Aplicação de nitrogênio no solo e pulverização foliar com ácido giberélico e uréia em Setaria anceps Stapf cv. Kazungula

O objetivo do experimento foi verificar o efeito do nitrogénio no solo, parcelado de diferentes formas e aplicado durante o período de "verão", combinado com pulverização foliar de ureia e/ou ácido giberélico, sobre a produção e qualidade de Setaria anceps Stapf cv. Kazungula. O nitrogênio (60 kg/ha/ano) foi aplicado segundo quatro formas de parcelamento: Testemunha (sem nitrogênio), N20M40 (20 kg/ha de N em novembro + 40 kg/ha de N em março), N30M30 (30 kg/ha de N em novembro + 30 kg/ha de N em março), F20M40 (20 kg/ha de N em fevereiro + 40 kg/ha de N em março). No início do período de "inverno" foram aplicados os quatro tipos de pulverizações foliares: Testemunha (sem ácido giberélico ou uréia), uréia a 2%, ácido giberélico a 50 ppm e uréia a 2% + ácido giberélico a 50 ppm. Os resultados revelaram que o parcelamento do nitrogénio no solo não influiu no aumento da produção de matéria seca do capim setária no período de "verão", apesar de proporcionar um incremento da mesma no corte de "inverno". Observou-se, ainda, uma boa distribuição da produção de matéria seca entre "verão" e "inverno", apresentando essa última estação 34,52% da produção total anual, em média. Os diferentes tipos de pulverização não influíram significativamente sobre a produção de matéria seca e a composição química bromatológica da forrageira no período de "inverno".

Mancha-foliar-de-Phyllosticta em gengibre. caracterização cultural do patógeno e efeito de tratamentos químicos no controle da doença em Morretes, Estado do Paraná

The objectives of this work were to determine the micelial growth curve of the pathogen and the sensitivity to some fungicides potencially efficient to disease control. The optimum temperature range for micelial growth of Phyllosticta sp, was between 25 and 27.5 degrees C. The maximum and minimum temperatures for micelial growth were 32.5 degrees C and 10 degrees C. Temperatures of 5 and 35 degrees C completely inhibited the growth of the isolates. Total inhibition of the micelial growth was observed with captan and mancozeb (1000 mg a.i./ml) and triadimenol (100 mg a.i./ml). Partial reduction of the micelial growth was observed with iprodione, methyl tiofanate and chlorothalonil until 1.000 mg/ml. The chemical control of PLS was studied in a commercial area of ginger ''Gigante'', in Morretes, PR, where 18 sprays were carried out, with a break of 7 to 10 days, from December to April. The highest reduction of the area under the disease progress curve standardized (AUDPCs) was observed with the spray of chlorothalonil. With the application of dithianon, cupper oxychloride, folpet, mancozeb and captan it was observed AUDPCs between 15.05 and 18.61 lesions/leaf. Iprodione, benomyl, triadimenol and methyl tiofanate did not control the disease (AUDPCs between 20.03 and 25.04 lesions/leaf). The AUDPCs in the check plot was 35.88 lesions/leaf. There was no significant difference of vigor and of ginger yield between fungicide treatments. The cupper oxichloride was phytotoxic to ginger.

Potencial alelopático de Ipomoea fistulosa sobre a germinação de alface e tomate

The objective of the present research was to determine the allelopathic potential of Ipomoea fistulosa plants on germination and growth of seedlings. In laboratory, lettuce and tomato seeds were placed to germinate in the presence of water or Ipomoea fistulosa leaf extract, in the concentrations of 5, 10 e 15% (p/v). In greenhouse, seeds were placed to germinate in trays containing Plantmax (R) substrate and Plantmax (R) substrate + Ipomoea fistulosa dry leaf residue, at 3% (w/w). The aqueous extract inhibited germination, raised the mean germination time of the seeds and reduced the radicle and hypocotyl growth in all used concentrations. In greenhouse, the plant height, leaf number, and dry mass accumulation also were reduced in the presence of the leaf residue in the substrate. The results suggest the presence of allelochemicals in Ipomoea fistulosa and demonstrate the highest sensitivity of lettuce that tomato to these compounds.

