Author(s): FAZOLIN, M.; ESTRELA, J. V. E.; MONTEIRO, A. F. M.; SILVA, I. M. da; GOMES, L. P.; SILVA, M. S. de F.

Summary: 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 (LD50 and LC50) 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 LD50 or LC50, respectively) were prepared with sublethal doses or sublethal concentrations of the insecticides (below the LD40 or LC40). 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 CL50 and DL50 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 (SF = 8.46-17.22) 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.

Publication year: 2016

Types of publication: Journal article

Unit: Embrapa Acre

Keywords: Aceites esenciales, Botanical insecticides, Butóxido de piperonil, Butóxido de piperonila (PBO), Caterpillars, Dilapidol, Dilapiol, Essential oils, Homogeneidade, Homogeneity, Insect larvae, Insecticidas botánicos, Inseticida de origem vegetal, Inseticida organo-sintético, Lagarta, Lagarta do cartucho, Larvas de insectos, Oruga, Pesticide synergists, Pimenta de macaco, Piper aduncum, Piperaceae, Piperonyl butoxide, Plagas de plantas, Plant pests, Praga de planta, Sinergismo, Sinergismo de los plaguicidas, Spodoptera frugiperda, Óleo essencial