Novas tecnologias para o controle da giberela do trigo na safra 2014 no sudoeste do Paraná

The work consists in wheat production system and the evolution of damage caused by wheat scab. The study considers the lack of resistant cultivars to the disease, the low efficiency of chemical control and the presence of mycotoxins in grains. The study aimed to confirm the effectiveness of fungicides prothioconazole and metconazole; prove the bar deposition efficiency with nozzles directed jets the side of the ear resulting in full coverage of trapped anthers; prove the viability of using a warning system (application after the start of flowering before the onset of rains provided for future 24-48 hours and try to improve the efficiency in controlling scab. The experiment was conducted in the experimental field of Technological University Federal do Paraná in the city of Pato Branco, Paraná, conducted in two seasons, the first established on May 6, 2014 and the second on 21 May 2014. It was used to cultivate Amethyst field of OR Improvement seeds, . Passo Fundo, Rio Grande do Sul Treatments consisted of a control without fungicide application and one and two applications of prothioconazole + 17.5% trifloxystrobin (Fox) 500 ml / ha; metconazole 8.0% + pyraclostrobin 13% ( Opera Ultra) 750 mL / ha In the evaluation, second season, metconazole + pyraclostrobin with two application statistically was the treatment that showed a lower incidence in spikes reducing from 100 to 63.3%;. metconazole + pyraclostrobin performed better also in reducing the incidence of spikelets, 80.3% to 34.7%; the control ears had better results in the second season with two applications of metconazole + pyraclostrobin; in spikelets, in his first season, metconazole + pyraclostrobin with two application resulted in better control with 67%; with two applications of metconazole + pyraclostrobin gave the highest yield even under climatic conditions favorable to disease; metconazole + pyraclostrobin in both seasons showed superior efficiency in controlling FHB giving greater weight gain; with two application of both fungicides, the hectoliter weight was 81 and 79, respectively, each fungicide; the application of fungicides was made in advance of expected rain, occurring seven days of rain and a total volume of 85,2mm the first time, and 16 days of rain and an accumulation of 400 mm in the second period; the test efficiency can be confirmed when the direction of the spray jets launched wings coupled in double nozzle bodies perpendicular to the target upright reaches the sides of the spike. The metconazole + pyraclostrobin proved the most effective fungicide against the prothioconazole + trifloxystrobin in wheat scab control in the 2014 harvest.

Quitosana na indução de resistência ao tombamento de plântulas de espécies olerícolas e no controle de fitopatógenos in vitro

Induction of resistance is defined as the activation of a state of resistance against diseases which is induced systemically in plants by the use of biotic or abiotic agents without any modification of the plant genome, occurring non-specific way, by activating genes coding for various plant defense responses. Chitosan is a polymer derived from the deacetylation of chitin, which is found in large quantities in crustacean shell, and studied with the potential to control plant pathogens, both by its direct fungistatic action, as the ability to induce protection of plants, indicating the presence of molecules of elicitoras characteristics. Three experiments with objective of evaluating the potential of chitosan in the seedling resistance induction were developed, beet (Beta vulgaris) seeds, cucumber (Cucumis sativus) seeds and tomato (Solanum lycopersicum) seeds, and the control of Fusarium sp., Rhizoctonia solani K¨uhn e Pythium sp. in vitro conditions. The experimental design was completely randomized, with four replications. Beet seeds, tomato and cucumber were submerged in chitosan solution for 20 minutes, in concentrations of 0.25, 0.5, 1 and 2% in the control and distilled water. Seeds were sown in trays containing Plantmax Florestalr substrate sterilized and inoculated with Fusarium sp., Rhizoctonia solani K¨unh and Pythium sp., respectively for the three cultures. The experiment was conducted for 14 days in growth chamber with controlled temperature (25 C 2 C), light (12 hour photoperiod) and humidity (70% 10%). The evaluations were seed emergency, seedling damping-off, seedling length, fresh weight and activity of the enzymes phenylalanine amˆonia-liase (PAL), chitinase and b-1,3-glucanase. It was also rated the mycelial growth of Fusarium sp., Pythium sp. and R. solani on P.D.A. (Potato-Dextrose and Agar) culture medium containing chitosan at the same concentrations evaluated in seeds. For beet growing, seed treatment with chitosan presented higher emergence and the length of the seedlings, and reduced the percentage of tipping. Treatment with chitosan activated the systemic acquired resistance with expression of chitinase and b-1,3-glucanase enzymes. For the tomato crop in chitosan concentration of 0.25% favored the emergency of seedlings, reduced the incidence of tipping and activated the PAL enzymes, chitinase and b-1,3-glucanase. In cucumber on the concentration of up 0.5% favored seedlings emergence and reduces the incidence of tipping. Chitosan activated the PAL enzymes and b-1,3-glucanase. Chitosan also presented fungistatic action on the initial growth of Pythium sp. and R. solani in vitro conditions, however, such action did not prevail until the end of the experiment. To Fusarium sp. the concentration of chitosan resulted in the reduction of mycelial growth in vitro.

