The objective of this study was to develop and validate a diagrammatic scale to evaluate the severity of spots on maize leaves caused by the fungus Diplodia macrospora. Severity ranged between the minimal (0.5%) and maximal (55%) limits of disease severity, and intermediate severity levels were defined according to the "Weber-Fechner stimulus response law". The proposed scale describes six levels of severity based on how much of the leaf is affected: 0.5%, 3%, 8%, 23%, 36%, and 55%. Validation was carried out by eight evaluators, four inexperienced and four experienced. They estimated the severity of disease in 60 maize leaves, with and without the proposed diagrammatic scale. A relationship was shown by regression analysis between estimated and actual severity, with and without the use of the scale. When both inexperienced and experienced evaluators used the scale, they were able to estimate disease severity more accurately and precisely.
The aims of the study were to evaluate the control of botrytis in the soybean stem, spraying homeopathic solutions of Sulphur and Nosode of Macrophomina phaseolina in the dynamizations 6, 12, 24, 36 and 48CH. As additional treatment, we used distilled water and hydroalcoholic solution at 30% ethanol. In vitro tests were performed so as to analyze the number of micro-sclerotia and mycelial growth of the fungi, and in vivo tests to track the progress of the botrytis stem and the size of the lesion. The experimental design was in randomized blocks, with five replications. For the area under the mycelial growth curve (AUMGC) in the first test, there was no significant effect of Sulphur and Nosode of M. phaseolina. In vivo studies, comparing Sulphur with the control treatment, showed a reduction of 14 and 15% for the dynamizations of 12 and 48 CH, respectively. For the amount of micro-sclerotia of M. phaseolina, in the first test, Sulphur showed a reduction of up to 50%; Nosode of M. phaseolina showed no significant reduction of micro-sclerotia. In the second test, Nosode was not significant while Sulphur caused a reduction of up to 33%. For area under the disease progress curve (AUDPC), in both trials, the drugs proved to be ineffective. These results indicate the potential of these homeopathic remedies in controlling the fungus, M. phaseolina.
This review article has aimed at environment and impact of different pollutants, define, classify, analyze and cite methods of remediation according to Brazilian environmental legislation. Concerns about the preservation of the environment is extensively debated nowadays, with a view mainly to the production of effluents in agriculture, toxic metals, emerging pollutants and excessive use of agrochemicals. However, some impacts are necessary to meet the needs of economic development and social to ensure they are carried out rationally. Furthermore, application of remediation methods reduce the impact of these pollutants as small as possible. In this sense, the environment's definition, the main current impacts, the size and consequences of these and some remediation methods, as well as Brazilian environmental legislation will be addressed.
Bean common bacterial blight reduces crop productivity and is difficult to control. However, biological control by yeast can be an efficient complementary measure in management. The objective was to evaluate the ability of Rhodotorula glutinis and Sporidiobolus johnsonii to reduce the severity of bean common bacterial blight. The cultivar used was IAPAR Tuiuiú. The first experiment was sown in March and repeated in October, in a 4 × 3 factorial scheme (zero, one, two and three applications and three treatments R. glutinis, S. johnsonii and Acibenzolar-S-Methyl (ASM)). For this purpose were evaluated the area under the disease progress curve (AACPD), number of pods per plant (NVP), number of grains per pod (NGV), thousand grain mass (MMG) and productivity. For the results of the March cultivation, due to the low temperature, the maximum severity of bean common bacterial blight was 8% and the applications of yeasts were not significant for AACPD. The isolate R. glutinis showed the highest average of productivity with two applications, being 1006.44 kg ha-1. For October cultivation, R. glutinis and S. johnsonii isolates reduced AACPD by 66.84 and 58.42%, respectively with three applications. For productivity, R. glutinis and S. johnsonii showed no difference between the number of applications. The ASM showed a productivity of 4418.56 kg ha-1 with three applications. The results indicate that the yeasts R. glutinis and S. johnsonii reduce the severity of bean common bacterial blight and the most appropriate number of applications are two for both isolates.
Postharvest conservation methods such as heat shock can increase the nutritional profile of fruits, inducing greater accumulation of antioxidants that participate in the physiological maintenance of fruits. The objective of this work was to evaluate the antioxidant properties of “Sweet Grape” tomatoes treated with heat shock in pre-storage. “Sweet Grape” tomatoes were heat shocked in hot water (45°C) for 10 min. and stored at room temperature for 9 days. β-carotene, ascorbic acid, total phenolic compounds, and antioxidant activity (DPPH, ABTS, and FRAP) were evaluated every 3 days. The pulp and skin of the treated tomatoes had higher β-carotene content than the control during storage, according to the findings. The content of total phenolic compounds in the pulp reduced, regardless of the treatment. There was a reduction of ascorbic acid, but with significantly higher values in the fruits treated on the third and sixth days of storage. The DPPH antioxidant activity of the pulp decreased, regardless of the treatment. In the skin there was a significant effect of the treatment until the sixth day. There was no variation in the ABTS antioxidant activity of the pulp of the treated tomatoes. There was no significant effect of heat shock on the FRAP antioxidant activity of the pulp until the sixth day. Heat shock promoted an increase in β-carotene in tomato skin, which was related to increases in its DPPH antioxidant activity. The heat shock treatment promoted greater retention of ascorbic acid in the fruit, but it was not able to avoid its reduction during storage. The tomatoes’ antioxidant biochemical response to heat shock is most expressed in their skin.
