ABSTRACT Soil erosion is a serious environmental problem that can cause numerous types of damage to society and the environment, and thus require preventive measures. The objective of this study was to evaluate soil erosion vulnerability in the southern region of the Meia Ponte watershed, Goias, Brazil, considering two situations: natural and anthropic cover conditions. For the analysis, we used remote sensing data represented by several parameters: lithology, soil class, slope, rain intensity, vegetation index, vicinity of roads, and land use and occupation. For each variable, we established a scale of weights according to erosive susceptibility for natural and anthropogenic environments. Multicriteria analysis, which allows the combination of qualitative and quantitative information in the analysis of erosive susceptibility, was used through the relationship between soil use and land occupation. In the southern part of the Meia Ponte River watershed, the anthropic factor showed greater influence. The factors that increase erosive susceptibility were soil use and occupation, low vegetation index, and high slope. The southern part of the Meia Ponte watershed presents medium natural erosive susceptibility in most of the study area.

RESUMEN La erosión de los suelos es un grave problema ambiental que puede ocasionar numerosos daños a la sociedad y al medio ambiente, siendo necesario la adopción de medidas preventivas. Este estudio tuvo por objetivo evaluar la vulnerabilidad erosiva de los suelos en la región sur de la cuenca Meia Ponte, Goiás, considerando dos situaciones: condiciones de cobertura natural y antrópica. Para la realización de los análisis, se utilizaron datos de sensoriamiento remoto representados por diversos parámetros: litología, clase de suelo, declividad, intensidad de lluvia, índice de vegetación, cercanías de vías y uso y ocupación del suelo. Se establecieron para cada variable, una escala de pesos de acuerdo con susceptibilidad erosiva para el medio natural y otra antrópica. Se utilizó el análisis multicriterio, por medio de la relación entre las actividades de uso y ocupación del suelo, la cual permite combinar informaciones cualitativas y cuantitativas en análisis en cuanto a la susceptibilidad erosiva. En la parte sur de la cuenca del Río Meia Ponte, el factor antrópico obtuvo mayor influencia. Los factores que aumentaron susceptibilidad erosiva fueron el uso y ocupación del suelo, bajo índice de vegetación y la alta declividad. La parte sur de la cuenca Media Ponte, presenta susceptibilidad erosiva natural media en la mayor parte del área de estudio.

RESUMO Inseticidas à base de nim (Azadirachta indica A. Juss.) são eficientes para controle de várias espécies de pragas, porém o baixo efeito residual e a falta de padronização das formulações são um problema para uso em campo. Nanoformulações de nim em suspensão coloidal e em pó, contendo os polímeros poli-ε-caprolactona (PCL), poli-β-hidroxibutirato (PHB) e polimetilmetacrilato (PMMA) em cápsulas ou esferas, foram desenvolvidas, a fim de reduzir a biodegradação dos compostos ativos e melhorar seu efeito residual. Folhas de milho tratadas com as nanoformulações foram oferecidas a lagartas de primeiro ínstar de lagarta do cartucho durante 10 dias, observando-se a mortalidade e o peso larval e comparando com um óleo comercial de nim e controles negativos. O efeito residual das quatro nanoformulações mais eficientes foi avaliado aos 1, 3 e 7 dias, após a pulverização (DAP). Testes de preferência alimentar com dupla escolha (tratamento vs. controle) foram realizados com discos de folhas de milho aos 1, 3 e 7 DAP, e um índice de preferência foi determinado 24 horas após as lagartas se alimentarem nos discos foliares. Algumas nanoformulações causaram mortalidade até 3 DAP e efeitos subletais até 7 DAP, mas nenhuma superou o efeito residual do óleo comercial de nim. Todos os tratamentos apresentaram fagodeterrência em 1 DAP, mas esta foi perdida ao longo do tempo. A curta duração da eficiência das nanoformulações indica que houve pouca ou nenhuma liberação dos compostos das nanopartículas; assim, mais estudos são necessários para melhorar a cinética de liberação dos produtos nanoformulados.

ABSTRACT Neem (Azadirachta indica A. Juss.) based insecticides are efficient for the control of various pest species, but their low residual effect and the lack of standardized formulations are problems for field use. Nanoformulations of neem in colloidal suspension or powder, containing the polymers poly (ε-caprolactone) (PCL), poly (β-hidroxibutirate) (PHB) or poly (methyl methacrylate) (PMMA), in capsules or spheres, were developed in order to reduce biodegradation of the active neem compounds and improve their residual effect. Corn leaves treated with the nanoformulations were offered to first instar larvae of fall armyworm during 10 days, observing mortality and larval weight and comparing it to a commercial neem oil and negative controls. The residual effect of the four most efficient nanoformulations was evaluated at 1, 3 and 7 days after spraying (DAS). Feeding preference tests with dual-choice (treatment vs. control) were performed with corn leaf disks at 1, 3 and 7 after DAS, and a preference index was determined 24 hours after larvae feeding on the disks. Some nanoformulations caused mortality up to 3 DAS and sublethal effects up to 7 DAS, but none outperformed the residual effect of commercial neem oil. All treatments showed phagodeterrence at 1 DAS, but this was lost over time. The short duration of the nanoformulations' efficacy suggests that there was little or no release of neem by the nanoparticles, so more studies are needed to improve the release kinetics of the nanoformulated products.

e evaluó el efecto de fracciones de hexano, diclorometano, acetato de etilo e hidroalcohólica, obtenidas a partir del extracto de etanol de Trichilia pallida, Trichilia pallens y Toona ciliata sobre el crecimiento y fisiología nutricional de Spodoptera frugiperda. Larvas de primer estadio se alimentaron con dieta tratada con dichas fracciones durante diez días. Las fracciones más activas fueron aplicadas sobre la dieta y se ofrecieron a las larvas hasta pupa para verificar efectos sobre el crecimiento y sobrevivencia. Para calcular los índices nutricionales, la dieta con las fracciones fueron ofrecidas a las larvas de cuarto estadio durante cuatro días. La fracción de diclorometano de ramas de T. pallens afectó el crecimiento y la sobrevivencia de las larvas. Por otra parte, las fracciones de diclorometano de ramas y hojas de T. pallida y hojas y frutos de To. ciliata afectaron el crecimiento larval. El análisis nutricional indicó que la fracción de hojas de To. ciliata actúa principalmente como disuasor de alimentación mientras que las fracciones de diclorometano de ramas y hojas de T. pallens, frutas de To. ciliata y ramas de T. pallens causan efectos tóxicos después de la ingestión, reduciendo la eficiencia de conversión de alimento y aumentando el costo metabólico para las larvas.

The effect of hexane, dichloromethane, ethyl acetate and hydroalcoholic fractions obtained from ethanolic extract of Trichilia pallida, T. pallens and Toona ciliata on growth and nutritional physiology of Spodoptera frugiperda was evaluated. First instar larvae were fed on a diet treated with fractions for ten days. The most active fractions were applied on the diet and offered to larvae until the pupal stage to verify effects on growth and survival. To calcúlate the nutritional indices, fractions were incorporated into the diet offered to fourth instar larvae for four days. The dichloromethane fraction of T. pallens stems affected growth and survival of S. frugiperda larvae, and fractions of T. pallida leaves and stems, and of To. ciliata leaves and fruits affected larval growth. Nutritional analysis indicated that the fraction of To. ciliata leaves acts mainly as a phagodeterrent, while dichlorometane fractions of T. pallida stems and leaves, To. ciliata fruits and T. pallens stems cause toxic effects after ingestion, reducing the efficiency of food conversion and increasing the metabolic cost to the larvae.