Potencial do óleo de Aloysia citriodora Palau no controle de fitopatógenos e na indução de resistência ao tombamento de plântulas de feijão, pepino e beterraba

The crops are affected by pests and diseases that decrease productivity. Among them are the damping off of seedlings that can occur in pre and post-emergence. In bean crops, cucumber and beet these diseases occur, being caused by various pathogens, especialy fitopathogenic fungi. Several measures are used for the controle of such diseases, among them, is the chemical seed treatment fungicides. However, society has become increasingly concerned about the quality and food and environmental contamination, generation a growting search for sensitive products to humans and the environment. The use of essential oils to control plant pathogens is an example of alternative tested by science in the search for less aggressive technologies. This study aimed to evaluate the efficiency of the use of essential oil Aloysia citriodora, in control of pathogens causing damping off in beans, cucumber and beet. This thesis was divided in four chapters, the introductory first, and the other addressing the control of Pythium sp. in beans, Sclerotinia sclerotiorum on cucumber, and Fusarium sp. on beet. The methodology consisted of four experiments in each pathosystem, with all the work done at the Federal Technological University of Parana, Campus Dois Vizinhos. In the first experiment evaluated the fungistatic and fungicidal effect of the essential oil of A. citriodora on PDA in vitro in mycelial growth of pathogens studied. In the second experiment evaluated the in vitro effect of essential oil concentrations of A. citriodora in BD medium on microscope slides, on the germination of sporangia Pythium sp. and conidia Fusarium sp., and in Petri dishes with PDA medium, the sclerotia germination speed index of S. sclerotiorum. In the third experiment, we evaluated in germination test in paper roll (PR), the phytotoxic effect or not the use of essential oil concentrations of A. citriodora in dry bean seed, cucumber and beet. The variables used to assess this experiment were the germination percentage, mediun green mass per plant and average length of seedlings. In the fourth experiment we assessed the effect of treating bean seeds, cucumber and beet with essential oil contents of A. citriodora, seeds in their subsequent substrates contamined with pathogens studied, Pythium sp., S. sclerotiorum and Fusarium sp. In this experiment we used the following variables: percentage of emergence, percentage of post-emergence damping off, green average mass per plant, average length per plant and biochemical analyzes. The biochemistry of plant tissues evaluated were as follows: protein content, enzymatic activities of peroxidases, phenylalanine ammonia-liase (PAL), chitinases and β-1,3-glucanases. The in vitro results show that the essential oil has fungistatic and fungicidal effect on mycelial growth, on sporangia germination, conidia and sclerotia of the pathogens studied in this work, wich may be related to its major components, citral and limonene. The oil also exhibits low phytotoxicity to seeds of the species studied, only in beans decreases germination in most studied dosage (0,25%), cucumber also in the higher dosage (0,25%) reduce the length of seedlings, and beet there were no negative effects to the seedlings. In the test in substrate contaminated with the pathogens, the use of essential oil: increased germination and decreased post emergence damping off of beans seedlings; at a concentration of 0,0625% decreases post emergence damping off in cucumber. In biochemical analyzes found an increase in the enzymatic activity of peroxidases and β-1,3-glucanases on beans, and glucanases on cucumber, and increased enzyme activity of peroxidases on beet, showing action in resistance induction at damping off.

