Toxicity of Piper aduncum (Piperaceae) Essential Oil Against Euschistus heros (F.) (Hemiptera: Pentatomidae) and Non-Effect on Egg Parasitoids.

Plant essential oils have been recognized as significant natural resources for insecticides. Herein, we have assessed the toxicity of the essential oil of Piper aduncum (Piperaceae) against Euschistus heros (F.) (Hemiptera: Pentatomidae), a key soybean pest in Neotropical America. In addition, we have assessed its effect on the performance of egg parasitoids. The essential oil was obtained from the leaves of P. aduncum via hydrodistillation. Subsequently, bioassays of the concentration response to eggs (contact and immersion methods), nymphs, and adults (topical application) were conducted, to assess the lethal effects on the stink bug. We also evaluated the performance of parasitism and adult emergence of egg parasitoids, when the host eggs were treated with essential oil. In the egg bioassay, both exposure methods were efficient for unviable eggs (immersion LC50 = 15.64 mg mL-1; contact LC50 = 21.29 mg mL-1), with the highlight on the immersion method. The bioassay with nymphs indicated a higher toxicity of essential oil, with lower concentrations (LC50 = 11.37 mg mL-1) being required to cause the death of insects. For adults, a reduction in survival of insects was observed, and consequently, there was a reduction in the number of individuals in the next generation. Although the essential oil was toxic to E. heros, it exhibited lower toxicity for egg parasitoids, as there was no effect on parasitism and the emergence of wasps. We discuss likely explanations for such selectivity. In summary, we found that the essential oil was promising for the control of E. heros, because it caused deleterious effects at all development stages of the stink bug and had no effect on parasitism and emergence of the egg parasitoids, which suggested compatibility with biological control.

Morphological changes in the midgut of Aedes aegypti L. (Diptera: Culicidae) larvae following exposure to an Annona coriacea (Magnoliales: Annonaceae) extract.

Bioinsecticides are important in the control of disease vectors, but data regarding their physiological effects on target insects are incomplete. This study describes morphological changes that occur in the midgut of third instar Aedes aegypti L. (Diptera: Culicidae) following treatment with a methanolic extract of Annona coriacea (Magnoliales: Annonaceae). Dissected midguts were subdivided into anterior and posterior regions and analyzed by light and scanning electron microscopy. Insects exposed to the extract displayed intense, destructive cytoplasmic vacuolization in columnar and regenerative midgut cells. The apical surfaces of columnar cells exhibited cytoplasmic protrusions oriented toward the lumen, suggesting that these cells could be involved in apocrine secretory processes and/or apoptosis. We report that A. coriacea extracts induced morphological alterations in the midgut of A. aegypti midgut larvae, supporting the use of plant extracts for control of the dengue vector.

Efeito residual do extrato de Annona coriacea sobre Aedes aegypti / Residual effect of Annona coriacea extract on Aedes aegypti

A produção de extratos vegetais da família Annonaceae é uma alternativa eficaz no controle do vetor da dengue, e sua aplicabilidade está relacionada à persistência do produto no ambiente. O objetivo desta pesquisa foi avaliar o efeito residual do extrato de Annona coriacea (Mart., 1841) sobre a mortalidade de Aedes aegypti (Linnaeus, 1762). Foram utilizados recipientes plásticos de 25 L, para distribuir as concentrações de 50 e 100 ppm do extrato, e DMSO (1%) e água foram usados como controle. Estes recipientes ficaram expostos na área externa do laboratório. Nos dias 1, 8, 15, 30 e 45 dias após o preparo, coletou-se uma amostra de 1,3 L de cada tratamento. Foram utilizadas oito réplicas com 25 larvas de A. aegypti para os dois tratamentos, e quatro réplicas para os controles. O registro da mortalidade das larvas foi feito diariamente e foi observada a mortalidade de pupas e adultos. O experimento foi conduzido aleatoriamente, no esquema fatorial 4 x 5. Os dados foram submetidos à análise de variância pelo teste F e as médias dos tratamentos foram comparadas pelo teste de Tukey (p < 0,05). A concentração de 100 ppm do extrato de A. coriaceaapresentou efeito residual de 100% de mortalidade de larvas durante o período de 15 dias, e não houve eficiência na mortalidade de pupas e adultos. Portanto, o efeito residual apresentado por A. coriacea sobre larvas de A. aegypti indica que o extrato desta planta pode ser utilizado em programas de controle da dengue. (AU)

