Effect of thiamethoxam (organophosphate) on the flies and beetle visitation and cadaveric decomposition process

ABSTRACT Entomofauna associated with decaying cadavers may be useful in criminal investigation, either through the development of immature insects of interest or through entomological succession in corpses. These factors may vary if the insects are exposed to toxic substances that can modify the insect's developmental cycle, as well as its own occurrence, which would imply significant changes in the results of any investigation. However, there are few studies on how contamination by toxic compounds can affect the action of insects on carcasses and their consequence for forensic expertise. Therefore, this study aimed to test the hypothesis that the normal visitation of flies and beetles is altered in insecticide-contaminated carcasses. The experiment was carried out in a sugarcane plantation, using pig carcasses contaminated with insecticide and the same number of carcasses without any type of contamination as a control. In all experiments, the contaminated carcasses reached the final phase of decomposition in a longer time than the uncontaminated carcasses of the control group. A total of 2.767 specimens were collected and identified, 2.103 individuals from the order Diptera and 664 from the order Coleoptera. There was a significant geometric regression adjustment during the decomposition phases only for the control group, different from the contaminated carcasses in which this pattern did not occur. Results show that contamination by insecticide alters decomposition time and phase, altering the action of flies and beetles, affecting the abundance, composition of species as well as their activities, which can alter the data used by experts in criminal experts.

Contenidos de carbono y nitrógeno del suelo en un agroecosistema altoandino del Valle del Cauca, Colombia

Los ecosistemas altoandinos o de alta-montaña, se caracterizan por prestar servicios ecosistémicos esenciales, muchos de ellos, relacionados con el suelo; sin embargo, se conoce que las actividades agrícolas y pecuarias han llevado a cambios progresivos en los parámetros físicos, químicos y agotamiento del carbono orgánico y nitrógeno del suelo, contribuyendo a la pérdida de calidad edáfica e incrementando las emisiones de gases de efecto invernadero. Este estudio evaluó la influencia de tres coberturas vegetales: bosque nativo, pastizal naturalizado de Pennisetum clandestinum y monocultivo de Allium fistulosum, sobre algunas propiedades del suelo, en un ecosistema altoandino del Valle del Cauca (Colombia). Se midieron propiedades edáficas, como densidad aparente, materia orgánica, contenidos y almacenamiento de C y N. Se encontró que las prácticas agrícolas asociadas al monocultivo influyeron significativamente en las propiedades edáficas evaluadas, generando cambios a nivel físico y químico, lo que podría aumentar la vulnerabilidad del suelo a la degradación. Se observó que los pastizales de P. clandestinus (C4), con un manejo del pastoreo de tipo extensivo, baja carga animal, presentaron mayor potencial para acumular C, reciclar N y mitigar el efecto del pisoteo, siempre y cuando, se garantice una gestión óptima del pastoreo, en términos de una carga animal, ambientalmente sostenible. El tipo de cobertura vegetal y las prácticas de manejo asociadas promovieron cambios físicos y químicos, en los primeros centímetros del suelo, afectando la capacidad del suelo para almacenar C y N, lo que podría incidir en la provisión de Servicios Ecosistémicos.

High Andean or high-mountain ecosystems are characterized by providing essential ecosystem services, many of them related to the soil. However, it is known that agricultural and livestock activities have led to progressive changes in the physical and chemical parameters of the soil and depletion of organic carbon and nitrogen, contributing to the loss of edaphic quality and increasing greenhouse gas emissions. This study evaluated the influence of three kinds of plant covers: native forest, Pennisetum clandestinum naturalized grassland, and Allium fistulosum monoculture, on some soil properties in a high Andean ecosystem of Valle del Cauca (Colombia). The edaphic properties measured were: bulk density, soil organic matter, C and N contents, and storage. It was found that the agricultural practices associated with monoculture significantly influenced the evaluated edaphic properties, generating changes at a physical and chemical level, which could increase the vulnerability of the soil to degradation. It was observed that the grasslands of P. clandestinus (C4), with extensive grazing management, and a low stocking rate, presented the greater potential to accumulate C, recycle N and mitigate the trampling effect, as long as optimal management is guaranteed in terms of environmentally sustainable stocking load. The kind of vegetation cover and the associated management practices, promoted physical and chemical changes, in the first centimeters of the soil, affecting the soil's capacity to store C and N, which could affect the provision of Ecosystem Services.

