Leishmania amazonensis DNA in wild females ofLutzomyia cruzi (Diptera: Psychodidae) in the state of Mato Grosso do Sul, Brazil

Studies on natural infection by Leishmania spp of sandflies collected in endemic and nonendemic areas can provide important information on the distribution and intensity of the transmission of these parasites. This study sought to investigate the natural infection by Leishmaniain wild female sandflies. The specimens were caught in the city of Corumbá, state of Mato Grosso do Sul (Brazil) between October 2012-March 2014, and dissected to investigate flagellates and/or submitted to molecular analysis to detect Leishmania DNA. A total of 1,164 females (77.56% of which were Lutzomyia cruzi) representing 11 species were investigated using molecular analysis; 126 specimens of Lu. cruziwere dissected and also submitted to molecular analysis. The infection rate based on the presence of Leishmania DNA considering all the sandfly species analysed was 0.69%; only Leishmania (Leishmania) amazonensis was identified in Lu. cruzi by the molecular analysis. The dissections were negative for flagellates. This is the first record of the presence of L. (L.) amazonensis DNA in Lu. cruzi, and the first record of this parasite in this area. These findings point to the need for further investigation into the possible role of this sandfly as vector of this parasite.

Cannibalism studies on eggs and newly hatched caterpillars in a wild population of Ascia monuste (Godart) (Lepidoptera, Pieridae)

Ascia monuste (Godart), also known as cabbage caterpillar, is considered herbivorous and specialist in Brassicaceae; however, it performs cannibalism. Experiments carried out in this work aimed to quantify the cannibalism occurrence in A. monuste, to verify whether cannibalism interferes in the species performance and to check whether cannibalism is influenced by the population size. The parameters used in order to evaluate the performance were time of development, adults weight and size, fecundity, oviposition and survival rate. Cannibalism occurred in all larval instars. There was a tendency to increase the cannibalism practice as the number of co-specific increased (potential preys). Cannibalism was more intense in larvae at the end of larval development. Generally, cannibalism did not interfere in the population performance. The most probable hypothesis for the occurrence of cannibalism in the conditions here studied would be the hypothesis of cannibalism as having the function of population control.

Influence of male nutritional conditions on the performance and alimentary selection of wild females of Anastrepha obliqua (Macquart)(Diptera, Tephritidae)

Influence of male nutritional conditions on the performance and alimentary selection of wild females of Anastrepha obliqua (Macquart) (Diptera, Tephritidae). The behavior of A. obliqua females is regulated by endogenous and exogenous factors and among these the presence of males. Experiments were carried out to investigate whether the presence of males and their nutritional condition may affect the behavior of self-selection feeding and the performance of A. obliqua females. Females were sorted in groups containing yeast-deprived females and males, and non-yeast-deprived females and males. The females were maintained apart from the males by a transparent plastic screen. Several yeast and sucrose combinations were offered to the females in a single diet block or in separate blocks. Ingestion, egg production, longevity and diet efficiency were determined. The non-yeast-deprived males positively influenced the females performance when the latter were fed with yeast and sucrose in distinct diet blocks. Performance was better in the groups without males and with yeast-deprived males where the females could not select the nutrient proportions (yeast and sucrose in a single diet block).

Selection of artificial hosts for oviposition by wild Anastrepha obliqua (Macquart) (Diptera, Tephritidae): influence of adult food and effect of experience

Several factors influence the selection of oviposition substrates by insects. The aim of the present work was to find answers to the following questions related to the oviposition behavior of Anastrepha obliqua. Can carbohydrates (glucose or sucrose) present in the adult diet have influence on the female preference for an oviposition substrate with similar composition? Can the previous experience with a host containing one of mentioned carbohydrates interfere in further selection of oviposition substrates? The results showed that the kind of carbohydrate present in the adult diet did not affect the female preference for an artificial oviposition substrate, neither when it was presented by itself nor in combination with brewer's yeast. The effect of experience in the oviposition behavior was observed when there was a previous contact with artificial oviposition substrates containing yeast and sucrose. The data are discussed in terms of the behavioral plasticity presented by this species in relation to feeding and oviposition behaviors.

