaluated the combination of the essential oil of P. aduncum with 15 conventional chemical active ingredients. AlmeidA et al (2017) analyzed the efficiency of six active ingredients mixed with copaiba oil-resin.…”

“…Complete information was published in the form of book chapters on the pest complexes associated with the cultivation and storage of beans in the Amazon (FAzOliN et al 2016c, as well as information for carrying out alternative pest control in their cultivation and storage. (FAzOliN et al 2016f).…”