Earthworms and Fusarium oxysporum: effect on strawberry plant growth and production / Minhocas e Fusarium oxysporum: efeito no crescimento e produção do morangueiro

Earthworms are soil invertebrates that play an important environmental role and are often referred to as “ecosystem engineers”. These invertebrates can influence several organisms, from microscopic life forms to plants. Although many works had reported positive effects of earthworms on plant growth, studies combining these invertebrates and soil pathogens showed numerous positive interactions. Fusarium wilt is a global disease that can cause severe damage to strawberry fields. The aim of this study was to evaluate the effects of inoculation of earthworms (Lumbricus terrestris) and Fusarium wilt (Fusarium oxysporum f. sp. fragariae) in strawberry plants. This greenhouse experiment was carried out in the University of Seville School of Agricultural Engineering, Utrera City, Spain. Strawberries (Rooted cuttings) were planted in plastic pots and administered the following treatments: Control (absence of F. oxysporum f. sp. fragariae and earthworms), T1 (absence of F. oxysporum f. sp. fragariae, two L. terrestris per pot), T2 (inoculum of F. oxysporum f. sp. fragariae, absence of L. terrestris), and T3 (inoculum of F. oxysporum f. sp. fragariae and two L. terrestris). Weekly fruit production was measured for seven months. After this period the shoot fresh weight and the leaf nutrient content was measured. The results obtained showed no interaction between L. terrestris and F. oxysporum f. sp. fragariae on strawberry production. T1 treatment resulted in fruit production superior to other treatments, including the control. An absence of differences in dry shoot matter was observed with earthworm treatment, and small differences were found in the leaf nutrient content. The earthworm inoculation was unable to suppress the negative effects of Fusarium wilt in strawberry production. However, positive effects such as a reduction in the disease severity were found in the earthworm treated plants...(AU)

Minhocas são invertebrados do solo que participam de importantes funções ambientais e são consideradas “engenheiros do ecossistema”. Estes animais podem influenciar diversos organismos, desde formas microscópicas até mesmo plantas. Embora muitos trabalhos citem efeitos positivos da atividade de minhocas no crescimento das plantas, estudos combinando estes invertebrados e patógenos de solo têm demonstrado inúmeras interações. A murcha-de-fusarium é uma doença mundialmente difundida capaz de causar grandes danos ao morangueiro, e seu controle geralmente é ineficiente. O objetivo deste estudo foi avaliar os efeitos da inoculação de minhocas (Lumbricus terrestris) e murcha de fusarium (Fusarium oxysporum f. sp. fragariae) em plantas de morango. O experimento foi conduzido em ambiente protegido na Escola de Engenharia Agrícola da Universidade de Sevilha, Utrera - Espanha. Plantas de morango (estacas enraizadas) foram plantadas em vasos plásticos e submetidas aos seguintes tratamentos: Controle (ausência de F. oxysporum f. sp. fragariae e minhocas), T1 (ausência de F. oxysporum f. sp. fragariae, duas L. terrestris por vaso), T2 (inóculo de F. oxysporum f. sp. fragariae, ausência de L. terrestris) e T3 (inóculo de F. oxysporum f. sp. fragariae e duas L. terrestris). A produção de frutos foi semanalmente mensurada durante sete meses. Após este período, foram avaliadas a matéria seca da parte aérea e o conteúdo de nutrientes das folhas. Os resultados obtidos não demonstraram entre L. terrestris e F. oxysporum f. sp. fragarie na produção de frutos. Mas, o tratamento T1 apresentou produção superior a todos os outros tratamentos, incluindo o controle. Foram observadas pequenas diferenças no conteúdo de nutrientes das folhas e não se verificou efeito das minhocas na massa seca da parte aérea. A inoculação de minhocas não foi capaz de reduzir os efeitos negativos da murcha de fusarium na produção do morangueiro...(AU)

Effect of fungicide on Fusarium verticillioides mycelial morphology and fumonisin B1 production

