Host plants of Cerambycidae and Vesperidae (Coleoptera, Chrysomeloidea) from South America

Host plants of Cerambycidae and Vesperidae (Coleoptera, Chrysomeloidea) from South America. This paper offers a contribution to the knowledge on host plants of Cerambycidae and Vesperidae (Coleoptera, Chrysomeloidea) from South America. A total of 211 species of longhorn beetles belonging to 111 genera, 49 tribes, five subfamilies and two families are presented with records of host plants. Data on 259 species of host plants distributed among 188 genera and 69 families are listed with the beetle species.

Origin of samples of Cannabis sativa through insect fragments associated with compacted hemp drug in South America

Origin of samples of Cannabis sativa through insect fragments associated with compacted hemp drug in South America. Insects associated with a seizure of Cannabis sativa L. may indicate the origin of the illicit drug. Nevertheless, no work regarding this subject has been previously published for South America. In the present investigation, seven kilograms of vegetal material (C. sativa) were inspected for insect fragments. Three species were identified and used to test the origin of the seizure of cannabis plant material: Euschistus heros (Fabricius, 1794), Thyanta perditor (Fabricius, 1794) (Heteroptera, Pentatomidae), and Cephalotes pusillus (Klug, 1824) (Hymenoptera, Formicidae). These insect species restricted the geographic origin of the drug to the Neotropical region, and their distribution patterns showed an overlap of the State of Mato Grosso (Brazil), Argentina, and Paraguay. Based on this information, two of the three major C. sativa growing areas in South America were excluded: (1) the Colombian territory and (2) northeastern Brazil.

A survey of mealybugs infesting South-Brazilian wine vineyards

ABSTRACTMealybugs (Hemiptera: Pseudococcidae) are important pests of the grapevine Vitis spp. and are responsible for direct and indirect damage to production. The main mealybug species present in wine grapevine (Vitis vinifera L.) in Southern Brazil were identified and their incidence evaluated. Bunch-samples (n = 50) from 131 vineyards located in the Serra Gaúcha Region (RS) of Brazil were analyzed at harvest, and the occurrence of mealybugs in the roots was evaluated at the time of eradication of plants for replanting. Mealybugs were reared in laboratory until adulthood for species determination. The species Dysmicoccus brevipes (Cockerell, 1983), Dysmicoccus sp., Planococcus citri (Risso, 1813), Pl. minor(Maskell, 1897), Pseudococcus viburni (Signoret, 1875) and Pseudococcus sp. were identified in bunches. Dysmicoccus sp., D. umbambae Granara de Willink, 2009, Pl. citri and Pseudococcus sp. were found in the roots. Pl. citri (31.4%) and Dysmicoccus sp. (22.7%) were the most common species found in wine grape bunches in the Serra Gaúcha Region.

Spore communities of arbuscular mycorrhizal fungi and mycorrhizal associations in different ecosystems, south Australia

Communities of arbuscular mycorrhizal fungi (AMF) were surveyed in different South Australian ecosystems. The soil was wet-sieved for spore extraction, followed by the determination of presence and abundance of AMF species as well as the percentage of root colonization. Mycorrhizal associations were common and there was substantial fungal diversity in different ecosystems. Spores were most abundant in the permanent pasture system and less abundant under continuous wheat. The incidence of mycorrhizal associations in different plant species and the occurrence of Arum and Paris type colonization generally conformed with previous information. Spores of seventeen AMF were verified throughout seasonal changes in 1996 and 1997 in the permanent pasture and on four host species (Lolium perenne, Plantago lanceolata, Sorghum sp. and Trifolium subterraneum) , set up with the same soils under greenhouse conditions. Glomus mosseae was the dominant spore type at all sampling times and in all trap cultures. Mycorrhizal diversity was significantly affected by different sampling times in trap cultures but not in field-collected soil. P. lanceolata, Sorghum sp. and T. subterraneum as hosts for trap cultures showed no differences in richness and diversity of AMF spores that developed in association with their roots. Abundance and diversity were lowest, however, in association with L. perenne , particularly in December 1996. Results show that the combination of spore identification from field-collected soil and trap cultures is essential to study population and diversity of AMF. The study provides baseline data for ongoing monitoring of mycorrhizal populations using conventional methods and material for the determination of the symbiotic effectiveness of AMF key members.