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae)

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae). The specialist cabbage caterpillar Ascia monuste orseis (Lepidoptera, Pieridae) feeds on plants of the Brassicaceae family, but may eventually ingest conspecific eggs and larvae during the larval stage. The present study examines feeding behavior of 4th and 5th instar cabbage caterpillars in relation to sex, host-plant deprivation and presence of conspecifics. We recorded number of egg ingested per larvae, developmental indices and duration of feeding, exploratory and resting behavior. Kale deprived caterpillars presented high rates of cannibalism, development delay and decreased fecundity. Cannibalism rates were not influenced by the sex of the larvae. In general, the presence of conspecific eggs did not interfere with the frequency and duration of the categorical behavioral events. We conclude that food availability is a strong factor influencing the extent to which A. monuste orseis caterpillars cannibalize.

Fruit flies (Diptera, Tephritidae) and their parasitoids on cultivated and wild hosts in the Cerrado-Pantanal ecotone in Mato Grosso do Sul, Brazil

Fruit flies (Diptera, Tephritidae) and their parasitoids on cultivated and wild hosts in the Cerrado-Pantanal ecotone in Mato Grosso do Sul, Brazil. Information on frugivorous flies in cultivated or wild host plants and their parasitoids in the Cerrado-Pantanal ecotone in Aquidauana, Mato Grosso do Sul is presented and discussed. Fruit fly samples were collected weekly in specific fruit trees, and McPhail® traps were installed in the same trees for a period of two years. The fruit flies infested ripe and unripe fruits of Averrhoa carambola L., Schoepfia sp., Psidium guajava L. and Pouteria torta (Mart.) Radlk and mature fruits of Anacardium occidentale L. and Inga laurina (Sw.) Willd. Nineteen fruit fly species were obtained with the combination of sampling methods (collecting fruits and trapping), nine of them obtained with both methods, five found only in fruits and five only in traps. This is the first record of Anastrepha striata Schiner in a species of Sapotaceae, as well as for A. castanea Norrbom and A. daciformes Bezzi in Schoepfia sp. (Olacaceae), and for A. distincta Greene in fruits of P. guajava in the state of Mato Grosso do Sul. Fruit collections simultaneously associated with capture of fruit flies by McPhail traps in the same host plants are essential to understand the diversity of fruit flies and their relationship with hosts and parasitoids. Species of Braconidae and Pteromalidae were recovered, where Doryctobracon areolatus (Szépligeti) was the most abundant parasitoid in larvae of tephritids infesting both cultivated and wild host fruits.

Necrophagous diptera associated with wild animal carcasses in southern Brazil

Necrophagous Diptera associated with wild animal carcasses in southern Brazil. The aim of this study was to acquire a better knowledge concerning the diversity of necrophagous Diptera that develop on wild animal carcasses. For this purpose, the decomposition of six wild animal carcasses was observed in order to collect and identify the main species of necrophagous flies associated with the decomposition process. The carcasses were found on highways near the cities of Pelotas and Capão do Leão in the initial stage of decomposition, with no significant injuries or prior larval activity. Four wild animal models were represented in this study: two specimens of Didelphis albiventris Lund, 1840; two Tupinambis merianae Linnaeus, 1758; one Nothura maculosa Temminck, 1815; and one Cerdocyon thous Linnaeus, 1766. A total of 16,242 flies from 14 species were reared in the laboratory, where Muscidae presented the greatest diversity of necrophagous species. Overall, (i) carcasses with larger biomass developed a higher abundance of flies and (ii) the necrophagous community was dominated by Calliphoridae, two patterns that were predicted from published literature; and (iii) the highest diversity was observed on the smaller carcasses exposed to the lowest temperatures, a pattern that may have been caused by the absence of the generalist predator Chrysomya albiceps (Wiedemann, 1819). (iv) An UPGMA analysis revealed a similar pattern of clusters of fly communities, where the same species were structuring the groupings.