Potencial alelopático e levantamento do banco natural de sementes sob a copa de Copaifera langsdorffii Desf

the aim of this study was to evaluate the allelopathic effect of soil samples collected under the canopies of three specimens of Copaifera langsdorffii the germination of Lactuca sativa and survey the natural seed bank according to seasonality. To test the allelopathic effect was carried experiments of pre and post-emergence with seeds of L. sativa and to quantify the stock of seeds, soil samples were collected from three specimens at three distances from the stem (1, 2 and 3 m) and at three depths (0-5, 5-10 and 10-15cm) in the region of savanna in the dry and wet seasons. The samples tested in bioassay of pre-emergence no significant influence on germinability, mean germination time and mean germination speed, but showed a difference in the synchronism of germination, these data were independent of sampling station. In test for post-emergence was observed statistical difference in the parameters evaluate (length of primary roots and hypocotyls) in both seasons. To quantify the natural seed bank were macroscopic analysis of each soil sample with the help of stereoscopic microscope. The analysis of the natural seed bank showed a larger number of seeds in the 0-5cm and in distance of 2m for both seasons. The results suggest the presence of allelochemical substances in soil samples collected under the canopy of Copaifera langsdorffii.

Effect of foliar and substrate fertilization on lady palm seedling growth and development

Lady palm, [Rhapis excelsa (Thunberg) Henry ex. Rehder] is one of the most cultivated ornamental palms in the world, for use as a vase plant or in shaded landscapes. Because limited information exists on lady palm response to fertilizers, the objective of this study was to evaluate the effect of different types of fertilization and substrates on lady palm seedling growth and development. Three year old lady palms were planted in 8-L pots, filled with a mix of soil, manure, and sand 1:1:1 (v:v:v), placed under a 50% shade, and irrigated with microspray. Treatments were substrate fertilization with 500 g P(2)O(5) and 100 g K(2)O per m(3); fertilization with 1.8 kg of P(2)O(5) (simple superphosphate) per m3; 50 g of nitrogen (N), P(2)O(5), and K(2)O of a granulated fertilizer (10:10:10) per m(3), control (without fertilization), and a foliar fertilization in addition to these treatments using the commercial product Biofert (8:9:9). Treatments were replicated four times in a randomized block design. Each treatment plot consisted of four plants. Data were collected at 140, 170, 200, 230, 260, and 290 days after transplanting (DAT) for plant heights, stem diameter at substrate level, number of leaves, shoots, and canopy, roots fresh and dry matter samples were harvest at 290 days. Foliar fertilization resulted in significantly greater plant height in a 140, 120, 200, and 230 DAT and plant diameter on the 140, 260, and 290 DAT. There was interaction among factors for number of leaves with fertilization based on P(2)O(5) and K(2)O when leaf fertilizer was added that resulted in a greater number of leaves.

Cultivares de trigo submetidas a déficit hídrico no início do florescimento, em casa de vegetação

The water restriction can damage the performance of crops, especially in the flowering period. Thus, the aim of this research was to evaluate the response of genotypes of wheat submitted to water deficit in the beginning of flowering. The experiment was conducted in greenhouse, in a completely randomized design, in factorial scheme 3 x 2, with five replications. The factors studied were: three wheat cultivars (Coodetec (CD) 105, 108 and 111) and 2 irrigation managements (with and without imposition of water deficit). During the period of water deficit imposition, gravimetric soil moisture and the relative content of water in leaf were evaluated, while at the moment of rehydration the biometric variables were determined. At the end of the crop cycle the components of production were evaluated. Reduction was found in the gravimetric soil moisture, in the relative levels of water and in all biometric variables, in function of the water deficit. The grain production showed difference only among the water regimes, in which the cultivar CD 111 is more efficient in the maintenance of the productive potential in conditions of water deficit, through the quick recovery in the relative content of water in leaves.

Potencial mirmecológico na vetoração mecânica de helmintos em gatis

Vector potential of ants in mechanic dissemination of helminthes in a cat rescue center was analyzed in this study. Ants walking over cat's food and feces were collected and conditioned in distilled water. Cat feces were collected too. Ants were identified and the water where they were conditioned was observed on optic microscope. It was made the simple sedimentation technique to analyze feces. The results show that ants species Pheidole and Paratrechina can be potential vectors of nematode eggs, mainly Ascaridida, Toxocaridae.