Spodosols pedogenesis under barreiras formation and sandbank environments in the south of Bahia

Morphologically differentiated Spodosols usually occur in the Coastal Plain of the South of Bahia and North of Espírito Santo. They are found in profiles known as "muçungas", i.e. sandy soils that accumulate water. In these areas, two kinds of Spodosols, different from those in the Restinga area, can be found: Spodosols with E albic horizon (white muçunungas) and without this horizon (black muçunungas). Eight soil profiles with spodic characteristics were collected and described in order to evaluate differences in the formation process of Barreiras and Restinga Spodosols in the South of Bahia. The soil profiles were also characterized chemically, physically and mineralogically. Additionally, texture and chemical analysis, Fe and Al extraction by sodium dithionite-citrate-bicarbonate (DBC), acid ammonium oxalate and sodium pyrophosphate, ammonium oxalate extract optic density (DOox), sulphuric acid attack, and X ray difractometry of the clay fraction were performed. In the Spodosols of the Barreiras area, fragipan was found the spodic layers. Cemented B spodic horizon were observed in the white muçunungas, and granular structure and dark color from the surface in the black muçunungas. There was no fragipan or hard spodic horizon in the Restinga Spodosol. This soil is acid, dystrophic and alic, with sandy texture and high clay percentages in the spodic horizons. The CEC, based on H + Al, is predominantly represented by the organic matter. The most representative components of the mineral phase of the clay fraction are kaolinite and possibly vermiculite traces with interlayered hydroxy. Chemical, physical, morphological and mineralogical differences were observed between the Barreiras and Restinga environments. The black and white muçunungas differ in morphologic and chemical properties only.

Nitrous oxide and methane fluxes in south Brazilian gleysol as affected by nitrogen fertilizers

Nitrogen fertilizers increase the nitrous oxide (N2O) emission and can reduce the methane (CH4) oxidation from agricultural soils. However, the magnitude of this effect is unknown in Southern Brazilian edaphoclimatic conditions, as well as the potential of different sources of mineral N fertilizers in such an effect. The aim of this study was to investigate the effects of different mineral N sources (urea, ammonium sulphate, calcium nitrate, ammonium nitrate, Uran, controlled- release N fertilizer, and urea with urease inhibitor) on N2O and CH4 fluxes from Gleysol in the South of Brazil (Porto Alegre, RS), in comparison to a control treatment without a N application. The experiment was arranged in a randomized block with three replications, and the N fertilizer was applied to corn at the V5 growth stage. Air samples were collected from a static chambers for 15 days after the N application and the N2O and CH4 concentration were determined by gas chromatography. The topmost emissions occurred three days after the N fertilizer application and ranged from 187.8 to 8587.4 µg m-2 h-1 N. The greatest emissions were observed for N-nitric based fertilizers, while N sources with a urease inhibitor and controlled release N presented the smallest values and the N-ammonium and amidic were intermediate. This peak of N2O emissions was related to soil NO3--N (R² = 0.56, p < 0.08) when the soil water-filled pore space was up to 70 % and it indicated that N2O was predominantly produced by a denitrification process in the soil. Soil CH4 fluxes ranged from -30.1 µg m-2 h-1 C (absorption) to +32.5 µg m-2 h-1 C (emission), and the accumulated emission in the period was related to the soil NH4+-N concentration (R² = 0.82, p < 0.001), probably due to enzymatic competition between nitrification and metanotrophy processes. Despite both of the gas fluxes being affected by N fertilizers, in the average of the treatments, the impact on CH4 emission (0.2 kg ha-1 equivalent CO2-C ) was a hundredfold minor than for N2O (132.8 kg ha-1 equivalent CO2-C). Accounting for the N2O and CH4 emissions plus energetic costs of N fertilizers of 1.3 kg CO2-C kg-1 N regarding the manufacture, transport and application, we estimated an environmental impact of N sources ranging from 220.4 to 664.5 kg ha-1 CO2 -C , which can only be partially offset by C sequestration in the soil, as no study in South Brazil reported an annual net soil C accumulation rate larger than 160 kg ha-1 C due to N fertilization. The N2O mitigation can be obtained by the replacement of N-nitric sources by ammonium and amidic fertilizers. Controlled release N fertilizers and urea with urease inhibitor are also potential alternatives to N2O emission mitigation to atmospheric and systematic studies are necessary to quantify their potential in Brazilian agroecosystems.