Minadores de hojas del aguacate (Lepidoptera: Gracillariidae). Estado actual, Identificación, evaluación de daño y propuesta de manejo / Leaf miners of avocado (Lepidoptera: Gracillariidae). Status, identification, damage evaluation and management proposal

RESUMEN El cultivo de aguacate representa uno de los principales productos agrícolas de Colombia. Durante las últimas dos décadas, el área sembrada se quintuplicó y se ampliaron, notablemente, las zonas de siembra, en especial, para el cultivar Hass. Con el crecimiento de su producción, también se reportan nuevos problemas fitosanitarios, mayormente, por la adopción de sistemas productivos de otras latitudes del mundo, donde no se cuentan con ecosistemas con presencia de lauráceas y otras plantas relacionadas con el aguacate. Dentro de las especies plagas, se registra a los minadores de hojas del orden Lepidoptera, que se caracterizan por desarrollarse y alimentarse dentro de las hojas, cuyo efecto perjudicial, se genera, en principio, cuando son afectadas las poblaciones de sus enemigos naturales. El primer registro documentado de estos insectos en el país, se realizó a partir de muestras colectadas en un cultivo de aguacate cv. Hass, en Villamaría, (Caldas), que presentó una explosión de las poblaciones de minadores, como consecuencia de la aplicación calendario de plaguicidas, con el criterio de proteger de plagas al cultivo, como arañita roja y trips. Con el fin de evitar que se aumente la frecuencia de eventos, como el enunciado, se desarrolló el trabajo actual, el cual, tuvo como objeto presentar el estado actual de los minadores de hoja del aguacate en Colombia, identificación y descripción del daño del minador de hojas del aguacate en serpentina y en ampolla y brindar recomendaciones para su manejo, en las zonas productoras de Colombia.

ABSTRACT Avocado has become one of the most important crops in Colombia. During the last two decades, the area planted with avocado has quintuplicated, and it is widespread across a wide range of high-altitude lands growing in monoculture with Hass variety. As the plantation areas increase, new sanitary problems appear, as consequences of the adoption of technical recommendations from other latitudes where the ecosystems do not have laurels and other plants related to avocado. Within the pest species, the leafminers of Lepidoptera are reported, which the main characteristic is that they develop and feed inside the leaves. The damage they cause happens mainly when the population of their natural enemies is affected. The first record of leafminers in Colombia was done from samples collected in one orchard of avocado cv. Hass in Villa Maria, Caldas where a high infestation outbreak happened as a consequence of the pesticide application following calendar spraying to prevent the attack of pests like red spider mites and thrips. The objective of this paper is to present the status of leafminer pest of avocado leaves in Colombia, providing its identification, description of the serpentine and blotch damage, and proposing recommendations for its management. This will inform the scientific community and farmers about the presence of this pest in avocado crop regions in Colombia, contributing to minimize damaging events like the aforementioned.

Propiedades de algunos suelos cultivados con cacao en la provincia El Oro, Ecuador / Properties of several soils cultivated with cocoa in the province of El Oro, Ecuador

Resumen Las propiedades físicas y químicas del suelo, en conjunto, condicionan la capacidad productiva de las plantas. La investigación tuvo como objetivo caracterizar las propiedades de los principales suelos cacaoteros de la provincia de El Oro (Ecuador), en los municipios de El Guabo, Machala, Santa Rosa y Pasaje. Se seleccionaron 30 parcelas, conformadas por los tipos de cacao CCN51 (n = 18) y Nacional (n = 12), de las cuales, se extrajeron muestras de suelo de 0 cm a 30 cm, para analizar varias propiedades físicas y químicas en laboratorio. Los resultados no mostraron diferencias significativas (P > 0.05) entre las propiedades físicas. Los niveles de carbono variaron de 1.58 % (El Guabo) a 2.06 % (Santa Rosa). En general, el nitrógeno fue bajo (0.16 % a 0.18 %). Los valores de CE (rango; 0.13 dS/m a 0.21 dS/m), pH (rango, 6.46 a 7.72), CIC (23.40 cmol/kg a 43.86 cmol/kg), potasio (0.31 cmol/kg a 1.86 cmol/kg) y calcio (19.99 cmol/kg a 37.73 cmol/kg), tendieron a ser más altos en suelos de Machala (P < 0.05) y más bajos en los de Pasaje. En Santa Rosa, los suelos presentaron concentraciones más altas de cobre (16.6 mg/k) (P < 0.05), que en el resto de los municipios. El rendimiento del cacao CCN51 (2 570.24 kg/ha/a a 4 158.34 kg/ha/a) fue superior a Nacional (324.00 kg/ha/a a 814.17 kg/ha/a). Los suelos de Machala presentaron valores nutrimentales más altos, asociados con el mayor rendimiento promedio para cacao variedad Nacional, y un alto rendimiento para variedad CCN51.

