O objetivo deste trabalho foi avaliar os efeitos do clorpirifós sobre as minhocas e sobre parâmetros funcionais do solo. Foi executado um estudo integrado campo-laboratório, em uma plantação de trigo na Argentina, onde foi aplicado clorpirifós em duas doses recomendadas (240 ou 960 g ha-1 a.i.). Os ensaios laboratoriais incluíram tempo de retenção do vermelho-neutro, ensaio cometa (eletroforese em gel de célula única) e teste de fuga, cada um com a minhoca Eisenia andrei exposta aos solos coletados 1 e 14 dias após tratamentos, e teste com a lâmina-isca. Nos bioensaios de campo, avaliou-se a decomposição da matéria orgânica em sacolas com alfafa e com a lâmina-isca. As populações de minhocas foram avaliadas no campo com uso do método de extração com formalina e remoção manual. O tempo de retenção do vermelho-neutro e o ensaio cometa foram biomarcadores sensíveis aos efeitos do clorpirifós na minhoca E. andrei; porém, o comportamento de fuga não foi eficiente para avaliar tais efeitos. A atividade alimentar da biota do solo, avaliada pelo teste de lâmina-isca, foi significativamente inibida pelo clorpirifós após 97 dias, mas recuperou-se no 118º dia do teste. O teste de sacolas com alfafa não mostrou diferenças significativas em comparação aos controles. A abundância das minhocas em campo foi muito baixa, para testar adequadamente a sensibilidade desta variável.

The objective of this work was to evaluate the effects of chlorpyrifos on earthworms and on soil functional parameters. An integrated laboratory-field study was performed in a wheat field in Argentina, sprayed with chlorpyrifos at two recommended application rates (240 or 960 g ha-1 style='vertical-align:baseline'> a.i.). Laboratory tests included neutral red retention time, comet assay (single cell gel electrophoresis), and avoidance behavior, each using the earthworm Eisenia andrei exposed in soil collected 1 or 14 days after pesticide application, and the bait-lamina test. Field tests assessed organic matter breakdown using the litterbag and bait-lamina assays. Earthworm populations in the field were assessed using formalin application and hand-sorting. The neutral red retention time and comet assays were sensitive biomarkers to the effects of chlorpyrifos on the earthworm E. andrei; however, the earthworm avoidance test was not sufficiently robust to assess these effects. Feeding activity of soil biota, assessed by the bait lamina test, was significantly inhibited by chlorpyrifos after 97 days, but recovered by the 118th day of the test. Litterbag test showed no significant differences in comparison to controls. Earthworm abundance in the field was too low to adequately test the sensitivity of this assessment endpoint.

The incidence of Tuta absoluta in tomato production, the use of pesticides for its control, the risk of contamination to the environment and the creation of a generation of resistance, makes it very important to find alternative ways to efficiently control the tomato borer. This test was developed under greenhouse conditions to assess the effectiveness of the imidacloprid to the control of this pest at different rates and application forms. Two dilutions of the insecticide were prepared and applied in two different ways: by watering and by the immersion of the root of the plants into the soil bed. To evaluate the damage, calculations were carried out on the percentage of the leaves damaged on each plant and on the number of lesions on each leaf at different moments of the application. The design was factorial, completely randomized and with 9 replications, and an ANOVA was carried out. Significant differences were confirmed among the dilutions and also among the two application forms (watering and immersion). The better treatments were: dilution of 3,5% applied by watering and dilution of 7% applied by immersion.

La grave incidencia de Tuta absoluta en la producción de tomate, el alto uso de plaguicidas para su control, el riesgo de contaminación del ambiente y la generación de resistencia hacen que sea muy importante encontrar formas alternativas de control eficiente de esta plaga. Con el fin de evaluar la eficacia del imidacloprid en el control de la polilla del tomate, en distintas dosis y formas de aplicación se desarrolló este ensayo en condiciones de invernáculo. Para ello se prepararon dos diluciones del insecticida, que fueron aplicadas de dos formas: por riego y por inmersión de la raíz del plantín con su pan de tierra. Para evaluar el daño se realizó el cálculo del porcentaje de folíolos dañados por planta y el número de lesiones por hoja en distintos momentos desde la aplicación. El diseño fue factorial, completamente aleatorizado y con nueve repeticiones, aplicándose ANOVA. Se comprobó que hay diferencias significativas entre las diluciones y también entre las dos formas de aplicación (riego e inmersión). Siendo los tratamientos que mejor controlaron a la plaga: dilución al 3,5% aplicada por riego y dilución al 7% aplicada por inmersión.

