RESUMEN El uso de aceites vegetales como insecticida es una de las alternativas ecológicas a los insecticidas químicos sintéticos. Con la finalidad de evaluar la efectividad de los aceites vegetales en el control de la mosca negra de los cítricos, la presente investigación se realizó en el Laboratorio de Biología y en el campo experimental de la Facultad de Ciencias Agrarias de la Universidad Nacional de Asunción. Fueron llevados a cabo dos ensayos; uno a campo y otro en laboratorio, en ambos casos se utilizaron un diseño completamente al azar con ocho tratamientos y tres repeticiones, los resultados fueron sometidos a un análisis de varianza, seguido de un test de comparación de medias por Tukey al 5% de probabilidad. Los tratamientos fueron: testigo (sin aplicación), suspensiones al 2% de aceite mineral, aceite de girasol nuevo, detergente, aceite de girasol reciclado, aceite de canola, aceite de maíz, aceite de soja y aceite de algodón, se realizaron en total dos aplicaciones para el ensayo a campo y una aplicación para el ensayo en laboratorio. Se evaluó la mortalidad en un periodo de siete días para el ensayo en laboratorio y de 14 días para el ensayo a campo, de ninfas Aleurocanthus woglumi Ashby luego de la aplicación de los tratamientos. La efectividad en el control de la mosca negra de los cítricos se observó para cada uno de los aceites vegetales evaluados en ambos ensayos, alcanzando una mortalidad de hasta 100% en las dos aplicaciones. Todos los aceites utilizados resultaron en tasas de mortalidad superior al 90%, luego de la segunda aplicación, siendo evidente que, el control de la mosca negra de los cítricos puede ser realizado mediante el uso de aceites vegetales; producto alternativo a los químicos sintéticos.

ABSTRACT The use of vegetable oils as an insecticide is one of the ecological alternatives to synthetic chemical insecticides. In order to evaluate the effectiveness of vegetable oils in the control of the citrus black fly, this research was carried out in the Biology Laboratory and in the experimental field of the Faculty of Agricultural Sciences of the National University of Asunción. Two trials were carried out; one in the field and the other in the laboratory, in both cases a completely randomized design with eight treatments and three repetitions was used, the results were subjected to an analysis of variance, followed by a comparison test of means by Tuckey at 5% probability The treatments were: control (without application), suspensions at 2% of mineral oil, new sunflower oil, detergent, recycled sunflower oil, canola oil, corn oil, soybean oil and cottonseed oil, were carried out in total two applications for the field test and one application for the laboratory test. Mortality was evaluated in a period of seven days for the laboratory test and 14 days for the field test, of Aleurocanthus woglumi Ashby nymphs after the application of the treatments. The effectiveness in the control of the citrus black fly was observed for each of the vegetable oils evaluated in both trials, reaching a mortality of up to 100% in the two applications. All the oils used resulted in mortality rates higher than 90%, after the second application, being evident that the control of the citrus black fly can be carried out through the use of vegetable oils; alternative product to synthetic chemicals.

ABSTRACT The larvae of the Order Lepidoptera are important pests that cause significant damage to horticultural crops. Biological control by parasitoids is a potential alternative for their management. In order to know the niche of larvae parasitoids of the Order Lepidoptera in broccoli, cabbage, tomato and zucchini crops of conventional management of the Fruit-horticultural Center of the Faculty of Agricultural Sciences (FCA) of the National University of Asunción (UNA), larvae of the Order Lepidoptera were collected in said cultures. Ten genera of parasitoids were identified, which were Apanteles sp. (Hymenoptera: Braconidae), Carcelia sp. (Diptera: Tachinidae), Charops sp. (Hymenoptera: Ichneumonidae), Chelonus sp. (Hymenoptera: Braconidae), Copidosoma sp. (Hymenoptera: Encyrtidae), Euplectrus sp. (Hymenoptera: Eulophidae), Glyptapanteles spp. (Hymenoptera: Braconidae), Oomyzus sokolowskii (Hymenoptera: Eulophidae), Parapanteles sp. (Hymenoptera: Braconidae), and Pseudapanteles sp. (Hymenoptera: Braconidae). Parasitism of Carcelia sp. and Charops sp. in larvae of Diaphania hyalinata (Lepidoptera: Crambidae). The parasitoids Copidosoma sp. were responsible for the highest percentage of parasitism (57.29%), followed by Pseudapanteles sp. (48.48%) and Chelonus sp. (29.41%).