Ammonia volatilization in no-till system in the south-central region of the State of Paraná, Brazil

Ammonia (NH3) volatilization can reduce the efficiency of urea applied to the surface of no-till (NT) soils. Thus, the objectives of this study were to evaluate the magnitude of NH3 losses from surface-applied urea and to determine if this loss justifies the urea incorporation in soil or its substitution for other N sources under the subtropical climatic conditions of South-Central region of Paraná State, Brazil. The experiment, performed over four harvesting seasons in a clayey Hapludox followed a randomized block design with four replicates. A single dose of N (150 kg ha-1) to V5 growth stage of corn cultivated under NT system was applied and seven treatments were evaluated, including surface-applied urea, ammonium sulfate, ammonium nitrate, urea with urease inhibitor, controlled-release N source, a liquid N source, incorporated urea, and a control treatment with no N application. Ammonia volatilization was evaluated for 20 days after N application using a semi-open static system. The average cumulative NH3 loss due to the superficial application of urea was low (12.5 % of the applied N) compared to the losses observed in warmer regions of Southeastern Brazil (greater than 50 %). The greatest NH3 losses were observed in dry years (up to 25.4 % of the applied N), and losses decreased exponentially as the amount of rainfall after N application increased. Incorporated urea and alternative N sources, with the exception of controlled-release N source, decreased NH3 volatilization in comparison with surface-applied urea. Urea incorporation is advantageous for the reduction of NH3 volatilization; however, other aspects as its low operating efficiency should be considered before this practice is adopted. In the South-Central region of Paraná, the low NH3 losses from the surface-applied urea in NT system due to wet springs and mild temperatures do not justify its replacement for other N sources.

Wheat yield and physical properties of a brown latosol under no-tillage in south-central Paraná

Soil management influences the chemical and physical properties of soil. Chemical conditions have been thoroughly studied, while the role of soil physical conditions regarding crop yield has been neglected. This study aimed to analyze the wheat yield and its relationship with physical properties of an Oxisol under no-tillage (NT). The study was carried out between 2010 and 2011, in Reserva do Iguaçu, State of Paraná, Brazil, on the Campo Bonito farm, after 25 years of NT management. Based on harvest maps of barley (2006), wheat (2007) and maize (2009) of a plot (150 ha), zones with higher and lower yield potential (Z1 and Z2, respectively) were identified. Sampling grids with 16 units (50 x 50 m) and three sampling points per unit were established. The wheat grain yield (GY) and water infiltration capacity (WIC) were evaluated in 2010. Soil samples with disturbed and undisturbed structure were collected from the 0.00-0.10 and 0.10-0.20 m layers. The former were used to determine soil organic carbon (Corg) levels and the latter to determine soil bulk density (BD), total porosity (TP), macroporosity (Mac), and microporosity (Mic). Soil penetration resistance (PR) and water content (SWC) were also evaluated. The wheat GY of the whole plot was close to the regional average and the yield between the zones differed significantly, i.e. 22 % higher in Z1 than in Z2. No significant variation in Mic was observed between zones, but Z1 had higher Corg levels, SWC, TP and Mac and lower BD than Z2 in both soil layers, as well as a lower PR than Z2 in the 0.00-0.10 m layer. Therefore, soil physical conditions were more restrictive in Z2, in agreement with wheat yield and zone yield potential defined a priori, based on the harvest maps. Soil WIC in Z1 was significantly higher (30 %) than in Z2, in agreement with the results of TP and Mac which were also higher in Z1 in both soil layers. The correlation analysis of data of the two layers showed a positive relationship between wheat GY and the soil properties TP, SWC and WIC.