Abstract The physical and chemical properties of the soil, as a whole, condition the productive capacity of the plants. The research aimed to characterize the properties of the main cocoa soils in the province of El Oro (Ecuador), in the municipalities of El Guabo, Machala, Santa Rosa and Pasaje. We selected 30 plots of cocoa types CCN51 (n = 18) and National (n = 12), from which soil samples from 0 cm to 30 cm were extracted to analyze various physical and chemical properties in the laboratory. The results showed no significant differences (P >0.05) between the physical properties. The carbon levels, ranged from 1.58 % (El Guabo) to 2.06 % (Santa Rosa). In general, the nitrogen was low (0.16 % a 0.18 %). The values of: CE (0.13 13 dS/m to -0.21 dS/m), pH (6.46 to 7.72), CIC (23.4040 cmol/kg to -43.86 cmol/kg), potassium (0.310.31 cmol/kg to -1.86 cmol/kg) and calcium (19.99 cmol/kg to -37.73 cmol/kg) tended to be higher in Machala soils (< 0.05) and lower in Pasaje soils. The soils of Santa Rosa had higher concentrations of copper (16.6 mg/k) (P < 0.05) than in the rest of the municipalities. Cocoa yield CCN51 (2 570.24 kg/ha/y to 4 158.34 kg/ha/y) was higher than National (324.00 kg/ha/y to 814.17 kg/ha/y). The soils of Machala presented higher nutritional values, associated with higher average yield for National variety cocoa, and a high yield for CCN51 variety.

Cloning and expression analysis of LncRNA-RgAGT2 responding to consecutive monoculture in Rehmannia glutinosa / 中国中药杂志

The consecutive monoculture obstacle is a major problem in the field of Rehmannia glutinosa( R. glutinosa),has severely declined the yield and quality of R. glutinosa. Here,using hi TAIL-PCR and RACE techniques,we have cloned the full-length transcript( 1 573 bp) of Unigene 29334＿All screened by DGE as a consecutive monoculture obstacle response gene of R. glutinosa. Based on ORF Finder prediction,all ORFs detected in the full-length transcript were less than 300 nt,which suggested that the above transcript was confirmed to be a long non-coding RNA( LncRNA). With alignment in R. glutinosa transcriptome,this LncRNA was partially homologous to alanine glyoxylate transaminase 2 gene( Rg AGT2),which was named LncRNA-RgATG2. To further explore the function of LncRNA-RgAGT2,we have examined expression patterns of LncRNA-RgAGT2 and Rg AGT2 at five critical development stages( seedling,elongation,pre-expanding,mid-expanding,late-expanding) in the first and second year replanting of R. glutinosa,respectively. The results indicated that LncRNA-RgAGT2,as a potential regulator,is possible to play a vital role in Rg AGT2 expression regulation. Meanwhile,LncRNA-RgAGT2 has presented significant variation in all development stages of R. glutinosa,which could be used as a " diagnostic label" to assess consecutive monoculture obstacle. This study,for the first time,showed that LncRNA was responsible for the response and regulation of consecutive monoculture obstacle,which would be a powerful supplement to reveal the molecular mechanisms of consecutive monoculture obstacle of R. glutinosa.