Considerando a demanda por produtos fitossanitários alternativos aos tradicionais pesticidas, o objetivo deste trabalho foi avaliar a atividade antimicrobiana de formulados orgânico e químico a base de alecrim (Rosmarinus officinalis) sobre Xanthomonas campestris pv. campestris (Xcc) e Alternaria brassicae isolados de couve folha. A atividade antibacteriana in vitro foi realizada a partir de colônia jovens (com 32 h) de Xcc preparada em suspensão 1x10 8 UFC mL -1 com solução salina (0,85% de NaCl) estéril em tubos de ensaio contendo 5 mL do meio de cultura caldo nutriente, acrescido dos tratamentos 0 (meio de cultura); 0,5%; 1%; 2%; 4% e 6% (massa/volume), avaliando-se a absorbância a 580 nm. A atividade antifúngica in vitro foi feita em meio de cultura suco V8-ágar, esterilizado em autoclave e vertido em placas de Petri, avaliando-se diâmetro das colônias e esporulação, bem como a germinação de esporos em lâminas de microscopia recobertas com ágar-água 1%. Os formulados químico e orgânico reduziram o crescimento de Xcc em 74,5% e 54,8%, respectivamente. Houve inibição do crescimento micelial, esporulação e germinação de esporos de A. brassicae em todas as concentrações testadas de maneira dose-dependente. Houve inibição do crescimento micelial em 40% e 33%, esporulação em 61,35% e 54,5% e na germinação de conídios em 77,41% e 68,22% no formulado químico e orgânico, respectivamente, na
The study aimed to evaluate the control of Meloidogyne incognita in resistant and susceptible tomato genotypes treated with hydrogel containing avocado extracts (Persea americana Mill.). The methanolic extract of avocado seeds was evaporated and re-suspended in distilled water containing Tween 80 (0.6%). The extract was prepared with the following concentrations: 100, 200, 400, 800 and 1000 mg L ), for in vivo testing. The hydrogel containing avocado extract was added to the pits of tomato plants during transplanting, and after three days, M. incognita was inoculated. After 30 days, the relative chlorophyll content was assessed, along with the total volume of root, the number of galls and egg masses, viability of the egg mass, and number of eggs and juveniles per root system in 100 cm 3 of soil. From these assessments, the most effective dose in the control of nematodes was tested again with the extract concentrations of 1000, 2000, 4000, 6000 and 8000 mg L -1 in the hydrogel, which was added to the pits at the time of transplantation. After 30 days of inoculation the same evaluations were performed. In vitro, the concentration of 1000 mg L -1 of the avocado extract was the most effective in reducing the hatched juveniles, while motility and mortality were not influenced. In vivo, 1.0 g pit -1 dose in the first test had greater control of nematodes in susceptible plants for all variables assessed. It was incorporated into the pits of tomato plants for the realization of the second test. In this, the concentration of 8000 mg L -1 was the most effective in controlling M. incognita. Therefore, the avocado seed extract served in hydrogel has the potential to control M. incognita in tomato plants.
Wheat productivity is compromised by the number of diseases that affect it. The diseases control is basically effected by the use of fungicides, however, biological control has become important due especially to the demand for foods free of chemical compounds. The objective of this work was to evaluate the efficiency of yeasts in reducing diseases through the treatment of wheat seeds and the spraying of plants in the field. The tests were carried out in the field and laboratory, with the yeasts Candida albicans, Cryptococcus laurentii, Pichia guilliermondii, Rhodotorula glutinis, Zygoascus hellenicus and Saccharomyces cerevisiae compared with fungicide (carbendazim) and control with water. In the laboratory, seed health, germination, germination speed index, cold test and accelerated aging were analyzed. In the field, seed treatment and aerial application were carried out when the flag leaf was emitted and the occurrence of diseases, chlorophyll content, production components, productivity and production quality was evaluated. For the variables of production and quality of the wheat in field, the yeast Z. hellenicus was efficient for productivity resembling the fungicide. For the severity of diseases in field, parameters related to germination and seed health, yeasts were not efficient.
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