RESUMEN Las larvas del Orden Lepidoptera son plagas importantes que causan daños significativos en los cultivos hortícolas. El control biológico por los parasitoides es una alternativa potencial para el manejo de estas. Con la finalidad de conocer el nicho de parasitoides de larvas del Orden Lepidoptera en los cultivos de brócoli, repollo, tomate y zapallito de tronco de manejo convencional del Centro Fruti-hortícola de la Facultad de Ciencias Agrarias (FCA) de la Universidad Nacional de Asunción (UNA), se recolectaron larvas del Orden Lepidoptera en dichos cultivos. Se identificaron diez géneros de parasitoides, los cuales, fueron Apanteles sp. (Hymenoptera: Braconidae), Carcelia sp. (Diptera: Tachinidae), Charops sp. (Hymenoptera: Ichneumonidae), Chelonus sp. (Hymenoptera: Braconidae), Copidosoma sp. (Hymenoptera: Encyrtidae), Euplectrus sp. (Hymenoptera: Eulophidae), Glyptapanteles spp. (Hymenoptera: Braconidae), Oomyzus sokolowskii (Hymenoptera: Eulophidae), Parapanteles sp. (Hymenoptera: Braconidae), y Pseudapanteles sp. (Hymenoptera: Braconidae). Se reportó por primera vez el parasitismo de Carcelia sp. y Charops sp. en larvas de Diaphania hyalinata (Lepidoptera: Crambidae). Los parasitoides Copidosoma sp. fueron los responsables de mayor porcentaje de parasitismo (57,29%), seguido por Pseudapanteles sp. (48,48%) y Chelonus sp. (29,41%). La identificación de estos parasitoides es un aporte para el conocimiento de la fauna benéfica del país.

ABSTRACT Estimates of diversity indices provide information on distribution, richness and abundance of species within a community. The aim of the current study was to estimate faunistic indices (richness, constancy, dominance and abundance) of the species collected by beat cloth and entomological net sampling methods in different soybean crops and to determine the sample size necessary to estimate faunistic indices. Fauna density from 100 soybeans crops located in nine municipalities in Rio Grande do Sul, Brazil, were evaluated. Thirty points, 20 meters apart from one another, were marked in the crops. At each point, insect pests and natural enemies were collected using the two sampling methods. Faunistic indices, including the average and interval estimates carried out by the resampling method, were calculated for each soybean crop. In the samplings using the beat cloth, richness > dominance = abundance > constancy, and using the entomological nets, richness > dominance > abundance > constancy. All faunistic indices other than dominance were greater when using the beat cloth method than those estimated by the entomological net method. The sample sizes required to estimate richness, constancy, dominance and abundance indices were 38, 78, 47 and more than 300, respectively, with an estimation error of 20 % of the average (p = 0.05). Higher values were observed when entomological net was used.

ABSTRACT Sampling is one of the basis for decision-making to control pests in soybean crops. Thus, to determine the most appropriate sampling plan is to define the sampling unit, the sampling method and sample size for the quantification of insect population. The objective of the study was to estimate the sample size to measure caterpillar species population density, with varying methods of collection, of altitude and of soybean cultivars. Samples were taken from 100 soybean fields, located in nine districts in the central region of Rio Grande do Sul, during three growing seasons (2010/2011, 2011/2012, 2012/2013). In each field, 30 points separated by 20 meters each were marked off. At each point caterpillars of the species Chrysodeixis includens, Anticarsia gemmatalis and Rachiplusia nu were collected through the wide-beating cloth-methods and entomological network, totaling 6,000 units. The sample size (number of points) to determine the density of tracks varies with the method of collection and population density. Using the wide-beating cloth method for soybean caterpillars collection for an estimation error (confidence interval amplitude) equal to two caterpillars and population density in the class> 2 caterpillars. m-2, the sample size is 47, 78 and 18, respectively, for the C. includens, A. gemmatalis and Rachiplusia nu species, as for the entomological network method, sample sizes are 19 and 43 for the C. includens e A. gemmatalis species. The study shows that sample size (number of points) to determine caterpillars population density varies according to, collection method, altitude, soybean cultivars and population density.

RESUMO A amostragem de pragas é uma das bases para a toma de decisão no manejo de pragas em lavouras de soja. Assim, determinar o plano amostral mais adequado consiste em definir a unidade amostral, o método de amostragem e o tamanho de amostra para a quantificação da entomofauna. O objetivo foi estimar o tamanho de amostra para medir a densidade populacional de espécies de lagartas, variando métodos de coleta, altitude e cultivares de soja. Foram amostradas 100 lavouras de soja, distribuídas em nove municípios da região central do Rio Grande do Sul, em três safras agrícolas (2010/2011, 2011/2012, 2012/2013). Em cada lavoura foram demarcados 30 pontos distanciados 20 metros entre si. Em cada ponto foram coletadas lagartas das espécies Chrysodeixis includens, Anticarsia gemmatalis e Rachiplusia nu, por meio dos métodos pano-de-batida largo e rede entomológica, totalizando 6.000 coletas. Para cada lavoura, método de coleta e espécie de lagarta foi estimado a média da densidade populacional e o tamanho de amostra por meio de reamostragem. Usando o pano-de-batida largo para a coleta de lagartas em soja, para um erro de estimação (amplitude do intervalo de confiança) igual a dois lagartas e densidade populacional na classe > 2 lagartas. m-2, o tamanho de amostra é 47, 78 e 18, respectivamente, para as espécies C. includens, A. gemmatalis e R. nu e para rede o tamanho de amostra é 19 e 43, respectivamente, para as espécies C. includens e A. gemmatalis. Os resultados indicam que o tamanho de amostra (número de pontos) para determinar a densidade populacional de lagartas varia com o método de coleta, altitude, cultivar e a densidade populacional.