Estresse hídrico induzido por manitol em cultivares de algodão

The main goat of this work was to evaluate the effects induced by mannitol- water stress in the initial growing of cotton plants. The experiment was conducted as a completely randomized design, in factorial design 4 x 5, with 3 replications. Treatments were generated by the combination of four cotton cultivars (LD CV Frego; LD CV 02; FMT 701 and IAC 25) and five levels of water stress (0; -0.3; -0.6, -0.9 and -1.2MPa), obtained with mannitol solutions. Water potentials of -0.9 MPa reduced significantly the rate of cotton plants growth. The decrease of the water potential reduced the production of dry mass of the aerial part of all cultivars and increased the production of root dry mass on -0.6MPa potential. LD CV 02 cultivar exhibited a superior performance under water stress.

Potencial alelopático de extrato etanólico de Anadenanthera macrocarpa e Astronium graveolens

The objective of this study was to evaluate the allelophatic potential ethanol extract of leaves of Anadenanthera macrocarpa (Benth.) Brenan (angico) and Astronium graveolens Jacq (aroeira) on the biomonitor germination of Brassica chinensis (Malaysia's cabbage) and Lactuca sativa (lettuce). For the test of allelopathy was the bioassay of germination of B. chinensis and L. sativa using solutions of ethanol extracts in different concentrations (5, 10 and 20 mg / mL) with continuous light for 11 days. The experimental and control groups were divided into the Petri dish containing 50 seeds of B. chinensis and L. sativa each. Were performed six replicates for each concentration of extract of leaves of A. macrocarpa and A. graveolens and the negative control (water). The rolling action of the treatments was performed by quantitative observation and monitoring of germination every six hours. The results show that the ethanol extract of A. macrocarpa and A. graveolens presents allelopathic potential, regardless of the concentration used, but with answers dose-dependent, and thus able to interfere directly in germination, average speed and time of germination biomonitor of B. chinensis and L. sativa.

Atividade da enzima redutase do nitrato e teores de prolina livre em raízes de cana-de-açúcar sob os estresses hídrico e ácido no solo

The aim of this work was evaluate the physiological indicators of association between water deficiency and soil acidity, by determining the nitrate reductase activity, the levels of free proline and initial growth of the root system of seedlings of sugarcane cv. IAC91-5155. After 30 days, the seedlings were transferred to plastic pots with 12 dm3 of dystrophic alic Red Latosol (Oxisol) and submitted to association of three treatments of water availability: no stress (70%), moderate stress (55%) and severe stress (40%), in according with field capacity and three acidity treatments: no stress (55%), moderate stress (33%) and severe stress (23%), considering the base saturation. The experimental design was that of random blocks under factorial scheme of 3x3, with four replicates. After 60 days under the stress association, the levels of free proline, the nitrate reductase activity and the growth of the sugarcane roots system were evaluated in seedlings of sugarcane. The nitrate reductase enzyme activity can be considered a physiological indicator of the effect of the association of acid and water stress in moderate conditions in soil, while the free proline can be considered physiological indicator to both stress in severe conditions. Water deficiency increasing reduced growth of sugarcane roots.

Relação entre o fluxo luminoso interceptado em diferentes épocas no índice de área foliar de diferentes forrageiras

The objective was to evaluate the leaf area index of six different grasses. The experiment was installed at the Instituto Federal de Tecnologia e Educacao of Uberaba, using a randomized block design with split plots in time. The plots were sown: Brachiaria decumbens cv. Basilisk, Brachiaria brizantha cv. Marandu, Panicum maximum cv. Mombasa, Panicum maximum cv. Tanzania, Brachiaria brizantha cv. Xaraes, Cynodon dactylon hb. Tifton and the plots, ten seasons of evaluation in 10 x 6 factorial arrangement with four replications. Rates of leaf area of each forage at different times of year were evaluated. Compared to other forage species, Panicum maximum had a higher leaf area index when subjected to periodic fertilization and irrigation. Only in the late fall Brachiaria Xaraes IAF had increased, but did not differ significantly from the others.