Destino no ambiente e comportamento agronômico de atrazina em resposta a doses e níveis de palha de espécies de cobertura de solo

The use of cover crops is a fundamental strategy to the weed management in Southern Brazil. In highly infested areas, the herbicides use is increasing, which increases the costs of the crops production as well as the environmental contamination. Oat and velvet bean plants havecontrasting characteristics regarding to residues decomposition speed and the capacity to immobilize Nitrogen in the soil, providing distinct results of weeds suppression throughout the time, and therefore, requiring distinct management strategies before, during, and after the corn crop establishment. The general objective of the experiment was to evaluate the environmental dynamics of the herbicide atrazine, the corn grain yield, and the efficiency of the weed control, considering areas with distinct history regarding the use of mulching, levels of straw and rates of atrazine. For this, the experiment was carried out in two parts: in the first part, two trials with the corn crop were established, one using oat and the other using velvet bean as cover crops. The experimental design used for both field trials was randomized complete blocks arrangement with four replications. The factor A was constituted by four levels of straw (0; 0.75x; 1.5x; 3x) and the factor B was constituted by four rates of the herbicide atrazine (0; 2100; 4200; 8400 g a i. ha-1). Soil samples were collected for greenhouse trialsto determine the persistence. Atrazine leaching evaluation was performed by chromatography using samples collected over the soil profile.In the field, the weed density, the fresh and dry weight and the yield of the corn were evaluated. In the greenhouse trials, the main variables evaluated were plant height and injury caused by the herbicide toxicity. In the second part, soils with distinct covering history were sampled, and the mineralization and sorption studies, both with 14C-atrazine, were conducted in the laboratory. The experimental design was randomized complete blocks arrangement with four replications. The results from the field experiment show that the high levels of straw above ground, isolated, were not efficient to control completely the weeds, and that high levels of velvet bean`s straw decreased the corn potential yield. The greenhouse trials showed that high levels of oat straw prevent the scape of atrazine to soil, this effect of oat straw upon the herbicide availability on soil was detected up to 12 days after spraying. The half-life of atrazine sprayed over oat straw varied from 7 to 14 days after spraying, while the half-life of atrazine sprayed over velvet bean varied from 5 to 14 days after spraying. Increasing oat straw levels presents the capacity to reduce the lixiviation of atrazine in the soil profile, however, this effect was not verified when using velvet bean straw, because the herbicide was not detected in the soil profile, at 21 days after spraying. The chromatographic analysis indicate thatthe atrazine concentrates closer to the soil surface regardless of amount of straw, not being detected deeper than 8 cm in the soil. The accumulated mineralization of 14C-arazine sprayed over V. sativa is superior if compared to soils with S. cereale or non-covered soils. The sorption coefficient of atrazine is superior when sprayed over straw than over the soil.

Chorume de suíno no controle da rizoctoniose em beterraba

The fungus Rhizoctonia solani is a soil borne pathogen that causes damage to various crops. The chemical control, when managed incorrectly, can be harmful to the environment, which makes the study of alternative control important. This study aimed to evaluate the ability of different doses of Liquid swine manure (LSM), with and without the retention of gases, at different soil pH levels, to control R. solani in beet. An inoculum of the fungus R. solani was on rice grains, which had been previously sterilised. The experiments were set up in a greenhouse in a completely randomised block design, arranged in a three-factor 2 x 2 x 5 scheme, comprising of soil pH levels (4.8 and 7.2) x with and without gas retention x LSM dose (0, 5, 10, 15 and 20%), with four replications per treatment. To setup the experiments, 4 kg of soil of each pH level were packed separately into plastic bags. Subsequently, the soil of each bag was infested with 15 g of fungus inoculum/kg of soil, and moistened as necessary. After seven days of infestation of the soil with the pathogen the different doses of LSM were incorporated separately into the bags, the bags designated as the gas retention treatment were closed, while those designated as the gas release treatment were left open. After seven days, part of the soil from each bag was packed separately into 16 cells of 128 cell Styrofoam trays, which were then seeded with two beet seeds per cell. The other part of the soil was placed in 2 litre pots, to conduct the quantification of microbial activity, through the method of CO2 release, 21 days after the experiment was setup. Seedling emergence and damping-off evaluations were performed daily for 21 days consecutively. The data was submitted to analysis of variance, and when significant were submitted to regression analysis or Tukey at 5% probability of error. The experiments were repeated twice. According to the results obtained, there was a suppressive effect of LSM on R. solani. For the variable emergence, the 10% dose of LSM resulted in the largest number of emerging plants in the two soil pH levels studied, whether or not gas was retained. Seedling dampingoff decreased with increasing volumes of LSM incorporated into the soil. The soil with the pH level of 7.2 presented less seedling damping-off than the soil with a pH level of 4.8. The retention of gases provided greater control of R. solani in the higher LSM doses and in soil with a pH level of 7.2. Also noted in this study that there was a significant increase in microbial activity with increasing doses of LSM when applied to soil with pH levels of 4.8 and 7.2. Based on these results, it was concluded that the 10% dose of LSM provided the best control of R. solani without harming seedling emergence.