1000 resultados para pinta preta dos citros


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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The experiment was carried out at Sao Manuel Experimental Farm, Agronomy College, São Paulo State University, Brazil, in a Dark-Red Latosol (loamy sand) to verify oat (Avena strigosa Schreber) rooting patterns under different plant populations (1,5 x 10(6) and 2.5 x 106 plants/ha) and row spacings (0.20 and 0.30 m.). Soil and roots were sampled 81 days after planting, at bloom stage. Cylindrical cores with 2.6 cm diameter were taken from soil depths of 0-10, 10-20, 20-40 and 40-60 cm. At the same time, plant canopies where also sampled to determine the dry weight. Soil analysis showed P to be concentrated in the upper 10 cm whereas the bases were uniform in the profile. There was a high root concentration in the 0-10 cm layer (9.9 to 13.0 cm/cm3 under the row and 10.0 to 11.5 cm/cm2 in the inter-row), which was not related to chemical characteristics of the soil. There was no effect of plant population or row spacing on oat root distribution or growth in the soil profile.

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The present work aims at defining the panicle and spikelet maturity of Avena strigosa Schreb. Four experiments were carried out under field conditions during 1989 (E1 and E2) and 1990 (E3 and E4) in Botucatu county, São Paulo State, Brazil. The sowings were made in 04.19.89 (E1) and 06.18.89 (E2). Maturity of panicle was evaluated by weekly (E1) or biweekly harvests (E2) beginning at total emergence of the panicle. In E3 and E4, sowing was made in 06.04.90 and each experiment had a single harvest date (E3 = 11.01.90 and E4 = 11.07.90). After harvest, the spikelets with similar stage of development were grouped and evaluated. Based on dry matter accumulation and germination percentage of the seeds, it was observed that the maturity of the seeds in the panicle was reached at 28 and 35 days after total emergence of the panicle in the April sowing, and between 24.5 and 28 days in the June sowing. During this period a few percentage of panicles not yet yellow became all yellow, the cariopsis at semi-hard stage became hard and moisture of the seeds dropped from 32% to 12%. The maturity of the seeds in the spikelet was reached when the glumes changed their color from yellowish to yellow, the lemma and palea changed from yellow with black strips to black, the cariopsis changed from farinaceous stage to semi-hard and the moisture content of the seeds changed from 40% to 25%.

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The objective of this research was to test the control of Brevipalpus phoenicis (Geijskes, 1939) by the hexythiazox and quinometionato products in citrus crop with and without adhesive spread and when submitted to artificial rain. The plants were sprayed at 2, 4, 8, 24 and 48 hours. When dried, the fruits were collected (eight/plants) and half of them were washed in laboratory with artificial rainfall on the basis of 30 mm/h during 15 minutes establishing the following treatments: T1 - hexythiazox + washing; T2 - hexythiazox + agral + washing; T3 - quinometionato + washing; T4 - quinometionato + agral + washing; T5 - control + agral + washing; T6 - hexythiazox; T7 - hexythiazox + agral; T8 - quinometionato; T9 - quinometionato + agral; T10 - control + agral. Thus, all the fruits were inoculated with ten females of B. phoenicis and five days later the mites alive were counted and eliminated. Approximately 15 days later the number of larvae alive were also counted. The results obtained allowed the following conclusions: a) the acaricides were efficient to control B. phoenicis; b) the rainfall (washing) did not alter the efficiency; c) the agral did not change the results.

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The present work aimed to define the field maturity of Avena strigosa Schreb seeds cv. Comum. Three experiments were carried out in field conditions during 1986, 1987 and 1989 in Botucatu, SP, Brazil. The sowings were made in May. The characteristics evaluated were: panicles and spikelet aspects, the weight of the dry matter of 100 seeds with and without glumes, the seed moisture, the percentage of germinated seeds (sum of normal + abnormal seedlings), the percentage of germination and vigor (first count of germination test). Based on the dry matter accumulation and the gemination percentage of the seeds, it was concluded that the field maturity of the seeds was reached around 28 and 3 5 days after 100% of panicles emergence of the field. At this stage, the field presented a few percentage of particles (+/- 20%) not yet all yellowish, with spikelets at semi-hard stage and the seeds with 20 to 30% of moisture.

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Citrus blackfly, Aleurocanthus woglumi Ashby, is a serious pest of citrus culture and other economically important fruit crops. It is a present quarantine pest or A2 maximum alert restricting trades with other regions free of its presence. Since the frst occurrence of the citrus blackfly in Belem in 2001 its dissemination was quickly to other States and regions of citrus production in Brazil. As an exotic pest, basic knowledge is scarce in order to establish the appropriate management to the insect in Brazil. Thus, the aim of the present study was to provide information about important aspects of A. woglumi, such as: history and geographical distribution, bioecology, host plants, appropriate control methods, among others, in order to provide subsidies for futures researches about the citrus blackfly in Brazil.