Boundary between Soil and Saprolite in Alisols in the South of Brazil

Despite numerous studies conducted on the lower limit of soil and its contact with saprolite layers, a great deal of work is left to standardize identification and annotation of these variables in the field. In shallow soils, the appropriately noting these limits or contacts is essential for determining their behavior and potential use. The aims of this study were to identify and define the field contact and/or transition zone between soil and saprolite in profiles of an Alisol derived from fine sandstone and siltstone/claystone in subtropical southern Brazil and to subsequently validate the field observations through a multivariate analysis of laboratory analytical data. In the six Alisol profiles evaluated, the sequence of horizons found was A, Bt, C, and Cr, where C was considered part of the soil due to its pedogenetic structure, and Cr was considered saprolite due to its rock structure. The morphological properties that were determined in the field and that were different between the B and C horizons and the Cr layer were color, structure, texture, and fragments of saprolite. According to the test of means, the properties that support the inclusion of the C horizon as part of the soil are sand, clay, water-dispersible clay, silt/clay ratio, macroporosity, total porosity, resistance to penetration, cation exchange capacity, Fe extracted by DCB, Al, H+Al, and cation exchange capacity of clay. The properties that support the C horizon as a transition zone are silt, Ca, total organic C, and Fe extracted by ammonium oxalate. Discriminant analysis indicated differences among the three horizons evaluated.

Colonization by mites of glacier-free areas in King George Island, Antarctica

This work aimed to investigate the ratio of colonization by terrestrial mites on ice-free areas created by the ongoing climate-induced melting of Antarctic glaciers. Glacier retreat opens new ice-free areas for the colonization by vegetation and animals. The study was undertaken on the Antarctic Specially Protected Area no. 128 (West Coast of the Admiralty Bay, King George Island, South Shetlands Islands). Transects marked between the Ecology, Baranowski and Windy Glaciers, and a sea shore were used to collect soil samples. Oribatid mites were found only on near-shore areas, on patches of vegetation of more than 30 years of age. The colonization by mite communities is strongly determined by the presence of plants.

Dynamics and vertical distribution of a Hrabeiella periglandulata (Annelida) population in South Moravia, Czech Republic

The objective of this work was to evaluate the density, dynamics and vertical distribution of a Hrabeiella periglandulata population in a forest soil at Brno, Czech Republic. From December 2003 to November 2004, two plots covered by mixed stands and two covered by coniferous stands were sampled monthly. Six soil cores per plot were taken down to 15 cm and subdivided into layers, which were subjected to wet funnel extraction. Missing in one of the coniferous stands H. periglandulata was abundant in the mixed stand with the highest soil pH. In this stand, monthly sampling continued until November 2005, with three additional samplings up to January 2007. Mean annual density was 2,672±1,534 individuals m-2. Population dynamics differed from those reported from Germany. Highest densities were reached in early summer, lowest between August and December. Due to aggregated horizontal distribution, differences between monthly values were often nonsignificant. No significant correlation with climatic data was found. Nevertheless, the observed dynamics corresponded to the climatic conditions, showing particularly the negative effect of drought. The population was evenly distributed in the sampled soil profile, only avoiding the organic layer. Except for a locality in Poland, this is the easternmost record of the species.