The effect of fludioxonil + metalaxyl-M on the mycelial morphology, sporulation and fumonisin B1 production by Fusarium verticillioides 103 F was evaluated. Scanning electron microscopy analysis showed that the fungicide caused inhibition of hyphal growth and defects on hyphae morphology such as cell wall disruption, withered hyphae, and excessive septation. In addition, extracellular material around the hyphae was rarely observed in the presence of fludioxonil + metalaxyl-M. While promoting the reduction of mycelial growth, the fungicide increased sporulation of F. verticillioides compared to the control, and the highest production occurred on the 14th day in the treatments and on the 10th day in the control cultures. Fumonisin B1 production in the culture media containing the fungicide (treatment) was detected from the 7th day incubation, whereas in cultures without fungicide (control) it was detected on the 10th day. The highest fumonisin B1 production occurred on the 14th day, both for the control and for the treatment. Fludioxonil + metalaxyl - M can interfere in F. verticillioides mycelial morphology and sporulation and increase fumonisin B1 levels. These data indicate the importance of understanding the effects of fungicide to minimize the occurrence of toxigenic fungi and fumonisins.(AU)

Efficacy of fungal decolorization of a mixture of dyes belonging to different classes

Dyes are the most difficult constituents to remove by conventional biological wastewater treatment. Colored wastewater is mainly eliminated by physical and chemical procedures, which are very expensive and have drawbacks. Therefore, the advantage of using biological processes, such as the biotransformation of dyes, is that they may lead to complete mineralization or formation of less toxic products. To prove the possibility of using fungal processes for decolorization and other applications, the analysis of the toxicity of the processes' products is required. The decolorization of the mixture of two dyes from different classes - triphenylmethane brilliant green and azo Evans blue (GB - total concentration 0.08 g/L, proportion 1:1 w/w) - by Pleurotus ostreatus (BWPH and MB), Gloeophyllum odoratum (DCa), RWP17 (Polyporus picipes) and Fusarium oxysporum (G1) was studied. Zootoxicity (Daphnia magna) and phytotoxicity (Lemna minor) changes were estimated at the end of the experiment. The mixture of dyes was significantly removed by all the strains that were tested with 96 h of experimental time. However, differences among strains from the same species (P. ostreatus) were noted. Shaking improved the efficacy and rate of the dye removal. In static samples, the removal of the mixture reached more than 51.9% and in shaken samples, more than 79.2%. Tests using the dead biomass of the fungi only adsorbed up to 37% of the dye mixture (strain BWPH), which suggests that the process with the living biomass involves the biotransformation of the dyes. The best results were reached for the MB strain, which removed 90% of the tested mixture under shaking conditions. Regardless of the efficacy of the dye removal, toxicity decreased from class V to class III in tests with D. magna. Tests with L. minor control samples were classified as class IV, and samples with certain strains were non-toxic. The highest phytotoxicity decrease was noted in shaken samples where the elimination of dye mixture was the best.(AU)

Impact of water potential on growth and germination of Fusarium solani soilborne pathogen of peanut

Studies were conducted to determine the effect of osmotic and matric stress on germination and growth of two Fusarium solani strains, the etiological agent responsible of peanut brown root rot. Both strains had similar osmotic and matric potential ranges that allowed growth, being the latter one narrower. F. solani showed the ability to grow down to -14 MPa at 25 °C in non-ionic modified osmotic medium, while under matric stress this was limited to -8.4 MPa at 25 °C. However, both strains were seen to respond differently to decreasing osmotic and matric potentials, during early stages of germination. One strain (RC 338) showed to be more sensitive to matric than osmotic (non ionic) and the other one (RC 386) showed to be more sensitive to osmotic than matric imposed water stress. After 24 h of incubation, both isolates behaved similarly. The minimum water potential for germination was -8.4 MPa on glycerol amended media and -5.6 MPa for NaCl and PEG amended media, respectively. The knowledge of the water potential range which allow mycelia growth and spore germination of F. solani provides an inside to the likely behaviour of this devastating soilborne plant pathogen in nature and has important practical implications.