Efeitos do potencial alelopático de três leguminosas forrageiras sobre três invasoras de pastagens

Bioassays were carried out to identify and characterize the allelopathic potential effects of forage legumes leucena (Leucaena leucocephala), mineirão (Stylosanthes guianensis cv. Mineirão) and calopogônio (Calopogonium mucunoides) on germination and radicle elongation of the pasture weeds desmódio (Desmodium adscendens), guanxuma (Sida rhombifolia) and assa-peixe (Vernonia polyanthes). Aqueous seeds and shoot extracts were prepared in a concentration of 10% (w/v). The pH and osmotic potential were measured in each extract. The effects of the osmotic potential on the results were calculated considering the regression equations adjusted to the variations of osmotic potential in each parameter and the osmotic potential of the extracts. The results showed that the pH did not constitute in a source of variation of the results. The donor species indicated allelopathic potential that varied in function of donor and receiver species and part of the donor plant. The aqueous shoot extract of mineirão and calopogônio showed inhibition potential higher than the extract from seeds, while for leucena the effects more evident were obtained with the extract from seeds. Comparatively, the radicle elongation was a more sensitive indicator than germination to the effects of the extracts.The receiver species assa-peixe was the less sensitive to the effects of the extract.

Effect of constituents of the foliar wax of Didymopanax vinosum on the foraging activity of the leaf-cutting ant Atta sexdens rubropilosa

Leaf epicuticular waxes may affect substrate selection by leaf-cutting ants, and host recognition by several phytophagous insects. The influence of the crude epicuticular wax of Didymopanax vinosum E. March. (Araliaceae), and its major constituents lupeol and free primary alcohols, on substrate selection by the leaf-cutting ant Atta sexdens rubropilosa Forel, was investigated. Two ant colonies were used in laboratory bioassays. Corn flakes (zea) were impregnated with chloroform solutions of the substances being tested and fed to the adults. One of the colonies gave results, in most of the tests, not significantly different from the controls. The other colony, however, discriminated against the crude wax, a strong deterrent effect being observed from the first of a series of eight trials. The same colony was able to discriminate against lupeol after the second trial. The fraction of primary n-alcohols (22% C28, 66% C30 and 12% C32) deterred feeding only after the fifth trial. The results demonstrate that some constituents of epicuticular waxes may deter the foraging activity of A. sexdens rubropilosa, depending, however, on the colony under observation. It is suggested that lupeol, of the foliar wax of D. vinosum, is an important deterrent to leaf-cutting ants, although with less pronounced effects than those observed in tests with the crude wax.

Uso da adubação foliar nitrogenada e potássica no algodoeiro

The present work was conducted in Selvíria county (MS-Brazil), in the agricultural year of 1998/99, for evaluating nitrogen and potassium foliar application to supplement sowing fertilization on cotton (IAC 22) crop. A randomized complete block design with 13 treatments and four replications was used. The treatments were constituted by a control (without foliar application) and nitrogen and/or potassium foliar applications two, four, six or eight weeks after beginning of flowering. The urea was used as source of N and potassium chloride as source of K. Urea in the concentration of 10% and potassium chloride at 4% were applied at a rate of 250 L.ha-1. Height of plants, nodule number, number of reproductive branches, boll per plant, 30 boll mass, yield and fiber percentage were evaluated. It is concluded that the N doses increased the yield and decreased the fiber percentage. There was no evaluated response to the application of K or NK.

Efeitos de sistemas de preparo do solo no potencial matricial de um Latossolo Vermelho (Oxisol)

The present work aimed to investigate which was the soil tillage system that better fits for conditions of intensive agriculture, on the region of Selviria-MS. The main objective of this paper was to study the conservation and availability of water in the soil profile. In order to evaluate the soil matric potential in field conditions, readings were accomplished, using tensiometers with a mercury gauger. Matric potential was measured at 0.10 m depth, during the vegetative period of Triticum aestivum L. and at four depths 0.10; 0.20; 0.30 e 0.40 m during the vegetative period of Phaseolus vulgaris L. The study areas were located in the municipal district of Selviria, MS, Brazil. The used experimental set-up was entirely random designed, with treatments disposed in strips; three treatments and four repetitions were used. In the different treatments, soil matric potential was determined. Result allow to conclude that the water matric potential was highest for no-tillage and minimum tillage; however, it was also shown that these two tillage systems, allowed to conserve more water in the soil, when compared to the conventional tillage. In the last cycle of the Phaseolus vulgaris L. crop, no-tillage presented smaller storage of water in the soil, compared to the minimum tillage.