Sobre a monocultura esportiva no ensino da educação física na escola / About the sportive monoculture in the teaching of physical education in school / Acerca de la monocultura esportiva en la enseñanza de la educación física en la escuela

A partir de uma etnografia, em que visamos compreender o processo de seleção dos conteúdos de três professores de Educação Física de uma escola pública gaúcha, emerge, de maneira significativa, o fenômeno do esporte na escola. A etnografia foi realizada durante um ano letivo inteiro, de intensificada observação participante, registros em diário de campo, diálogos, entrevistas e análise de documentos. Identificamos a hegemonia de um modelo esportivista, que privilegia o acesso de determinados grupos, destacando-se a formação de equipes, a representatividade da escola em eventos e a manifestação monocultural do futsal. Trata-se de uma seleção na qual os estudantes, de forma arbitrária, definem uma modalidade, a partir de seu gosto, e que é legitimada pelos professores, pela escola e pela comunidade.

From an ethnography where we intend to understand the process of selection of the contents of three Physical Education teachers of a public school in Rio Grande do Sul, the phenomenon of sports in the school emerge in a significant way. The ethnography was conducted in an entire school year, intensified participant observation, field diary records, dialogues, interviews and document analysis. We identified the hegemony of a sports model that privileges the access of certain groups, highlighting the formation of teams and the representativeness of the school in events and the monocultural manifestation of futsal. It is a selection where students, in an arbitrary way, define a modality, from their taste, and that is legitimized by the teachers, school and community.

A partir de una etnografía pretendemos comprender el proceso de selección de los contenidos de tres profesores de Educación Física de una escuela pública gaúcha, emergen de manera significativa el fenómeno del deporte en la escuela. La etnografía fue realizada en un año lectivo entero, de intensificada observación participante, registros en diario de campo, diálogos, entrevistas y análisis de documentos. Identificamos la hegemonía de un modelo deportivista que privilegia el acceso de determinados grupos, destacándose la formación de equipos y la representatividad de la escuela en eventos y la manifestación monocultural del futsal. Se trata de una selección donde los estudiantes definen una modalidad a partir de su gusto que es legitimada por los profesores, escuela y comunidad.

A consideration on screening of allelochemicals by using "knock-out/in" of targeting ingredients based on identification model of medicinal effect / 中国中药杂志

This paper clarified in detail the definition, characteristics of allelopathy and its association with consecutive monoculture problem.Most of studies have indicated that it is critical to parse the formation mechanisms of consecutive monoculture problem that identification of allelochemicals and verification of its function. Here, we proposed a new approach to separate and identify the allelochemical group precisely and effectively, in which the "knock-out/in" methods of targeting ingredients in the model of medicinal effect identification and quality control were applied. This method will contribute to deep understanding plant allelopathy, and provide theoretical basis and technical support for alleviating consecutive monoculture problems simultaneously.

Advances on molecular mechanisms of Rehmannia glutinosa consecutive monoculture problem formation in multi-omics era / 中国中药杂志

Although consecutive monoculture problems have been studied for many years, no effective treatments are currently available. The complexity of systems triggered the formation of consecutive monoculture problems was one major cause. This paper elaborated the physiological and ecological mechanisms of consecutive monoculture problem formation based on the interaction relationship among multiple factors presented in the rhizosphere soil of consecutive monoculture plants. At same time, in this paper the multiple interactions among cultivated medicinal plants, autotoxic allelochemicals and rhizosphere microbial were proposed to be most important causes that derived the formation of consecutive monoculture problem. The paper also highlighted the advantage of 'omics' technologies integrating plant functional genomics and metabolomics as well as microbial macro-omics in understanding the multiple factor interaction under a particular ecological environment. Additionally, taking R. glutinosa as an example, the paper reviewed the molecular mechanism for the formation of R. glutinosa consecutive monoculture problem from the perspective of the accumulation of allelopathic autotoxins, the rhizosphere microecology catastrophe and theresponding of consecutive monoculture plants. Simultaneously, the roles of mutilple 'omics' technologies in comprehending these formation mechanism were described in detail. This paper provides finally a new insight to solve systematically the mechanism of consecutive monoculture problem formation on molecular level.

Progress in improvement of continuous monoculture cropping problem in Panax ginseng by controlling soil-borne disease management / 中国中药杂志

The continuous monoculture cropping problem severely has hindered the land resource of Panax ginseng cultivation and threatened the sustainable development of ginseng industry. There are comprehensive factors causing the continuous monoculture cropping problem, such as deterioration of soil physical and chemical properties, accumulation of allelochemical, increase of pesticide residue and heavy metal, imbalance of rhizospheric micro-ecosystem, and increase of soil-borne diseases. Among soil-borne disease was one of the key factors. More than 40 soil-borne diseases have been reported in the ginseng cultivation, especially, the diseases were more serious in the ginseng replanting land. Here main soil-borne diseases and their prevention way have been summarized, and we try to provide the effective improvement strategy of continuous monoculture cropping problem focusing on the disease control and offer reference for overcoming the ginseng continuous monoculture cropping problem.