O cerne da madeira de Caesalpinia echinata Lam. (pau-brasil, Pernambuco, ibirapitanga) é considerado o material mais adequado para a construção de arcos de violinos devido às suas propriedades vibracionais e a estabilidade. Embora a madeira dessa leguminosa seja resistente à deterioração causada por fungos apodrecedores e cupins, um bosque experimental de pau-brasil no Sudeste do Brasil vem sendo atacado pelo besouro de ambrosia Platypus mutatus Chapuis (= Megaplatypus mutatus e P. sulcatus). Esse coleóptero invadiu cerca de 3% das árvores, principalmente na região central do bosque. A infestação por larvas e insetos adultos foi maior durante a estação seca (inverno) quando comparada ao período chuvoso (primavera e verão).

The hardwood of Caesalpinia echinata Lam. (brazilwood, Pernambuco, ibirapitanga) is currently the most profitable material used for violin bow due to the unique vibrational properties and dimensional stability. Although this species is resistant to the wood decay caused by termites and rot fungi, an experimental plantation in Southeastern Brazil has been attacked by the ambrosia beetle Platypus mutatus Chapuis (= Megaplatypus mutatus and P. sulcatus). This species invaded ca. 3% of the individuals, mainly in the central part of the plantation. Infestation by larvae and adults was higher during the dry season (winter) when compared to the rainy period (spring and summer).

Soil organisms have an essential role in the processes of humification, de composing and structuring consequently several toxicological studies have been carried out to determine the impact of insecticides on them, principally in laboratory with individual species. Regretably, there are few field assays. The objective of this research was to determine the effect caused by the insecticide imidacloprid on soil organisms when it was applied to peach trees (Prunus persica (L.) Batsch) var. Red Globe. The control treatment (without chemicals) managed with yellow and pheromone traps was compared with treated plots in which the insecticide was applied to the soil and leaves, using two different concentrations for each treatment (0.5 and 10 cm³ L-1). A litter bag assay was carried out in order to determine the impact of the insecticide. Polyethylene bags with two different mesh sizes full of dry alfalfa (Medicago sativa L.) were buried. The distinct mesh sizes permitted the entrance of different organisms, achieving a stratification of the acting species. At five months, the bags were removed and the dry matter weight was analyzed. The experimental design was a split plot and the combination of factors produced eighteen treatments with three replicates. The results were analyzed using ANOVA. There were no significant differences between soil and canopy treatments and control (6, 5.92 and 5.83 g DM, respectively), nor between concentrations. The decomposition of organic matter was greater (p < 0.05) in the buried bags with bigger mesh size (6.38 g DM) than the smaller mesh size (5.45 g DM) probably due to a greater activity of the soil macrofauna.

Los organismos del suelo cumplen un rol esencial en los procesos de humificación, descomposición y estructuración; consecuentemente se han realizado numerosos estudios toxicológicos sobre el impacto de los insecticidas sobre ellos, principalmente en condiciones de laboratorio y con especies individuales. Lamentablemente, existen pocos ensayos de campo. El objetivo de esta investigación fue determinar el efecto de imidacloprid en durazneros (Prunus persica (L.) Batsch) var. Red Globe sobre los organismos del suelo. Se compararon parcelas testigo (sin tratamiento químico) manejadas con trampas amarillas y de feromonas, con parcelas tratadas con aplicaciones al suelo y foliares, con dos concentraciones para cada tratamiento (0,5 y 10 cm³ L-1). Para evaluar el impacto del insecticida se realizó un ensayo de bolsas de residuos. Se enterraron bolsas de nylon con perforaciones de dos tamaños, llenas con heno de alfalfa (Medicago sativa L.). Los distintos tamaños de malla permitieron el paso de diferentes organismos, logrando una estratificación de las especies actuantes. A los cinco meses se retiraron las bolsas y se analizó su peso seco. El diseño experimental fue en subparcelas divididas y la combinación de factores dio origen a 18 tratamientos con tres repeticiones. Los resultados se analizaron por ANDEVA. No hubo diferencias significativas entre los tratamientos de pulverización foliar, riego y testigo (6; 5,92; y 5,83 g MS, respectivamente), como tampoco entre las concentraciones. La descomposición de la materia seca fue mayor (p < 0,05) en las bolsas de malla grande (6,38 g MS) que en las de malla chica (5,45 g) probablemente como consecuencia de una mayor actividad de la macrofauna edáfica

