Temporal abundance of Aedes aegypti in Manaus, Brazil, measured by two trap types for adult mosquitoes

A longitudinal study was conducted in Manaus, Brazil, to monitor changes of adult Aedes aegypti (L.) abundance. The objectives were to compare mosquito collections of two trap types, to characterise temporal changes of the mosquito population, to investigate the influence of meteorological variables on mosquito collections and to analyse the association between mosquito collections and dengue incidence. Mosquito monitoring was performed fortnightly using MosquiTRAPs (MQT) and BG-Sentinel (BGS) traps between December 2008-June 2010. The two traps revealed opposing temporal infestation patterns, with highest mosquito collections of MQTs during the dry season and highest collections of BGS during the rainy seasons. Several meteorological variables were significant predictors of mosquito collections in the BGS. The best predictor was the relative humidity, lagged two weeks (in a positive relationship). For MQT, only the number of rainy days in the previous week was significant (in a negative relationship). The correlation between monthly dengue incidence and mosquito abundance in BGS and MQT was moderately positive and negative, respectively. Catches of BGS traps reflected better the dynamic of dengue incidence. The findings help to understand the effects of meteorological variables on mosquito infestation indices of two different traps for adult dengue vectors in Manaus

Sorghum yield after liming and combinations of phosphorus sources

ABSTRACT Phosphate fertilization has increased sorghum yield, but few studies are available on sorghum production and efficient fertilizer management related to liming and phosphorus (P) sources. This work evaluates production, dry matter partitioning and agronomic efficiency (AEI) in successive sorghum cycles after application of limestone and combinations of phosphorus sources. Two cycles were conducted in sequence in the same experimental field, in a 2 x 6 factorial scheme, corresponding to soil with or without liming and six combinations of P2O5 sources: control (0 kg ha-1 P2O5), 100% Itafós natural phosphate (NP), 75% NP + 25% single superphosphate (SS), 50% NP + 50% SS, 25% NP + 75% SS and 100% SS. Pots with capacity for 8 dm3 were used in a randomized block design with four replicates. The first cycle, conducted in the summer/autumn season, reached the highest dry matter production and P accumulation in treatments with higher SS proportions, leading to higher AEI. Subsequently, in the second cycle, conducted considering only the residual phosphate fertilization of the first cycle, highest dry matter production and AEI were obtained in the treatment with 100% or higher proportions of natural phosphate in the presence of liming, most likely due to the gradual release of P

Sorghum yield after liming and combinations of phosphorus sources

<div><p>ABSTRACT Phosphate fertilization has increased sorghum yield, but few studies are available on sorghum production and efficient fertilizer management related to liming and phosphorus (P) sources. This work evaluates production, dry matter partitioning and agronomic efficiency (AEI) in successive sorghum cycles after application of limestone and combinations of phosphorus sources. Two cycles were conducted in sequence in the same experimental field, in a 2 x 6 factorial scheme, corresponding to soil with or without liming and six combinations of P2O5 sources: control (0 kg ha-1 P2O5), 100% Itafós natural phosphate (NP), 75% NP + 25% single superphosphate (SS), 50% NP + 50% SS, 25% NP + 75% SS and 100% SS. Pots with capacity for 8 dm3 were used in a randomized block design with four replicates. The first cycle, conducted in the summer/autumn season, reached the highest dry matter production and P accumulation in treatments with higher SS proportions, leading to higher AEI. Subsequently, in the second cycle, conducted considering only the residual phosphate fertilization of the first cycle, highest dry matter production and AEI were obtained in the treatment with 100% or higher proportions of natural phosphate in the presence of liming, most likely due to the gradual release of P.</p></div

Frações de fósforo no solo em resposta à adubação fosfatada em um Latossolo com diferentes históricos de uso

No sistema plantio direto existe tendência de melhor aproveitamento do P, sobretudo em áreas cultivadas há mais tempo, mas há, ainda, necessidade de confirmação deste fato. Este trabalho teve como objetivo quantificar as frações inorgânicas e orgânicas de P e avaliar as respostas a diferentes doses de P do feijoeiro (Phaseolus vulgaris L.) e braquiária (Brachiaria decumbens) cultivados em sucessão, em amostras de um Latossolo com diferentes históricos de uso. O experimento foi realizado em casa de vegetação com amostras de um Latossolo Vermelho distrófico textura argilosa e oxídico, coletadas na profundidade de 0-20 cm. O experimento foi disposto em delineamento inteiramente casualizado, em esquema fatorial 2 x 4 com quatro repetições, com dois históricos de uso (solo agrícola cultivado por longos períodos com calagem e adubações fosfatadas periódicas; e solo adjacente sob vegetação de cerrado nativo) e quatro doses de P (0, 120, 240 e 480 mg dm-3, na forma de superfosfato triplo, com base no teor de P2O5 total). Foi realizado cultivo de feijão até a colheita dos grãos e, posteriormente, cultivo de braquiária com dois cortes no momento de florescimento das plantas. As frações de P foram determinadas em amostras de solo das unidades experimentais, antes e após a incubação dos tratamentos e após os cultivos do feijoeiro e da braquiária. A adubação fosfatada aumentou as formas inorgânicas de P no solo, as quais foram maiores nos solos com histórico de cultivo e adubação. Ela também aumentou as formas orgânicas de P no solo, as quais foram maiores nos solos adjacentes sem histórico de cultivo e adubação, nas maiores doses de P e após cultivo de feijoeiro e braquiária. As respostas do feijoeiro e da braquiária à adubação fosfatada foram menores nos solos com histórico de cultivo e adubação