Sistema de cultivo e doses de nitrogênio na sanidade e no rendimento do milho / Cropping systens and nitrogen levels in the maize plant health and yield

As podridões da base do colmo (PBC) e grãos ardidos (GA) ocorrem em lavouras de milho, causando prejuízos aos produtores e contaminando os grãos com micotoxinas. O objetivo deste estudo foi quantificar os efeitos do monocultivo de milho, da rotação de culturas com feijoeiro e da adubação nitrogenada na incidência de PBC e GA, nos teores de fumonisinas, peso de mil sementes (PMS) e no rendimento de grãos de milho. O delineamento experimental adotado foi em blocos casualizados com parcelas subdivididas e quatro repetições por tratamento. Na parcela principal, foram testados três híbridos de milho: P30F36, AS 1575 e Maximus. Nas subparcelas, foi avaliada a resposta dos híbridos a cinco doses de nitrogênio (N), equivalentes a 0; 75; 140; 215 e 290kg de N ha-1, em ambos os sistemas de cultivo. Não foram observadas diferenças significativas para os valores médios de PBC, fumonisina e rendimento de grãos nos dois sistemas de cultivo avaliados. Para os valores médios de GA e PMS, ocorreram diferenças entre híbridos somente quando cultivados em rotação de cultura. A incidência dos parâmetros PBC e GA, quando em monocultura, foi superior aos encontrados quando cultivado em rotação de culturas. As variações médias do PMS e rendimento de grãos foram superiores quando em rotação, comparativamente ao sistema de cultivo em monocultura. As diferentes doses de N explicaram apenas parcialmente as variações observadas em todas as variáveis analisadas.

The stalk rot (SR) and grain rot (GR) occur in crops as corn, causing losses to farmers and contaminating the grain with mycotoxins. The aim of this study was to quantify the effects of corn monoculture, crop rotation with common bean, and nitrogen fertilization on the incidence of SR, GR, fumonisin levels, weight of thousand seeds (WTS) and grain yield. The experiment was randomized blocks with split plot and four replicates per treatment. In the main plot were tested three maize hybrids: P30F36, AS 1575 and Maximus. In the sub-plots, each of the hybrids was evaluated in five levels of nitrogen (N), equivalent to 0; 75; 140; 215 and 290kg of N ha-1 in both cropping systems. There were no significant differences for mean values of SR, Fumonisin and grain yield in both cropping systems evaluated. For GR and WTS average values had differences between hybrids only when corn was grown in crop rotation with common bean. The annual growth rate of SR and GR parameters in corn monoculture ranged from 44.8 to 172.4 %, above the rate found on corn when grown in crop rotation. In turn, mean changes of WTS and grain yield was 1.2 to 17.6 % higher when in rotation compared to monoculture cropping system. The differences found in nitrogen rates partly explained the changes observed in all variables.

Azteca barbifex Forel (Hymenoptera: Formicidae): potential pest of citrus crops in eastern Amazon

Damage caused by the ant Azteca barbifex (Forel) was identified in orange trees (Citrus sinensis), in Capitão Poço County, Guamá microregion, Pará State. The damage caused by the scraping of stems and branches lead to reduction in yield with subsequent death of the plant. These characteristics indicate A. barbifex as a potential pest of citrus crops in the eastern region of Amazon.

Regeneración natural de plantas leñosas en una plantación costarricense de Vochysia guatemalensis (Vochysiaceae) y el efecto de la fertilización con P y NPK / Natural regeneration of woody species in a Costa Rican plantation of Vochysia guatemalensis (Vochysiaceae) and the effect of P and NPK fertilization

