Phytochemistry and antifungal potential of Datura inoxia Mill. on soil phytopathogen control

The application of chemical pesticides for the control of fungal diseases results in impacts on the environment and human health. The use of vegetal extracts with antifungal properties for the proper management of crops becomes a viable alternative, mainly for organic and family farming. The objective of this study was to carry out the phytochemical evaluation of Datura inoxia, evaluating its antifungal potential against the mycelial growth of Fusarium solani and Sclerotinia sclerotiorum. The extracts, aqueous and ethanolic, obtained from the leaves of the plant collected in areas of the municipality of Campo Grande, Mato Grosso do Sul, were submitted to phytochemical prospecting and quantification of flavonoids and total phenols. It was evaluated its antifungal activity at concentrations of 800, 1200, 1600, 2000, and 2400 μg 100 mL-1. Each concentration was separately incorporated into BDA agar, poured into Petri dishes, and inoculated with the mycelial disc of the fungus. The diameter of the colonies were measured daily. Two solutions were prepared as control, one containing the solvent added to PDA medium (ethanol solution), and another with only PDA medium (without D. inoxia extract, control). In both extracts were found the same diversity of secondary metabolites (nine classes). The ethanolic extract, a solvent of lower polarity than water, was more efficient in the extraction of these constituents. Alkaloids and phenolic compounds were the most frequent compounds (100%). In relation to antifungal activity, the ethanolic extract provided 100% inhibition of mycelial growth of Sclerotinia sclerotitorum in all concentrations, relative to the control. On the other hand, the growth of Fusarium solani was only negatively affected at the highest concentrations of 800 and 1200 μmL-1 100 mL-1. The antifungal potential of Datura inoxia was probably related to the abundance of alkaloids and phenolic compounds in its chemical constitution that negatively effects the development of the vegetative mycelium

Potencial de uso de plantas daninhas de áreas agrícolas e de pastagens do cerrado em Mato Grosso do Sul / Potential for use of weeds in agricultural areas and pastures of the cerrado in Mato Grosso do Sul

A busca por aumento da produtividade no sistema agropastoril do Cerrado Sul-Mato-Grossense tem motivado o aumento de uso de insumos químicos necessários no controle de pragas, contudo gerando preocupação quanto a contaminação ambiental. Métodos alternativos têm sido visados como recurso para diminuir os danos, manter a produção com qualidade, e promover a sustentabilidade ambiental. O objetivo deste trabalho foi investigar o potencial fitoquímico de espécies vegetais apontadas como invasoras em culturas e pastagens da biodiversidade brasileira com potencial no combate de doenças nas culturas. Assim, foi feita uma revisão de literatura. Os resultados apontam que as espécies invasoras em culturas e pastagem apresentam o uso popular medicinal e foram evidenciados metabólitos secundários que podem atuar como fontes de produtos bioativos

Líquido de castanha de caju: controle de patogênicos na cultura de soja: Cashew nut liquid: control of pathogens in soybean culture

Com o advento da tecnologia no campo muitas das dificuldades existentes na agricultura foram supridas ao longo dos anos, inúmeras pragas e doenças agrícolas deixaram de ser epidêmicas com o auxílio de produtos fitossanitários sintéticos e seu manejo integrado. Devido a isto, objetivou-se avaliar as atividades antifúngicas do líquido da castanha de caju (LCC) sobre o crescimento micelial de Fusarium solani e Sclerotinia sclerotiorum e em folhas destacadas in vitro sobre o crescimento micelial de S. sclerotiorum. O LCC obtido da empresa Resibras Company, São Paulo/SP foi submetido a análise física e química e as soluções hidroalcoólica nas concentrações de 800, 1200, 1600, 2000 e 2400 μg 100 mL-1, foram incorporadas, separadamente, em meio batata-dextrose-ágar (BDA), e vertidas em placas de Petri, seguido do disco de micélio do fungo, onde o diâmetro das colônias foi medido diariamente. Como controle utilizou-se apenas o ágar. O LCC foi submetido ao ensaio no combate ao mofo branco em folhas destacadas de soja inoculado com o fungo S. sclerotiorum. O trabalho se desenvolveu a partir da pulverização do LCC nas mesmas concentrações já citadas. Inoculado o fungo S. sclerotiorum foi avaliado o grau de severidade da doença em 24 e 72 horas. O LCC inibiu 29% do crescimento micelial de F. solani; nas concentrações 1600 μg 100 mL-1. Para S. sclerotiorum, a melhor concentração foi de 2000 μg 100 mL-1, com 100% de redução de crescimento. Atribui-se pouco potencial antifúngico do LCC contra o fungo em folhas destacadas de soja, com maiores de lesão