Earthworms and Fusarium oxysporum: effect on strawberry plant growth and production / Minhocas e Fusarium oxysporum: efeito no crescimento e produção do morangueiro

Earthworms are soil invertebrates that play an important environmental role and are often referred to as “ecosystem engineers”. These invertebrates can influence several organisms, from microscopic life forms to plants. Although many works had reported positive effects of earthworms on plant growth, studies combining these invertebrates and soil pathogens showed numerous positive interactions. Fusarium wilt is a global disease that can cause severe damage to strawberry fields. The aim of this study was to evaluate the effects of inoculation of earthworms (Lumbricus terrestris) and Fusarium wilt (Fusarium oxysporum f. sp. fragariae) in strawberry plants. This greenhouse experiment was carried out in the University of Seville School of Agricultural Engineering, Utrera City, Spain. Strawberries (Rooted cuttings) were planted in plastic pots and administered the following treatments: Control (absence of F. oxysporum f. sp. fragariae and earthworms), T1 (absence of F. oxysporum f. sp. fragariae, two L. terrestris per pot), T2 (inoculum of F. oxysporum f. sp. fragariae, absence of L. terrestris), and T3 (inoculum of F. oxysporum f. sp. fragariae and two L. terrestris). Weekly fruit production was measured for seven months. After this period the shoot fresh weight and the leaf nutrient content was measured. The results obtained showed no interaction between L. terrestris and F. oxysporum f. sp. fragariae on strawberry production. T1 treatment resulted in fruit production superior to other treatments, including the control. An absence of differences in dry shoot matter was observed with earthworm treatment, and small differences were found in the leaf nutrient content. The earthworm inoculation was unable to suppress the negative effects of Fusarium wilt in strawberry production. However, positive effects such as a reduction in the disease severity were found in the earthworm treated plants...

Minhocas são invertebrados do solo que participam de importantes funções ambientais e são consideradas “engenheiros do ecossistema”. Estes animais podem influenciar diversos organismos, desde formas microscópicas até mesmo plantas. Embora muitos trabalhos citem efeitos positivos da atividade de minhocas no crescimento das plantas, estudos combinando estes invertebrados e patógenos de solo têm demonstrado inúmeras interações. A murcha-de-fusarium é uma doença mundialmente difundida capaz de causar grandes danos ao morangueiro, e seu controle geralmente é ineficiente. O objetivo deste estudo foi avaliar os efeitos da inoculação de minhocas (Lumbricus terrestris) e murcha de fusarium (Fusarium oxysporum f. sp. fragariae) em plantas de morango. O experimento foi conduzido em ambiente protegido na Escola de Engenharia Agrícola da Universidade de Sevilha, Utrera - Espanha. Plantas de morango (estacas enraizadas) foram plantadas em vasos plásticos e submetidas aos seguintes tratamentos: Controle (ausência de F. oxysporum f. sp. fragariae e minhocas), T1 (ausência de F. oxysporum f. sp. fragariae, duas L. terrestris por vaso), T2 (inóculo de F. oxysporum f. sp. fragariae, ausência de L. terrestris) e T3 (inóculo de F. oxysporum f. sp. fragariae e duas L. terrestris). A produção de frutos foi semanalmente mensurada durante sete meses. Após este período, foram avaliadas a matéria seca da parte aérea e o conteúdo de nutrientes das folhas. Os resultados obtidos não demonstraram entre L. terrestris e F. oxysporum f. sp. fragarie na produção de frutos. Mas, o tratamento T1 apresentou produção superior a todos os outros tratamentos, incluindo o controle. Foram observadas pequenas diferenças no conteúdo de nutrientes das folhas e não se verificou efeito das minhocas na massa seca da parte aérea. A inoculação de minhocas não foi capaz de reduzir os efeitos negativos da murcha de fusarium na produção do morangueiro...