Nitrogen application timing and soil inorganic nitrogen dynamics under no-till oat/maize sequential cropping

The timing of N application to maize is a key factor to be considered in no-till oat/maize sequential cropping. This study aimed to evaluate the influence of pre-planting, planting and sidedress N application on oat residue decomposition, on soil N immobilisation and remineralisation and on N uptake by maize plants in no-till oat/maize sequential cropping. Undisturbed soil cores of 10 and 20 cm diameter were collected from the 0-15 cm layer of a no-till Red Latossol, when the oat cover crop was in the milk-grain stage. Two greenhouse experiments were conducted simultaneously. Experiment A, established in the 10 cm diameter cores and without plant cultivation, was used to asses N dynamics in soil and oat residues. Experiment B, established in the 20 cm diameter cores and with maize cultivation, was used to assess plant growth and N uptake. An amount of 6.0 Mg ha-1 dry matter of oat residues was spread on the surface of the cores. A rate of 90 kg N ha-1 applied as ammonium sulphate in both experiments was split in pre-planting, planting and sidedress applications as follows: (a) 00-00-00 (control), (b) 90-00-00 (pre-planting application, 20 days before planting), (c) 00-90-00 (planting application), (d) 00-30-60 (split in a planting and a sidedress application 31 days after emergence), (e) 00-00-00* (control, without oat residue) and (f) 90-00-00* (pre-planting application, without oat residue). The N concentration and N content in oat residues were not affected during decomposition by N fertilisation. Most of the fertiliser NH4+-N was converted into NO3--N within 20 days after application. A significant decrease in NO3--N contents in the 0-4 cm layer was observed in all treatments between 40 and 60 days after the oat residue placement on the soil surface, suggesting the occurrence of N immobilisation in this period. Considering that most of the inorganic N was converted into NO3- and that no immobilisation of the pre planting fertiliser N occurred at the time of its application, it was possible to conclude that pre-planting applied N was prone to losses by leaching. On the other hand, with split N applications, maize plants showed N deficiency symptoms before sidedress application. Two indications for fertiliser-N management in no-till oat/maize sequential cropping could be suggested: (a) in case of split application, the sidedress should be earlier than 30 days after emergence, and (b) if integral application is preferred to save field operations, this should be done at planting.

Perdas de solo e água em plantio de Acacia mangium wild e savana em Roraima, norte da Amazônia

Plantios florestais de Acacia mangium constituem uma alternativa cada vez mais adotada em áreas de savanas do norte da Amazônia (Roraima) e podem causar alterações significativas de características do solo. Neste sentido, o objetivo deste estudo foi determinar perdas de solo e de água por erosão, que ocorrem em escoamento superficial (run off) em savana nativa e plantios de acácia na região Amazônica. Para isso, foram instaladas em duas fazendas, Santa Rita e Araçá, localizadas no município de Bonfim, na região da Serra da Lua, calhas coletoras de sedimentos, acopladas a caixas d'água, em Argissolo Vermelho-Amarelo. Foram determinadas a granulometria, a densidade aparente (Dap), a resistência à penetração (RP) e a velocidade de infiltração (VIB), bem como parâmetros físicos relacionados a perdas de solo. O delineamento experimental utilizado foi o de blocos ao acaso, com três tratamentos: cobertura natural de savana (SV), plantio de Acacia mangium com um ano de idade (P1) e plantio de Acacia mangium com quatro anos de idade (P4), em três repetições. O experimento teve a duração de 12 meses (setembro de 2006 a agosto de 2007). Os resultados indicaram maiores perdas de solo e de água no plantio mais recente de acácia (P1), de savana nativa e do plantio com 4 anos (P4). Os resultados foram atribuídos à exposição do solo no período inicial de desenvolvimento da planta, ao selamento superficial e à coesão do solo. O pico de perdas de solo ocorreu nos meses de abril a agosto, sendo o tipo de cobertura vegetal o fator determinante para redução das perdas de solo e de água por erosão, sendo que as práticas de plantio no sentido do declive provavelmente agravaram as perdas de solo nos plantios de Acácia. Neste trabalho, a densidade do solo e o teor de matéria orgânica não representaram bons indicadores do tipo de manejo adotado na área.