RESIDUAL EFFECT OF ANNONA CORIACEA EXTRACT ON AEDES AEGYPTI. The production of extracts of the Annonaceae family is considered an effective alternative for the control of the dengue vector, and its applicability is related to the persistence of the product in the environment. The aim of the present study was to evaluate the residual effect of Annona coriacea (Mart., 1841) extract on the development of Aedes aegypti (Linneaus, 1762). Plastic containers with the capacity of 25 liters were used to distribute the concentrations of 50 and 100 ppm of the extract, and DMSO (1%) and water were used as a control. These containers were exposed in the outer area of the laboratory. On days 1, 8, 15, 30, 45 after treatment application, 1.3 liters of each treatment was collected as a sample. Eight replicates with 25 larvae were applied for the two treatments, and four replicates for the control group. Evaluation of the mortality of larvae was carried out daily and the mortality of pupae and adults was observed. The experiment was conducted randomly in a 4 X 5 factorial scheme. The data was submitted to analysis of variance by F test, and the means compared by Tukey Test (p < 0.05). The concentrations of 100 ppm of the extract of A. coriacea showed residual effects with 100% mortality of larvae during the period of 15 days, and was not effective on the death of pupae and adults. Therefore, the residual effect presented by A. coriacea on A. aegypti can be used in future management programs for controlling the vector of dengue. (AU)

Efeito residual do extrato de Annona coriacea sobre Aedes aegypti

The production of extracts of the Annonaceae family is considered an effective alternative for the control of the dengue vector, and its applicability is related to the persistence of the product in the environment. The aim of the present study was to evaluate the residual effect of Annona coriacea (Mart., 1841) extract on the development of Aedes aegypti (Linneaus, 1762). Plastic containers with the capacity of 25 liters were used to distribute the concentrations of 50 and 100 ppm of the extract, and DMSO (1%) and water were used as a control. These containers were exposed in the outer area of the laboratory. On days 1, 8, 15, 30, 45 after treatment application, 1.3 liters of each treatment was collected as a sample. Eight replicates with 25 larvae were applied for the two treatments, and four replicates for the control group. Evaluation of the mortality of larvae was carried out daily and the mortality of pupae and adults was observed. The experiment was conducted randomly in a 4 X 5 factorial scheme. The data was submitted to analysis of variance by F test, and the means compared by Tukey Test (p 0.05). The concentrations of 100 ppm of the extract of A. coriacea showed residual effects with 100% mortality of larvae during the period of 15 days, and was not effective on the death of pupae and adults. Therefore, the residual effect presented by A. coriacea on A. aegypti can be used in future management programs for controlling the vector of dengue.