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The experiments were conducted during two years (1990/91 and 1992/93), to study the effects of the incorporation of bengal velvetbean and of residues on the development and yield of the winter bean crops. The trial was developed in experimental field at the Faculdade de Engenharia de Ilha Solteira, UNESP, located in Selvíria, MS, Brazil, in dark red latosol covered by savanna vegetation. It was concluded that: the incorporation of residues of corn or corn + bengal velvetbean or only bengal velvetbean had no effects on soil chemical characteristics, evaluated 80 days after the residues incorporation; in yield and bean crop development, no statistical differences were observed among treatments.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The construction of ecological life tables is a useful tool to understand the population dynamics of insects in the field. In this work, ecological life tables were developed for Phyllocnistis citrella (Stainton) in an orchard of Citrus sinensis situated in Santa Rita do Passa Quatro, Sao Paulo State, during 2002. The occurrence of generation overlay in the field was avoided by obtaining the eggs from infestation on young citrus plants (Citrus limonia) kept under controlled conditions. The samples were taken every other day and the number of live, dead, predated and parasitized individuals were recorded. The occurrence of arthropod predators was determined through visual search on the plants of the orchard. The key factors of mortality acting on P.citrella populations were: pupae parasitism caused by Ageniaspis citricola (Logvinovskaya), action of uncertain factors on prepupae and predation of 3rd-instar larvae. The most abundant arthropod predators belonged to the families Formicidae, Chrysopidae, Coccinellidae, Reduviidae e Araneae. In two of five generations of P. citrella, approximately 4% of A. citricola pupae were hyperparasitized by Galeopsomyia fausta (LaSalle) (Hymenoptera: Eulophidae).

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Incluye Bibliografía

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The high cost allied to the difficulty in the acquisition of the ammonium nitrate has been taking the accomplishment of works looking for an alternative for the substitution of this source of nitrogen. It was aimed at to study the technical viability of the substitution of the ammonium nitrate for urea, as source of nitrogen in the culture media for the blackberry in vitro cv. Tupy (Rubus sp). Nodal segments were used, already established in vitro, were inoculated in culture media MS and 50% MS, added of 1.0 mg. dm-3 of BAP, solidified with 6 g.dm-3 of agar, pH was adjusted for 5,8 and sterilized to 121 °C and 0,1 MPa for 20 min. The treatments consisted of the substitution of 0; 20; 40; 60; 80 and 100% of NH4NO3 for urea, and the swinging of nitrogen supplied by the culture media MS it was not altered. The explants were maintained by 60 days in growth room with temperature of 27±1 °C, photoperiod of 16 h and luminous intensity of 32 mmol m'2 s'1. The experiment was arranged in a completely randomized design, in factorial (6 x 2) using four repetitions with 16 plants each one. From the obtained results it can be concluded that the urea doesn't substitute NH 4NO3 in the culture media MS as nitrogen source in the culture vitro of blackberry.

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The objective of this work was to analyze the consumption, electric energy cost, and economic results of irrigated citrus (Citrus sinensis). The treatments consisted of a dripping irrigation system with one and two lateral distribution lines, a micro sprinkler irrigation system and a treatment without irrigation. For each irrigation system, three water depths were used: 100%, 75% and 50% of Etc (citrus evapotranspiration). The electric energy cost for two tariff groups, Group A and Group B, was studied. For Group A, the expenses with energy were determined for the Conventional Binomial Structure tariff, the Hour-seasonal tariff (green and blue) and the special tariff for nocturnal irrigation. The kWh cost for the tariff systems were obtained from the website of CPFL (São Paulo State Power and Light Company, Brazil). The best relation between the electric energy consumption (kWh.ha -1) and productivity (t.ha -1) occurred in the treatment irrigated with 50% of the Etc. The irrigated treatments increased productivity. The biggest productivity was observed in the irrigation treatments with 50% of the Etc when compared to the ones with 100% of the Etc. The blue and green Hour-seasonal tariff system of Group A (nocturnal irrigation) was the best option. A biggest economic turnover occurred in the treatments irrigated with 50% of the Etc.

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Diospyros ebenaster, originária do México e América Central, família Ebenaceae, é conhecida como sapota-preta. Os frutos podem ser consumidos in natura ou em sucos, como fonte de vitamina C. O objetivo deste trabalho foi caracterizar a morfologia do fruto, da semente e do processo germinativo da espécie. Os frutos foram caracterizados quanto à coloração, textura, consistência e teor de água no pericarpo, deiscência, massa, partes constituintes e dimensões. Para as sementes considerou-se: Massa, coloração, textura e consistência do tegumento, forma, presença e tipo de tecido de reserva e tipo, coloração, forma e posição do embrião. A descrição das plântulas foi realizada a partir da emissão da raiz primária até a expansão dos primeiros eófilos e início de fenecimento dos cotilédones. O fruto é carnoso, indeiscente, do tipo baga, polispérmico, globoso e achatado nos pólos. O epicarpo é liso, delgado e esverdeado. O comprimento médio dos frutos é 8,8 cm, o diâmetro médio 8,6 cm e a massa de 263 g. As sementes apresentam tegumento liso e cor castanho-médio. A massa de 100 sementes é 100,6 g. O comprimento médio das sementes é 2,2 cm, com 1,3 cm de largura. Possuem endosperma branco-Transparente e oleaginoso. O embrião é esbranquiçado e a germinação é epígea.

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The success in weed control by using straw depends on the management time, straw quality and quantity. The objective of this research was to evaluate the suppressor effect of black-oats and millet straw cover on the incidence of weeds and on the productivity of the soybean crop. The experiment was carried out during the years 2006 and 2007, in an area from the Farm of Education, Research and Production of FCAV-UNESP, Jaboticabal Campus, in a completely randomized block design, with four replications. Treatments consisted of different types of black oats and pearl millet straw management before soybean seeding (without management, obtained by machine cut, desiccated using glyphosate desiccation and with paraquat) and different periods of straw deposition (0, 15, 30 e 60 days before soybean seeding). The weed population and the characteristics of soybean growth and production were evaluated. The deposition of black oats and pearl millet straw provided reductions in weed density and dry mass, and this effect was more effective when the deposition occurred until 15 days prior to soybean seeding. The suppressor effect of black oats straw was more pronounced than that of pearl millet straw, regardless of the drying method, although the millet had a greater dry matter production. No significant differences were found between the drying methods and the straw effectiveness.