Water-soluble nutrients in aerial plant parts of peanut and white oat as affected by lime and gypsum application

Lime and gypsum influence nutrient availability and uptake, as well as the content of organic acids in the aerial plant parts. These changes, quantified by plant analysis of soluble nutrients, may potentiate the effect of soil amendment, ensuring the sustainability of the no-tillage system. In this sense the effect of lime and gypsum surface application on the content of water-soluble nutrients in peanut and oat residues was evaluated. The experiment was conducted on an Oxisol in Botucatu (SP) in the growing seasons 2004/2005 and 2005/2006. It was arranged in a randomized block design in split plots with four replications, where lime rates represented the plots and presence or absence of gypsum application the subplots. Peanut was grown in summer and white oat in the winter in the entire experimental area. Gypsum applied to peanut increased soluble Ca only in the first season, due to the short period between product application and determination of soluble nutrient contents in the plant extract. Liming of peanut and oat increased soluble Ca, Mg, K contents, did not alter Cu content and reduced Zn, Mn and Fe contents in both years of cultivation. Gypsum on the other hand reduced the electrical conductivity of peanut (2004/2005 and 2005/2006) and white oat (2004/2005).

Leaf application of silicic acid to white oat and wheat

Silicon (Si) is beneficial to plants in several aspects, but there are doubts about the effectiveness of leaf application. The purpose of this work was to evaluate the effects of Si, applied in a newly developed stabilized silicic acid form to the leaf, on nutrition and yield of irrigated white oat and wheat. Two experiments were performed (one per crop) in winter 2008, in Botucatu-SP, Brazil. A completely randomized block design with 14 replications was used. Treatments consisted of a control (without Si application) and Si leaf spraying, at a rate of 2.0 L ha-1 of the commercial product containing 0.8 % soluble Si. Silicon rate was divided in three parts, i.e. applications at tillering, floral differentiation and booting stages. Silicon leaf application increased N, P, K, and Si concentrations in white oat flag leaf, resulting in higher shoot dry matter, number of panicles per m², number of grains per panicle and grain yield increase of 34 %. In wheat, Si leaf application increased K and Si concentrations, shoot dry matter and number of spikes per m², resulting in a grain yield increase of 26.9 %.

Biomass decomposition and nutrient release from black oat and hairy vetch residues deposited in a vineyard

A significant quantity of nutrients in vineyards may return to the soil each year through decomposition of residues from cover plants. This study aimed to evaluate biomass decomposition and nutrient release from residues of black oats and hairy vetch deposited in the vines rows, with and without plastic shelter, and in the between-row areas throughout the vegetative and productive cycle of the plants. The study was conducted in a commercial vineyard in Bento Gonçalves, RS, Brazil, from October 2008 to February 2009. Black oat (Avena strigosa) and hairy vetch (Vicia villosa) residues were collected, subjected to chemical (C, N, P, K, Ca, and Mg) and biochemical (cellulose - Cel, hemicellulose - Hem, and lignin - Lig content) analyses, and placed in litter bags, which were deposited in vines rows without plastic shelter (VPRWS), in vines rows with plastic shelter (VPRS), and in the between-row areas (BR). We collected the residues at 0, 33, 58, 76, and 110 days after deposition of the litter bags, prepared the material, and subjected it to analysis of total N, P, K, Ca, and Mg content. The VPRS contained the largest quantities and percentages of dry matter and residual nutrients (except for Ca) in black oat residues from October to February, which coincides with the period from flowering up to grape harvest. This practice led to greater protection of the soil surface, avoiding surface runoff of the solution derived from between the rows, but it retarded nutrient cycling. The rate of biomass decomposition and nutrient release from hairy vetch residues from October to February was not affected by the position of deposition of the residues in the vineyard, which may especially be attributed to the lower values of the C/N and Lig/N ratios. Regardless of the type of residue, black oat or hairy vetch, the greatest decomposition and nutrient release mainly occurred up to 33 days after deposition of the residues on the soil surface, which coincided with the flowering of the grapevines, which is one of the phenological stages of greatest demand for nutrients.