Detection and identification of TMV infecting tomato under protected cultivation in Paraná State

During an inspection in plastic houses in Sapopema, Paraná, 90% of tomato plants showed leaf abnormalities, probably associated with herbicide toxity. However, virus like symptoms developed in selected hosts after mechanical inoculatation. RT-PCR reactions using primers for an internal region within the movement protein gene of TMV and ToMV resulted in the amplification of a 409 bp cDNA fragment only by TMV primers. Deduced amino acids showed 100% identity when compared to TMV movement protein and 94% with ToMV. The RT-PCR protocol was efficient for quick and conclusive determination of virus species. The virus was purified and a polyclonal antiserum was raised for future surveys in tomato crops of Paraná. The partial genomic sequence obtained for TMV-Sapopema has been deposited under the accession number DQ173945, which is the first partial genomic sequence of an isolate of TMV from Brazil in the GenBank, and the first tomato virus isolate from Paraná to have some of its biological and molecular properties determined.<br>Durante uma inspeção em cultivos protegidos de tomate em Sapopema, Paraná, foram observadas anormalidades foliares em 90% das plantas, indicando possivelmente a existência de um problema de fitotoxidade causada por herbicidas. Todavia, os sintomas manifestados nas hospedeiras após os ensaios de inoculação mecânica revelaram que os sintomas estariam relacionados a uma infecção por Tobamovirus. As reações de RT-PCR com oligonucleotídeos específicos para uma região interna da proteína de movimento de dois vírus comuns em tomate, TMV e ToMV, resultaram na amplificação de um fragmento de 409 pares de bases, apenas com os oligonucleotídeos específicos para o TMV. Após o sequenciamento, os aminoácidos deduzidos apresentaram identidade de 100% quando comparados com as seqüências das proteínas de movimento de outros isolados do TMV, e 94% de identidade com seqüências do ToMV. A RT-PCR demonstrou ser um método eficiente para a rápida e conclusiva determinação da espécie viral envolvida na infecção do tomateiro. A seqüência parcial do genoma do isolado de TMV de Sapopema, está depositada no GenBank sob o número de acesso DQ173945, sendo esta a primeira seqüência genômica parcial de um isolado de TMV do Brasil, e conforme o nosso conhecimento, o primeiro isolado de TMV do Paraná a ter algumas de suas propriedades biológicas e moleculares determinadas. Um anti-soro policlonal foi produzido, o que permitirá futuros levantamentos da ocorrência de Tobamovirus nas principais áreas de cultivo de tomate do Paraná

Crescimento e nutrição da braquiária em função de fontes de fósforo Growth and nutrition of marandu-grass as a function of phosphorus sources

Avaliaram-se, em casa de vegetação, as contribuições de diferentes fontes de fósforo (P) aplicadas em amostras de Latossolo Vermelho distroférrico (LVdf) (350 mg dm-3 de P2O5) e de Neossolo Quartzarênico (NQ) (200 mg dm-3 de P2O5), coletadas nos municípios de Lavras (MG) e Itutinga (MG), respectivamente, na produção de matéria seca, no teor e acúmulo de P na parte aérea e raiz da Brachiaria brizantha cv. Marandu. Também foi avaliado o índice de eficiência agronômica (IEA) das fontes. O experimento foi conduzido em um delineamento experimental inteiramente casualizado, em esquema fatorial 2x4 (dois solos e quatro fontes de fósforo (Superfosfato Triplo (ST), Fosfato Reativo de Arad (FR), Fosfato Natural de Araxá (FA), e uma mistura ST+FR - na relação (1:1), com quatro repetições. A dose de fósforo foi baseada no teor de P2O5 total das fontes. Para a produção total de matéria seca e o acúmulo total de P, as fontes de maior solubilidade, como o ST, FR e a mistura ST/FR foram mais eficientes, principalmente no primeiro, terceiro e quarto cortes no LVdf e em todos os cortes no NQ. O teor total de P na braquiária ao final do último corte foi maior quando se aplicaram as fonte FR e ST+FR para o LVdf e, ST e ST+FR para o NQ. As fontes de fósforo influenciaram o IEA nos dois solos, que foi maior para as fontes de maior solubilidade.<br>The contribution of different phosphorus (P) sources applied, under greenhouse conditions, in a clayey dystrophic Red Latosol - Oxisol (LVdf)(350 mg dm-3 of P2O5) and a sandy Neosol - Entisol (NQ)(200 mg dm-3 of P2O5), collected from Lavras (MG) and Itutinga (MG) counties, respectively, on Braquiaria's (Brachiaria brizantha cv. Marandu) dry matter production, P content and accumulation were evaluated. Also agronomic efficiency index (AEI) of the P sources applied was measured. The experiment was carried out under a completely randomized 4x2 factorial, comparing four P sources (Triple superphosphate - TS, Arad reactive phosphate - RP, Araxá rock phosphate - AP, and a 1:1 ratio mixture TS+RP), with four replicates. The amount of P applied was based on the P2O5 content of each source. The forage was cultivated for four cuts. For total dry matter production and P accumulation, P sources of higher solubility, as TS, RP and TS+RP were more efficient, especially for the first, third and forth cuts in the LVdf soil and for all cuts for the NQ soil. By the last cut, Braquiaria's total P content was higher when RP and TS+RP sources were applied for the LVdf soil and TS and TS+RP for the NQ soil. The different P sources had influence on AEI on both soils, for the LVdf soil as for the NQ soil P sources of higher solubility (RP and TS+RP) presented higher AEI