In order to evaluate the ecotoxicity of chlorpyrifos and tefluthrin on the earthworm Lumbricus terrestris L., a laboratory test was carried out based on the guidelines of the International Organization of Biological Control (IOBC). The earthworms were collected by handsorting from a soil free of pesticides of the Agronomy Faculty, University of Buenos Aires, Argentina and placed in sterilized soil, in complete darkness, at 12ºC for five days, and fed with dry white clover (Trifolium repens L.) leaves. Earthworms larger than 1.5 g without clitelum were placed in a Daniel's funnel with ten dry leaves of white clover on the surface. The treatments were: 1) control, unchlorinated water; 2) chloroacetamid solution (97.37%) 30 mg L-1; 3) chlorpyrifos (emulsifiable concentrate, EC, 48%) 5 L ha-1 or 50 mg L-1; 4) tefluthrin (EC 5%) 2 L ha-1 or 20 mg L-1. A completely randomized experimental design with ten replicates was used. During 15 days of the assay the variables analyzed were: live weight change, individual activity and earthworm survival. The increase of earthworm weight was 0.285, 0.280 and 0.300 g in the 15 days of treatments 1, 3 and 4, respectively, with no significant differences between treatments, as well as the number of leaves withdrawn per day 0.61, 0.369, 0.555, and 0.425, respectively. The survival rates were: 100, 20, 100 and 90%, in treatments 1, 2, 3 and 4, respectively, being only effected by chloroacetamid. Chlorpyrifos and tefluthrin were not toxic for L. terrestris at the current dose (P < 0.05).

Para evaluar la ecotoxicidad de clorpirifos y teflutrina sobre Lumbricus terrestris L., se realizó una prueba de laboratorio, basado en el protocolo de la Organización Internacional de Control Biológico (IOBC). Las lombrices fueron recolectadas a mano en un suelo libre de plaguicidas, en el campo de la Facultad de Agronomía, Universidad de Buenos Aires, Argentina y colocadas en suelo esterilizado, en condiciones de oscuridad y 12°C durante cinco días, alimentadas con hojas secas de trébol blanco (Trifolium repens L.). Se colocó una lombriz mayor a 1,5 g sin clitelo por embudo de Daniel, con diez hojas secas de trébol blanco sobre la superficie. Los tratamientos fueron: 1) testigo, agua no clorada; 2) 30 mg L-1 de solución de cloroacetamida (97,37%); 3) clorpirifos (EC 48%) 5 L ha-1 o 50 mg L-1; 4) teflutrina (EC 5%) 2 L ha-1 o 20 mg L-1. El ensayo tuvo diseño completamente aleatorizado con diez repeticiones. Durante los 15 días de ensayo las variables analizadas fueron: variación de peso, actividad individual y supervivencia de lombrices. El incremento de peso de las lombrices fue 0,285; 0,280 y 0,300 g en 15 días en los tratamientos 1, 3 y 4 respectivamente, y no hubo diferencias significativas entre los mismos así como en la cantidad de hojas retiradas al día, que fue de 0,61; 0,369; 0,555 y 0,425, respectivamente. La supervivencia fue de 100; 20; 100; y 90% en los tratamientos 1, 2, 3 y 4, respectivamente, siendo afectada sólo por cloroacetamida. Clorpirifos y teflutrina no fueron tóxicos a las dosis evaluadas (P < 0,5).