Trichoderma asperellum no controle de cancro do tronco em Carya illinoinensis

The objective of this work was to evaluate the ability of Trichoderma asperellum isolates and their culture filtrates to control Lasiodiplodia theobromae in vivo and to promote the growth of pecan seedlings. Two experiments were carried out, both in a greenhouse. In the first experiment, the aerial part of the plants was sprayed by biological control treatments and, 14 days later, the pathogen was inoculated into the stem, through injury. In the second experiment, the substrate was moistened with biological control treatments and 14 days later the pathogen was inoculated following the same methodology as the first experiment. The following parameters were evaluated: length of the aerial part, stem diameter, fresh mass of the aerial part and the root, dry mass of the aerial part and the root, incidence and severity of the disease. The comparison of means was performed using the Skott-Knott test at a 5% probability of error, using the SISVAR software. In both experiments, the greatest responses were obtained in the growth parameters evaluated in the treatments with the culture filtrates and with the spore suspension in relation to the treatment inoculated with the pathogen without the use of biological control treatments. These treatments also reduced the incidence and severity of stem canker in pecan seedlings, and the best treatment varied with the form of application. The isolates of T. asperellum and the culture filtrates stimulated the initial growth of the plants, decreasing the incidence and severity of stem canker in pecan plants, regardless of the form of application.O objetivo deste trabalho foi avaliar a ação de isolados de Trichoderma asperellum e de seus filtrados de cultura no controle de Lasiodiplodia theobromae in vivo e na promoção do crescimento de mudas de nogueira-pecã. Foram desenvolvidos dois experimentos, ambos em casa de vegetação. No primeiro experimento, a parte aérea das plantas foi aspergida pelos tratamentos de controle biológico e 14 dias após foi inoculado o patógeno no caule, por meio de ferimento. No segundo experimento, o substrato foi umedecido com os tratamentos de controle biológico e 14 dias após foi feita a inoculação do patógeno seguindo mesma metodologia do primeiro experimento. Foram avaliados os seguintes parâmetros: comprimento da parte aérea, diâmetro do caule, massa fresca da parte aérea e da raiz, massa seca da parte aérea e da raiz, incidência e severidade da doença. A comparação das médias foi realizada pelo teste de Skott-Knott a 5% de probabilidade de erro, com o software SISVAR. Nos dois experimentos, obtiveram-se as maiores respostas nos parâmetros de crescimento avaliados nos tratamentos com os filtrados de cultura e com a suspensão de esporos, em relação ao tratamento inoculado com o patógeno sem o uso dos tratamentos de controle biológico. Esses tratamentos também reduziram a incidência e a severidade do cancro do tronco em mudas de nogueira-pecã, sendo que o melhor tratamento variou com a forma de aplicação. Os isolados de T. asperellum e os filtrados de cultura estimularam o crescimento inicial das plantas, diminuíram a incidência e a severidade do cancro do tronco nas plantas de nogueira-pecã, independente da forma de aplicação

Response of soybean and corn to soil mechanical intervention and agricultural gypsum application to the soil surface

