PMID(sorted descending)
spatial analysis of the distribution of spodoptera frugiperda (j.e. smith) (lepidoptera: noctuidae) and losses in maize crop productivity using geostatistics.the fall armyworm, spodoptera frugiperda (j.e. smith), is one of the chief pests of maize in the americas. the study of its spatial distribution is fundamental for designing correct control strategies, improving sampling methods, determining actual and potential crop losses, and adopting precise agricultural techniques. in são paulo state, brazil, a maize field was sampled at weekly intervals, from germination through harvest, for caterpillar densities, using quadrates. in each of 200 quadrates, ...200818641904
sporulation and diversity of arbuscular mycorrhizal fungi in brazil pine in the field and in the greenhouse.the aim of this work was to assess the sporulation and diversity of arbuscular mycorrhizal fungi (amf) at different forest sites with araucaria angustifolia (bert.) o. ktze. (brazil pine). in addition, a greenhouse experiment was carried out to test the use of traditional trap plants (maize + peanut) or a. angustifolia to estimate the diversity of amf at each site. soil samples were taken in two state parks at southwestern brazil: campos do jordão (parque estadual de campos do jordão [pecj]) and ...200717342509
leaf wetness duration measurement: comparison of cylindrical and flat plate sensors under different field general, leaf wetness duration (lwd) is a key parameter influencing plant disease epidemiology, since it provides the free water required by pathogens to infect foliar tissue. lwd is used as an input in many disease warning systems, which help growers to decide the best time to spray their crops against diseases. since there is no observation standard either for sensor or exposure, lwd measurement is often problematic. to assess the performance of electronic sensors, lwd measurements obtained ...200717124590
characterization and genetic variability of fusarium verticillioides strains isolated from corn and sorghum in brazil based on fumonisins production, microsatellites, mating type locus, and mating crosses.fusarium verticillioides (gibberella fujikuroi mating population a) is a producer of fumonisins and one of the main contaminants of corn grains. in brazil, some studies analyzing strains isolated from corn have demonstrated high levels of fumonisins, whereas the levels for strains isolated from sorghum have been found to be low. in the present study, we investigated the genetic diversity of 22 f. verticillioides strains isolated from corn and 21 strains isolated from sorghum cultivated in the st ...200616917539
using thermal units for estimating critical period of weed competition in off-season maize crop.brazilian off-season maize production is characterized by low yield due to several factors, such as climate variability and inadequate management practices, specifically weed management. thus, the goal of this study was to determinate the critical period of weed competition in off-season maize (zea mays l.) crop using thermal units or growing degree days (gdd) approach to characterize crop growth and development. the study was carried out in experimental area of the university of são paulo, braz ...200515656156
fumonisins in brazilian corn-based foods for infant consumption.a survey of 196 samples of corn-based infant foods from 13 cities of sao paulo state, brazil, was carried out to investigate the fumonisin contamination in the products. based on their ingredients, the products were divided into seven groups: infant cereal designated as types a-d, corn meal, corn starch and instant cereal baby food. although certain infant food samples were free of fumonisin contamination (<20 microg kg(-1); corn starch and infant cereals of type a, b and d), contamination level ...200415370842
improving extraction of fumonisin mycotoxins from brazilian corn-based infant foods.the current aoac international methods for the determination of fumonisins have been validated for corn and cornflakes but have produced low recoveries and high variability when applied to processed corn products for infants. hence, an investigation was undertaken to improve the extraction efficiency for fumonisins by investigating the use of different extraction solvents. corn-based infant foods containing cornmeal, corn starch, and corn flour were purchased in the city of campinas, state of sa ...200312747696
accumulation of fumonisins b1 and b2 in freshly harvested brazilian commercial maize at three locations during two nonconsecutive seasons.fifty-six brazilian commercial maize cultivars were examined for fb1 and fb2 accumulation after two non-consecutive growing seasons. during the 94/95 growing season 35 cultivars were planted at three locations in the state of são paulo, brazil. all samples (total of 105) were contaminated (0.10 micro/g-6.58 microg/g fb1 and 0.04 microg/g-2.15 microg/g fb2). during the 97/98 growing season, 8 of the cultivars used during 94/95 and 21 others were replanted at the same locations. all 87 samples wer ...200212650599
mycoflora and fumonisin contamination in brazilian corn from sowing to harvest.the present study aimed to analyze the mycoflora and potential mycotoxin contamination of soil and corn samples collected at different plant maturity stages in capão bonito and ribeirão preto, two regions of the state of são paulo, brazil. in addition, the data obtained were correlated with the occurrence of wind-dispersed fungi and the predominant climatic conditions of the two regions studied. corn mycoflora profiles showed that fusarium verticillioides prevailed in 35% of the samples from cap ...200212059175
fumonisins b1 and b2 in brazilian corn-based food products.eighty-one samples of corn products were acquired from markets and supermarkets in the city of campinas, sp, brazil, and were analysed for fumonsins b1 and b2 (fb1 and fb2). forty samples (49%) were positive for fb1 (0.03-4.93 (micrograms/g) and 44 samples (54%) for fb2 (0.02-1.38 (micrograms/g). the samples, in order of decreasing contamination, were, corn meal (all contaminated, 0.56-4.93 (micrograms/g fb1), followed by degerminated corn (8/11 samples, nd-4.52 (micrograms/g fb1), corn flour (9 ...200011103273
evaluation of the black light test for screening aflatoxin-contaminated maize in the brazilian food industry.the results of the black light test for aflatoxin-contaminated maize carried out in a large food factory in the state of são paulo was evaluated against bi-directional thin layer chromatography (tlc) analysis for 286 samples of maize. all 286 samples were accepted by the black light test (< 7 fluorescent points), however, the results from tlc analysis showed that 96 samples were contaminated and 14 showed aflatoxin b1 contamination levels higher than 20 micrograms/kg. there were 14 false negativ ...19989602924
postharvest and stored corn in brazil: mycoflora interaction, abiotic factors and mycotoxin occurrence.the mycoflora of 130 samples of postharvest and stored corn was analysed throughout one year. the sample originated from riberirão preto, state of são paulo, brazil. the influences of abiotic factors (moisture content, relative humidity, temperature, rainfall) and mycotoxin occurrence were also verified. the isolation of the fungi was performed with potato dextrose agar. fungi were identified by using standard techniques. the determination of mycotoxins (aflatoxins, ochratoxin a, sterigmatocysti ...19957664921
natural occurrence of aflatoxins and zearalenone in maize in brazil. part ii.the levels of aflatoxins and zearalenone were determined in 328 samples of corn from the states of santa catarina, minas gerais, são paulo, paraná, rio grande do sul and espírito santo by thin-layer chromatography; the samples were obtained from april 1985 through to march 1986. in 12.3% of these samples aflatoxin b1 was detected in concentrations that varied from 10 to 900 micrograms/kg (ppb); 18 samples showed levels above those tolerated by brazilian legislation. zearalenone was found in 4.5% ...19892524411
[development of infestations of corcyra cephalonica (stainton, 1865) (lepidoptera, galleriidae) in some alimentary substrates (author's transl)].experiment to study the evolution of infestations of corcyra cephalonica in peeled peanuts, grain corn, wheat flour and grain coffee, were carried out in santos and in são paulo (state of são paulo, brazil). in the experimental conditions, more emergence resulted from peanuts followed by grain corn and third by wheat flour; a very small number of moths emerged from the grain coffee. the place did not interfere with the results.19751236043
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