Natural regeneration of woody species in a Costa Rican plantation of Vochysia guatemalensis (Vochysiaceae) and the effect of P and NPK fertilization. Forest plantation management strategies, including the selection of species, may have positive or negative effects over plant regeneration in the tropics. in this case, understory woody plants density and richness were studied in Tabarcia de Mora, Costa Rica, in a monoculture of Vochysia guatemalensis (ten year old plantation). Nineteen 80 m²plots, with several fertilization treatments (0-0; 0-50; 50-0, 50-50 g/plant of P, and NPK, during the first years, P placed once at the hole) in a completely randomized factorial design, were analyzed. Afterwards, the NPK fertilizer was increased from 150 to 200 g/ plant/year until the plantation was six year old. The plots, established after the coffee plantation was eliminated, had a minimum management schedule, basically the elimination of herbaceous vegetation once or twice a year during the first three years, and a tree thinning when the plantation was four year old, to increase spacing from 2x2 to 4x4 m. All woody vegetation taller than 0.5 m was tallied. A total of circa 10 000 ind/ha, distributed in 90 species, were found, mostly native of the region, some identified for forestry use, others important for the fauna. The majority of the species had low relative densities and frequencies. Sixteen percent of the plants reached heights greater than 2.5 m. Several factors seem to explain this regeneration pattern: a canopy with an intermediate openness, a low intensity forestry management, the nearness of the plantation to a mature forest fragment, and that the Vochysia plantation substituted a coffee plantation where soil conservation strategies and an annual fertilization management plan were applied. Finally, plots with only P had significantly higher species richness and abundance (χ2=15.364, gl=3, p=0.002) probably because the trees in this treatment were less developed (when compared with the others). Rev. Biol. Trop. 57 (Suppl. 1): 111-118. Epub 2009 November 30.

Las estrategias de manejo y las especies seleccionadas en plantaciones forestales pueden tener efectos positivos o negativos sobre la regeneración vegetal en los trópicos. Esta investigación estudió la abundancia y riqueza de plantas leñosas bajo el dosel de un monocultivo de Vochysia guatemalensis de diez años. Se evaluaron 19 parcelas de 80 m²en Tabarcia de Mora, con varios tratamientos de fertilización (0-0; 0-50; 50-0, 50-50 g/ planta de P, y NPK, respectivamente, este ultimó se aumentó de 150 a 200 g hasta que la plantación alcanzó los seis años), en un diseño factorial totalmente al azar. Se contaron e identificaron todas las especies leñosas con más de 0.5 m de altura, con un total de aproximadamente 10 000 ind/ha en 90 especies, siendo éstas principalmente nativas de la zona (varias maderables, otras importantes para la fauna), la mayoría con bajos índices de importancia (suma de la densidad y frecuencias relativas). Un 16% alcanzaron alturas superiores a 2.5 m. Se considera que varios factores pudieron favorecer dicha regeneración, como un dosel con una apertura inter-media, un manejo forestal de bajo impacto, la cercanía de un fragmento boscoso maduro, y el establecimiento de la plantación en sustitución de un cafetal donde se aplicaban estrategias de conservación de suelos y se fertilizaba anualmente. Finalmente, se determinó una mayor abundancia y riqueza en las parcelas con solo P (χ²=15.364, gl=3, p=0.002), probablemente porque los árboles de Vochysia tendieron a ser menos desarrollados en comparación con los otros tratamientos.

Water use in four model tropical plant associations established in the lowlands of Costa Rica

We examined soil water use patterns of four model plant associations established in the North Caribbean lowlands of Costa Rica by comparing the stable hydrogen isotope composition, δD, in xylem sap and in soil water at different depths, under rainy and dry conditions. Four 5-year-old model plant associations composed of 2 tree species (Hyeronima alchorneoides and Cedrela odorata) having different architecture and phenology were studied. Average tree height was 8.9 and 7.6 m, respectively. Each tree species was grown in monoculture and in polyculture with 2 perennial monocotyledons (Euterpe oleracea and Heliconia imbricata). Maximum rooting depth at the time of δD determination was ~ 2 m for almost all species. Most roots of all species were concentrated in the upper soil layers. Stomatal conductance to water vapor (gS) was higher in the deciduous C. odorata than in the evergreen H. alchorneoides; within each species, gS did not differ when the trees were grown in mono or in polyculture. During the rainy season, gradients in soil water δD were not observed. Average rainy season xylem sap δD did not differ among members of the plant combinations tested (-30 ‰), and was more similar to δD values of shallow soil water. Under dry conditions, volumetric soil water content declined from 50 to ~ 35%, and modest gradients in soil water δD were observed. xylem sap δD obtained during dry conditions was significantly lower than rainy season values. xylem sap δD of plants growing in the four associations varied between -9 and -22‰, indicating that shallow water was predominantly absorbed during the dry period too. Differences in xylem sap δD of trees and monocots were also detected, but no significant patterns emerged. The results suggest that: a) the plant associations examined extracted water predominantly from shallow soil layers (<1 m), b) the natural isotopic variation in soil and plant water at the study site was low, and c) the plant mixes obtain water from more than a single soil layer simultaneously. Temporal factors were important in determining the competition and complementary relations observed among the trees and the perennial monocots. Under the prevailing environmental conditions, water use in these plant associations was determined largely by species-specific attributes such as biomass allocation to fine roots, phenology, and canopy architecture, and to a lesser extent by water limitations. Rev. Biol. Trop. 56 (4): 1947-1957. Epub 2008 December 12.