Isoenzymatic variability in wild potatoes

Two species of wild potato Solanum commersonii, subspecies commersonii and malmeanum, and S. chacoense, subspecies muelleri occur in southern Brazil. Their rusticity and easy adaptation to extreme climatic conditions make them valuable for breeding programs. The objective of this work was to analyze the isoenzymatic variability of 113 clones of wild potato subspecies. They were collected and maintained at Embrapa-Centro de Pesquisa Agropecuária de Clima Temperado, at Pelotas, RS, Brazil. Enzymes involved in energetic (group I) or in peripherical (group II) metabolism constituted the material used. Polyacrylamide horizontal gel electrophoresis was used to analyze peroxidase, aspartate transaminase, phosphoglucomutase and isocitrate dehydrogenase isoenzymes. Solanum spp. has considerable genetic variability for isoenzymatic patterns. Cluster analysis classified the clones into 51 subgroups, based on electrophoretic variants of group I enzymes, and into 89, when group II enzyme variants were added. Genotypic differentiation of S. chacoense muelleri in relation to S. commersonii commersonii and S. commersonii malmeanum is evident when expressed through similarity and cluster analysis.

Description of a pure seed fraction of oat through usual evaluations and radiographic images

The objective of this work was to evaluate the width and length incidence in a single seed fraction of oat [Avena sativa (L.)] cv. Cristal. The seeds were selected by a mechanical divider and by hand, and their correspondence to radiographic images in seeds with glumes and their caryopses. The width and length of the seeds with glumes and their caryopses were measured with electronic calliper, and their weight, with precision balance. Radiographic images of seeds with glumes were taken with an X-ray experimental equipment. The analyst selected seeds with glumes by the width and by the length previously determined and so with more weight, than that obtained by hand selection was slightly narrower, larger and lighter. The presence of the glumes masked the caryopses real dimensions (width and length), and conduced the analyst to select seeds that differed more by the width than by the length. The radiographic images showed the presence, or not, of caryopses inside the seed and its real dimensions. The mechanical partition method for seeds showed to be more efficient because the analyst subjectivity was not considered when the selection upon its dimensions was done. The X-ray analysis was a useful tool that complements the pure seed fraction selection as another factor of seed quality.

Desiccation, postharvest maturity and seed aging of tall oat-grass

The objectives of this work were to determine whether and at which seed physiological maturity stage the diquat desiccant affects the tall oat-grass (Arrhenatherum elatius) seed quality and yield, as well as the proper storage period between harvest and sowing. Diquat desiccation was evaluated in applications during milk or dough seed maturation stages. Seeds conventionally produced and stored under traditional storage conditions were used for the analyses. Seed samples were drawn every 30th day after harvest (DAH). After the 240th DAH, samples were drawn every 90th day up the to 690th DAH. The highest yield were obtained by desiccation applied at the beginning of the seed dough stage, with a satisfactory seed quality. Both final germination and seedling growth parameters achieved their maximum values between 180th and 240th DAH. Oat-grass seeds preserved satisfactory level of final germination (75%) up to 420th DAH. The application of diquat desiccant at the beginning of seed dough maturity stage can be a good solution for seed production of tall oat-grass. Early spring is the best sowing period for freshly harvested seeds of tall oat-grass regarding germination and seedling growth.