Spatiotemporal dynamics of soil rotifers in a South-Bohemian beech forest

The objective of this work was to determine seasonal variation and vertical distribution of the soil rotifer assemblage in a climax beech forest in South Bohemia. During 2005, soil rotifer was investigated to the species level. Soil samples of 10 cm² and 10 cm in depth were divided into five layers, which were processed separately. Thirty one rotifer species were identified during the investigation. Dominant species significantly changed throughout the seasons. The most abundant species were Encentrum arvicola and Wierzejskiella vagneri among the monogononts, and Adineta steineri, Ceratotrocha cornigera, Habrotrocha filum, Habrotrocha ligula, Macrotrachela plicata, Mniobia tentans, Mniobia incrassata and Mniobia granulosa among the bdelloids. Mean Shannon diversity index varied from 1.99 to 2.63. Total rotifer abundance varied from 212±63 to 513±127 10³ individuals m-2 along the year, with the highest numbers found in May, and the lowest in July. The great part of the community was concentrated in the upper (fresh litter) and second (partially decomposed litter) layers and significantly decreased in the soil vertical profile on all sampling dates. The highest rotifer density of 43 individuals g-1 was found in the upper layer in May.

Performance of 'Oneco' mandarin on six rootstocks in South Brazil

The objective of this work was to assess the effect of six rootstocks on yield, fruit quality, and growth of 'Oneco' mandarin during the first seven harvesting seasons, in Butiá, Rio Grande do Sul State, Brazil. The rootstocks evaluated were: 'Swingle' citrumelo (Citrus paradisi × Poncirus trifoliata), 'Caipira' orange (C. sinensis), 'Troyer' citrange (C. sinensis × P. trifoliata), 'Rangpur' lime (C. limonia), 'Volkamer' lemon (C. volkameriana), and 'Flying Dragon' trifoliata orange (P. trifoliata var. monstrosa). Plants budded onto 'Flying Dragon' had the lowest vegetative development, which indicates the dwarfing characteristics of this rootstock, and had the highest mean production efficiency, despite low yield. Plants grafted on 'Volkamer' lemon and 'Rangpur' lime had the highest alternate bearing. Under the experimental conditions evaluated, the most adequate rootstocks for mandarin 'Oneco' are 'Swingle' citrumelo and 'Troyer' citrange, regarding fruit yield and quality.

Assessment of rubber tree panels under crowns resistant to South American leaf blight

The objective of this work was to assess the performance of panel clones under crowns resistant to South American leaf blight (Microcyclus ulei). The experiment was carried out with 18 panel clones crown-budded with Hevea pauciflora x H. guianensis, in a Xanthic Ferralsol (Oxisol) in Manaus, AM, Brazil. The following parameters were evaluated: dry rubber yield, plant nutritional status, and anatomical and physiological characteristics of the latex vessels. In the first three years of evaluation, the panel clones IAN 2878, IAN 2903, CNS AM 7905, CNS AM 7905 P1, and PB 28/59 showed the highest dry rubber yield potential, while the clones IAN 6158, IAN 6590, and IAN 6515 should not be recommended for crown budding. Higher potassium and copper foliar content in panel clones were associated to an increase in dry rubber yield. The simultaneous evaluation of anatomical and physiological characteristics of latex is fundamental for the selection of panel clones in the Amazon region. Crown budding is an efficient technology for South American leaf blight management in endemic regions.

Soil organic matter in fire-affected pastures and in an Araucaria forest in South-Brazilian Leptosols

The objective of this work was to evaluate the distribution pattern and composition of soil organic matter (SOM) and its physical pools of Leptosols periodically affected by fire over the last 100 years in South Brazil. Soil samples at 0-5, 5-10, and 10-15 cm depths were collected from the following environments: native pasture without burning in the last year and grazed with 0.5 livestock per hectare per year (1NB); native pasture without burning in the last 23 years and grazed with 2.0 livestock per hectare per year (23NB); and an Araucaria forest (AF). Physical fractionation was performed with the 0-5 and 5-10 cm soil layers. Soil C and N stocks were determined in the three depths and in the physical pools, and organic matter was characterized by infrared spectroscopy and thermogravimetry. The largest C stocks in all depths and physical pools were found under the AF. The 23NB environment showed the lowest soil C and N stocks at the 5-15 cm depth, which was related to the end of burning and to the higher grazing intensity. The SOM of the occluded light fraction showed a greater chemical recalcitrance in 1NB than in 23NB. Annual pasture burning does not affect soil C stocks up to 15 cm of depth.