A produção de extratos vegetais da família Annonaceae é uma alternativa eficaz no controle do vetor da dengue, e sua aplicabilidade está relacionada à persistência do produto no ambiente. O objetivo desta pesquisa foi avaliar o efeito residual do extrato de Annona coriacea (Mart., 1841) sobre a mortalidade de Aedes aegypti (Linnaeus, 1762). Foram utilizados recipientes plásticos de 25 L, para distribuir as concentrações de 50 e 100 ppm do extrato, e DMSO (1%) e água foram usados como controle. Estes recipientes ficaram expostos na área externa do laboratório. Nos dias 1, 8, 15, 30 e 45 dias após o preparo, coletou-se uma amostra de 1,3 L de cada tratamento. Foram utilizadas oito réplicas com 25 larvas de A. aegypti para os dois tratamentos, e quatro réplicas para os controles. O registro da mortalidade das larvas foi feito diariamente e foi observada a mortalidade de pupas e adultos. O experimento foi conduzido aleatoriamente, no esquema fatorial 4 x 5. Os dados foram submetidos à análise de variância pelo teste F e as médias dos tratamentos foram comparadas pelo teste de Tukey (p 0,05). A concentração de 100 ppm do extrato de A. coriacea apresentou efeito residual de 100% de mortalidade de larvas durante o período de 15 dias, e não houve eficiência na mortalidade de pupas e adultos. Portanto, o efeito residual apresentado por A. coriacea sobre larvas de A. aegypti indica que o extrato desta planta pode ser utilizado em programas de controle da dengue.

Efeito residual do extrato de Annona coriacea sobre Aedes aegypti / Residual effect of Annona coriacea extract on Aedes aegypti

A produção de extratos vegetais da família Annonaceae é uma alternativa eficaz no controle do vetor da dengue, e sua aplicabilidade está relacionada à persistência do produto no ambiente. O objetivo desta pesquisa foi avaliar o efeito residual do extrato de Annona coriacea (Mart., 1841) sobre a mortalidade de Aedes aegypti (Linnaeus, 1762). Foram utilizados recipientes plásticos de 25 L, para distribuir as concentrações de 50 e 100 ppm do extrato, e DMSO (1%) e água foram usados como controle. Estes recipientes ficaram expostos na área externa do laboratório. Nos dias 1, 8, 15, 30 e 45 dias após o preparo, coletou-se uma amostra de 1,3 L de cada tratamento. Foram utilizadas oito réplicas com 25 larvas de A. aegypti para os dois tratamentos, e quatro réplicas para os controles. O registro da mortalidade das larvas foi feito diariamente e foi observada a mortalidade de pupas e adultos. O experimento foi conduzido aleatoriamente, no esquema fatorial 4 x 5. Os dados foram submetidos à análise de variância pelo teste F e as médias dos tratamentos foram comparadas pelo teste de Tukey (p < 0,05). A concentração de 100 ppm do extrato de A. coriaceaapresentou efeito residual de 100% de mortalidade de larvas durante o período de 15 dias, e não houve eficiência na mortalidade de pupas e adultos. Portanto, o efeito residual apresentado por A. coriacea sobre larvas de A. aegypti indica que o extrato desta planta pode ser utilizado em programas de controle da dengue.

RESIDUAL EFFECT OF ANNONA CORIACEA EXTRACT ON AEDES AEGYPTI. The production of extracts of the Annonaceae family is considered an effective alternative for the control of the dengue vector, and its applicability is related to the persistence of the product in the environment. The aim of the present study was to evaluate the residual effect of Annona coriacea (Mart., 1841) extract on the development of Aedes aegypti (Linneaus, 1762). Plastic containers with the capacity of 25 liters were used to distribute the concentrations of 50 and 100 ppm of the extract, and DMSO (1%) and water were used as a control. These containers were exposed in the outer area of the laboratory. On days 1, 8, 15, 30, 45 after treatment application, 1.3 liters of each treatment was collected as a sample. Eight replicates with 25 larvae were applied for the two treatments, and four replicates for the control group. Evaluation of the mortality of larvae was carried out daily and the mortality of pupae and adults was observed. The experiment was conducted randomly in a 4 X 5 factorial scheme. The data was submitted to analysis of variance by F test, and the means compared by Tukey Test (p < 0.05). The concentrations of 100 ppm of the extract of A. coriacea showed residual effects with 100% mortality of larvae during the period of 15 days, and was not effective on the death of pupae and adults. Therefore, the residual effect presented by A. coriacea on A. aegypti can be used in future management programs for controlling the vector of dengue.