Examinamos los patrones de uso de agua del suelo de cuatro asociaciones vegetales establecidas en el Caribe norte de Costa Rica, comparando la composición isotópica del hidrógeno, δD, en la savia del xilema y en el agua del suelo en condiciones lluviosas y secas. Estudiamos cuatro asociaciones de cinco años de edad compuestas por dos árboles (Hyeronima alchorneoides y Cedrela odorata) con diferente arquitectura y fenología, cultivados en mono y policultivo con dos monocotiledóneas perennes (Euterpe oleracea y Heliconia imbricata). Las excavaciones mostraron que la profundidad máxima de las raíces fue de 2 m para casi todas las especies, y que la mayor densidad de raíces se encontraba en la superficie del suelo. La conductividad estomática (gS) fue mayor en el árbol caducifolio (C. odorata) que en el perennifolio (H. alchorneoides); dentro de cada especie, gS no difirió cuando los árboles fueron cultivados en mono o en policultivo. Los resultados sugieren que: a) las asociaciones examinadas extrajeron agua predominantemente de las capas superficiales del suelo (<1 m), b) la variación natural en el acceso al agua del suelo por parte de las especies, y en las propiedades del suelo, fue baja, y c) las combinaciones de plantas obtuvieron agua de varias capas del perfil del suelo simultáneamente. Los factores relacionados con el tiempo fueron importantes en la determinación de las relaciones de competencia y complementariedad observadas entre los árboles y las monocotiledóneas perennes. En las condiciones ambientales prevalecientes, el uso del agua por parte de estas asociaciones de plantas fue determinado más por atributos, como la asignación de biomasa a las raíces finas, la fenología, y las propiedades del dosel, que por limitaciones en la disponibilidad de agua.

Ocorrência de Dyscinetus rugifrons Burmeister (Scarabaeidae: Dynastinae, Cyclocephalini) em plantios de palmeira-real-da-austrália (Archontophoenix spp. H. Wendl. & Drude), no Vale-do-Itajaí, SC / Ocurrence of Dyscinetus rugifrons Burmeister (Scarabaeidae: Dynastinae, Cyclocephalini) in Australian palm (Archontophoenix spp. H. Wendl. & Drude) plantations, in Vale do Itajaí, Santa Catarina State, Brazil

Pela primeira vez no Vale do Itajaí, SC, foi registrada a ocorrência de Dyscinetus rugifrons (Burmeister) atacando plantios de Archontophoenix spp. O inseto foi observado no município de Barra da Sul, causando dano em plantas jovens. O ataque causa a morte das plantas e na área levantada, cerca de 45 por cento das plantas foram atacadas. A importância em se manter os plantios de Archontophoenix spp. deve-se ao fato de que a mesma serve como alternativa à extração de palmito-juçara (Euterpe edulis), espécie nativa que vem tendo sua regeneração comprometida pelo extrativismo ilegal.

For the first time in the Vale do Itajaí, Santa Catarina State, was registered the occurrence of Dyscinetus rugifrons (Burmeister) attacking plantations of Archontophoenix spp. The insect was observed in the Barra do Sul city, causing damages in young plants. The attack caused plant death and in the surveyed area 45 percent of the plants were attacked. The importance in keeping Archontophoenix spp. plantations is that it is an alternative to palmito-juçara (Euterpe edulis) harvesting, a native specie that has its regeneration compromised for the illegal extrativism.