RESUMO: O objetivo deste trabalho foi estimar o tamanho de amostra para medir a densidade populacional de espécies de percevejos, variando métodos de coleta, altitude e cultivares de soja. Foram utilizadas 100 lavouras de soja, distribuídas em nove municípios da região central do Rio Grande do Sul, em três safras agrícolas (2010/2011, 2011/2012, 2012/2013). Em cada lavoura, foram demarcados 30 pontos distantes em 20 metros entre si. Em cada ponto, foram coletados percevejos (adultos + ninfas) das espécies Dichelops sp., Piezodorus guildinii e Euchistus heros, por meio dos métodos pano-de-batida largo e rede entomológica, totalizando 6.000 coletas. Para cada lavoura, método de coleta e espéciede percevejo, foram estimadas a média da densidade populacional e o tamanho de amostra por meio de reamostragem. O tamanho de amostra (número de pontos) para determinar a densidade populacional de percevejos varia com o método de coleta e a densidade populacional. Usando o pano-de-batida largo para a coleta de percevejos em soja, para um erro de estimação (amplitude do intervalo de credibilidade) igual a dois percevejos e densidade populacional na classe de 1,5 a 2,0 percevejos m-2, o tamanho de amostra é 13, 77 e 15, respectivamente, para as espécies Dichelops sp., P. guildinii e E. heros.

ABSTRACT: The objective was to estimate the sample size to evaluate the population density of bugs species, varying collection methods, altitude and soybean cultivars. There were used 100 soybean fields, distributed in nine districts of the central region of Rio Grande do Sul on three growing seasons (2010/2011, 2011/2012, 2012/2013). In each field, 30 equidistant points were marked at 20 meters. Bugs (adults and nymphs) of Dichelops sp., Piezodorus guildinii and Euchistus heros species were collected at each point using beat cloth and sweep net, totaling 6,000 collections. For each field, collection method and bug speciesit was estimated average population density, and sample size by resampling. The sample size (number of points) to estimate the population density of bugs vary with the species, altitude, soybean cultivar and the collection method. Using the beat cloth method to collect bugs in soybean, for an estimate error equal to two bugs and population density at class of 1.5 to 2.0 bugs m-2, the number of sampling points are 13, 77 and 15, respectively, for Dichelops sp., P. guildinii and E. heros.

To obtain high productivity in sugar cane, all available technologies and tactics seeking to improve product quality in harmony with the environment should be applied. The objective of this work was to evaluate two sugarcane varieties and to determine its response to nitrogen rates and their effect on sugar cane borer attack, in field conditions. The experiment was carried out at the research field area of Federal University of Santa Maria, RS, Brazil. A two factorial experiment containing two sugarcane varieties (RB-956911 and SP81-3250), and four N rates (0, 40, 80 and 120 kg N ha-1). We assessed a) sugarcane stalk length, b) stem base diameter; c) number of internodes, d) number of stalk ha-1, e) stalk yield, f) °Brix g) Intensity of Infestation (II), and h) Intensity of infestation Index (III). Results indicated that the stalk yields of RB-956911 and SP81-3250 was 111,730 and 126,752 Mg ha-1, respectively. The °Brix was between 18.60 and 18.15, respectively. The II and III was not affected by variety, with II between entre 3.96% y 2.88% and III between 4,62% y 3.03%, respectively for sugarcane variety RB-956911 and SP81-3250. Nitrogen fertilization increases stalk yield, decrease °Brix, and does not affect sugarcane borer attack.

Para la obtención de alta productividad en caña de azúcar se deben aplicar tecnologías y técnicas que mejoren la calidad del producto en armonía con el ambiente, por ello el objetivo del trabajo fue evaluar el efecto de un fertilizante nitrogenado sobre la producción de dos cultivares de caña de azúcar y el ataque del taladrador, en condiciones de campo. Se realizó en el área experimental del Departamento de Suelos de la Universidad Federal de Santa María, RS, Brasil. El diseño experimental fue bi factorial, siendo el primer factor dos cultivares (RB-956911 y SP81-3250) y, el segundo factor la aplicación de cuatro dosis de nitrógeno (0, 40, 80 y 120 kg ha-1). Se evaluó: a) longitud de la parte industrial (LPI), b) diámetro de la base del tallo, c) el número de entrenudos, d) número de tallos ha-1, e) rendimiento, f) Grados (°) Brix, g) Intensidad de Infestación (II) y h) Índice de Intensidad de Infestación (III). El rendimiento de los cultivares RB-956911 y SP81-3250 fue de 111.730 y 126.752 Mg ha-1, respectivamente, el °Brix de 18,60% y 18,15%, respectivamente. La II y el III no fueron afectados por el cultivar, presentando valores de II entre 3,96% y 2,88% y de III entre 4,62% y 3,03%, respectivamente para el cultivar RB-956911 y SP81-3250. La aplicación de nitrógeno aumenta la producción de caña de azúcar, disminuye el °Brix y no influencia en el ataque del taladrador de la caña de azúcar.