 O gesso agrícola tem sido apontado como importante ferramenta para a melhoria do perfil químico do solo, porém, as respostas das culturas, especificamente as de grãos são contraditórias. Para as intervenções mecânicas de solo, os resultados existentes revelam efeito físico pouco duradouro e com pouco impacto sobre o rendimento de grãos. Por isso, o objetivo do trabalho foi verificar as respostas do milho e da soja a intervenções mecânicas do solo e aplicação de gesso agrícola em superfície. O experimento consistiu no cultivo de duas safras de grãos de soja (2009/2010 e 2011/2012) e duas de milho (2010/2011 e 2012/2013), com aplicação de gesso agrícola (0; 2; 4 e 6 Mg ha-1) em superfície no período invernal de 2009, após 12 anos de plantio direto contínuo e após dois tipos de intervenções mecânicas: (escarificação e aração+gradagem). Os resultados mostraram que a soja responde a intervenções mecânicas realizadas em área de plantio direto contínuo e, o incremento no rendimento de grãos com o uso de gesso agrícola foi de apenas 10% (114 kg ha-1) e somente na safra 2011/2012. Na cultura do milho houve maior incremento no rendimento de grãos com as doses de gesso em relação à soja e com variação na resposta ao gesso na safra 2010/2011 com as intervenções mecânicas aplicadas no plantio direto contínuo.Agricultural gypsum is considered an important tool in the improvement of soil chemical properties; however, crop responses to its application are contradictory. Studies have shown that the physical effects of soil mechanical intervention is short-lasting and has little impact on grain yield. Therefore, the aim of this study was to investigate corn and soybean response to soil mechanical interventions and to the application of agricultural gypsum to soil surface. The experiment involved cultivation of two crops each of soybean (i. e., 2009/2010 and 2011/2012 crop years) and corn (i. e., 2010/2011 and 2012/2013 crop years) with application of agricultural gypsum (0, 2, 4 and 6 Mg ha-1) to the soil surface during the winter of 2009, after 12 years under continuous no-tillage system and two types of mechanical intervention: chisel plowing and plowing+harrowing. Soybean responded to mechanical interventions conducted in an area under continuous no-tillage system, but showed an increase of only 10% (114 kg ha-1) in the grain yield with the use of agricultural gypsum in the 2011/2012 crop year. Gypsum caused a higher increase in the grain yield of corn than that of soybean. Moreover, the crop response to gypsum application varied considerably in the 2010/2011 crop year after mechanical interventions under continuous no-tillage cultivation

Submerged cultivation of Nigrospora sp. in batch and fed-batch modes for microbial oil production

Microbial lipids are a valuable source of potential biofuels and essential polyunsaturated fatty acids. The optimization of the fermentation conditions is a strategy that affects the total lipid concentration. The genus Nigrospora sp. has been the target of investigations based on its potential bioherbicidal action. Therefore, this study developed a strategy to maximize the biomass concentration and lipid accumulation by Nigrospora sp. in submerged fermentation. Different media compositions and process variables were investigated in shaken flasks and bioreactor in batch and fed-batch modes. Maximum biomass concentration and lipid accumulations were 40.17 g/L and 21.32 wt% in the bioreactor, which was 2.1 and 5.4 times higher than the same condition in shaken flasks, respectively. This study presents relevant information to the production of fungal lipids since few investigations are exploring the fed-batch strategy to increase the yield of fungi lipids, as well as few studies investigating Nigrospora sp. to produce lipids

Development of a Solid Bioherbicide Formulation by Spray Drying Technology

This study aimed to compare the herbicidal activity of solid formulas obtained by spray drying with conventional liquid formulas containing biomolecules produced by submerged cultivation of the fungus Diaporthe sp. in a stirred-tank bioreactor. The solid formula presented the highest phytotoxicity on plant control (96.7%) and the phytotoxicity was directly related to the concentration of fermented broth in the formula. The use of adjuvant improved the efficiency of the bioherbicide. Dry matters of treatments were lower than the control and this was correlated with an increase in oxidative stress, since the activity of the antioxidant enzymes such as superoxide dismutase and guaiacol peroxidase increased in the treatment with a high level of phytotoxicity. Spray drying technology is a promising tool to concentrate bioherbicide without the loss of bioactive compounds since one of the major challenges in the production of bioherbicides is the low concentration of active ingredients in the fermented broth

Spray-Dried Powder Containing Chitinase and β-1,3-Glucanase with Insecticidal Activity against Ceratitis capitata (Diptera: Tephritidae)

This study focused on obtaining a spray-dried powder containing chitinase and β-1,3-glucanase as active ingredients for the control of agricultural pests. Different carriers were tested in the spray drying of these enzymes. The effectiveness of the application of the enzymes was evaluated against Ceratitis capitata (Diptera: Tephritidae). The combination of maltodextrin (2.5% w/v), gum Arabic (2.5% w/v), and soluble starch (5.0% w/v) as carriers showed the best result of residual activity of β-1,3-glucanase (88.36%) and chitinase (69.82%), with a powder recovery of 45.49%. The optimum conditions for the operational parameters of the spray drying process were: inlet air temperature of 120 °C, drying airflow rate of 1.1 m3/min, feed flow rate of 5.8 mL/min, and nozzle air pressure of 0.4 MPa. The powder produced showed 65.6% efficiency for the control of the fly. These results demonstrated the possibility of using the spray drying process to obtain an enzymatic potential product for biological pest control