Multiresidue analysis of pesticides in water from rice cultures by on-line solid phase extraction followed by LC-DAD

An automated on-line solid phase extraction procedure followed by liquid chromatography with diode array detection was investigated for the determination of different classes of pesticides in water samples containing varied amount of humic substances. The different pesticides used were: carbendazin, carbofuran, atrazine, diuron, propanil, molinate, alachlor, parathion-ethyl, diazinon, trifluralin and the degradation products deisopropylatrazine and deethylatrazine. Humic substances extracted from a Brazilian sediment were used from 5 to 80 mg/l and their influence on recoveries was evaluated in neutral and acidic media. Recoveries higher than 70% were obtained for all the pesticides, from the preconcentration of 75 mi of aqueous sample fortified at 2 ng/ml using precolumns packed with PLRP-S. Good recoveries were obtained at neutral pH for most of the analytes up to 40 mg/l of humic acid. Only at 80 mg/l the recoveries were significantly affected, both at acidic and neutral pH. The method was applied to the determination of pesticides in river water spiked at 0.1 to 1 ng/ml. Detection limits obtained for water containing 10 mg/l of humic acid were between 0.05 and 0.3 ng/ml.

Qualidade fisiológica e sanitária de sementes de mamona submetidas a diferentes tratamentos químicos

The use of fungicides for treating seeds has become an essential measure in the control of pathogens. However, the effectiveness of many products is not well-known to some crops. The objective of this research was to evaluate the effect of different doses of carbendazin and carboxin + thiram fungicides for controlling pathogens and their interference on the physiologic quality of castor bean seeds. The test consisted of the following treatments (g i.a./100 kg of seeds): carbendazin (15, 30, and 60), carboxin + thiram (25 + 25, 50 + 50, and 100 + 100), formol 0.15% (v/v), and control (distilled water). The physiologic quality of the seeds was determined by germination, first counting, field emergence, speed emergence index, length, fresh and dry weight of the aerial part, and electrical conductivity. There were no statistical differences for germination and fresh and dry matter index. The treatment with formol provided lower values for first counting and field emergence. Seeds treated with fungicides presented higher values for electrical conductivity, but did not differ, statistically, among themselves. The fungi Cladosporium spp.; Bipolaris spp.; Curvularia spp.; Aspergillus flavus; Aspergillus niger; Rhizopus sp.; Penicillium sp.; Rhizoctonia sp.; Verticillium sp.; Fusarium sp.;Arthrobotrys sp.; and Epicocum sp. were identified. All tested products, independently of the dose, provided efficient control for pathogens.

Fungigação no controle do mofo branco e produtividade do feijoeiro em condições de cerrado brasileiro

The aim of this research was to evaluate the white mold severity (Sclerotinia sclerotiorum (Lib.) of Bary), bean production components and yield (Phaseolus vulgaris L.), variety Perola, according to the application of procimidone fungicide (Sialex 500), through fungigation (center pivot) and automotive sprayer (Uniport). The study was carried under field production commercial conditions, in Primavera do Leste - MT - Brazil. The experiment consisted of 5 treatments (with 4 repetitions of 4 ha each), all with two procimidone applications (1.2 kg ha-1 each application, same as, 0.6 kg a.i. per hectare) to the 42 and 52 days after seeding. The water depths of 5.5 and 11.0 mm were tested in the application through central pivot (this had your checked uniformity), providing volumes of 55.000 and 110.000 L ha-1, respectively, and the volumes of 120 and 200 L ha-1 in the automotive sprayer. The severity of disease was evaluated by the percentage of the area affected by plant damage using diagramatic grade scale of white mold severity, as described by Azevedo (1998). The values were used to calculate the area under the disease progress curve (AUDPC). They were also analyzed, the number of the fungus apothecia during the crop cycle and the residual sclerotias weight in harvest. On this occasion, it was also evaluated the crop yield parameters: number of plants per plot (final stand), pods per plant, grains per pod, medium weight of 200 grains and productivity of grains. The AUDPC values, apothecia to 42, 49 and 56 days after seeding, sclerotias in 2 soil kg and the crop productivity parameters were submitted to the variance analysis and Tukey Test at 0.05 of probability. This test was also applied in the comparison among the different fungicide application methods, independent of spray volumes in each one. The statistical processing was accomplished by STAT program. The results showed that weren't differences among application techniques studied in relation to productivity parameters, however, best white mold control, smaller apothecia number to 49 and 56 days after seeding and smaller weight of residual sclerotias in the harvest were obtained with the fungigation, independently of the spray volume used.

Assistência de ar e aplicação em volume baixo no controle da ferrugem asiática da soja (Phakopsora pachyrhizi Sydon & Sydon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Teste de envelhecimento acelerado em sementes de aveia preta (Avena strigosa Schreb.)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos fisiológicos da piraclostrobina em plantas de feijão (Phaseolus vulgaris L.) condicionado sob diferentes tensões de água no solo

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Depósito de pulverização em diferentes sistemas de semeadura de soja no manejo da ferrugem asiática

Pós-graduação em Agronomia (Agricultura) - FCA

Uso da Aloe vera L. no manejo de matrinxã (Brycon amazonicus)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atividade antimicrobiana de Mentha piperita L. sobre leveduras do gênero Candida

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Controle químico de doenças de Eucalyptus spp. em viveiros e seus efeitos morfo-fisiológicos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Syzygium cumini (L) Skeels-jambolão: estudo farmacognóstico, otimização do processo extrativo, determinação da atividade antimicrobiana do extrato e avaliação da atividade anti-séptica de um sabonete líquido contendo o referido extrato

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Evaporação de gotas de caldas contendo fungicidas e adjuvantes depositadas em superfície

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência de adjuvantes de calda no depósito e deriva em aplicações aéreas e terrestres

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Variação genética e adaptabilidade evolutiva de Rhizoctonia solani AG-1 da soja sob condições de estresse

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Atividade de monócitos em gestantes normais e com pré-eclâmpsia

Pós-graduação em Ginecologia, Obstetrícia e Mastologia - FMB