Pulverização foliar com agentes bacterianos de biocontrole para controle do crestamento bacteriano comum do feijoeiro

The objective of this work was to evaluate the effect of foliar spraying with bacterial biocontrol agents (BBAs) on the control of common bacterial blight (CBB) of bean, and on the induction of systemic resistance in bean plants. CBB control by BBAs was evaluated by spraying bean leaves 48 and 24 hours before and after pathogen inoculation (BPI and API, respectively), with: DFs93, Bacillus cereus; DFs513, Pseudomonas veronii; DFs769, B. cereus; the C01 combination, DFs93 + DFs769 + DFs831 (Pseudomonas fluorescens); the C03 combination, DFs348 (Bacillus sp.) + DFs769 + DFs831; and water (control). Systemic effects were analyzed after spraying DFs513, DFs769, C03, and water 72 and 48 hours BPI. Phaseolin production induced by DFs348, DFs513, DFs769, DFs831, and water was also assessed. DFs513, DFs769, and C03 significantly reduced disease incidence (area under disease progress curve), regardless of spraying time and disease severity when sprayed 72 and 48 hours BPI. The DFs769 and DFs831 isolates induced the accumulation of phytoalexin (phaseolin). Therefore, DFs513, DFs769, and C03 show potential for the biocontrol of CBB when applied preventively on bean leaves, besides inducing systemic resistance.O objetivo deste trabalho foi avaliar o efeito da pulverização foliar de agentes bacterianos de biocontrole (ABB) no controle do crestamento bacteriano comum do feijoeiro (CBC) e na indução de resistência sistêmica em plantas de feijão. O controle do CBC por ABB foi avaliado por meio da pulverização, em folhas de feijoeiro, 48 e 24 horas antes e depois da inoculação do patógeno (AIP e DIP, respectivamente), de: DFs93, Bacillus cereus; DFs513, Pseudomonas veronii; DFs769, B. cereus; combinação C01, DFs93 + DFs769 + DFs831 (Pseudomonas fluorescens); combinação C03, DFs348 (Bacillus sp.) + DFs769 + DFs831; e água destilada (testemunha). Os efeitos sistêmicos foram analisados após pulverização de DFs513, DFs769, C03 e água 48 e 72 horas AIP. Também foi avaliada a produção de faseolina induzida por DFs348, DFs513, DFs769, DFs831 e água. DFs513, DFs769 e C03 reduziram significativamente a incidência da doença (área abaixo da curva de progresso da doença), independentemente do momento da aplicação e da severidade da doença quando pulverizados 48 e 72 horas AIP. Os isolados DFs769 e DFs831 induziram o acúmulo de fitoalexina (faseolina). Portanto, DFs513, DFs769 e C03 apresentam potencial para o biocontrole do CBC quando pulverizados preventivamente em folhas de feijão, além de atuarem como indutores de resistência

Spectrum of biocontrol bacteria to control leaf, root and vascular diseases of dry bean

AbstractBacterial biocontrol agents, previously selected to control bacterial blight and anthracnose, were evaluated for the control of bacterial wilt, fusarium wilt, charcoal rot and angular leaf spot of dry beans. The seeds were microbiolized with these bacteria singly or in combinations. The microbiolization resulted in reduction of severity of all four diseases, showing wide spectrum of diseases control by these bacteria. However, the severity reduction of all four diseases by combination C01 composed of isolates DFs093 and DFs769 of Bacillus cereus and DFs831 of Pseudomonas fluorescens was significantly higher than if the seeds were microbiolized by a single isolate of a biocontrol agent

Biocontrol and seed transmission of Bipolaris oryzae and Gerlachia oryzae to rice seedlings

Bipolaris oryzae and Gerlachia oryzae, which cause rice brown spot and leaf scald, respectively, are mainly disseminated by seeds. The aim of this study was to evaluate the potential of seeds microbiolization to reduce transmission of these pathogens to seedlings by using the bacteria DFs185 (Pseudomonas synxantha), DFs223 (P. fluorescens), DFs306 (unidentified) and DFs418 (Bacillus sp.). Seeds naturally infested/infected with both pathogens were immersed in suspension of these bacteria (A540 = 0.5) individually or in saline solution (control treatment). After 30 minutes of agitation at 10 ºC, 400 seeds were submitted to a sanity test through the blotter method and the isolate DFs223 was the best to reduce the incidence of B. oryzae and G. oryzae in both seed lots evaluated. Seeds treated like above were sowed in sterilized vermiculite. Seed transmission and growth promotion were recorded after 21 days of incubation in the same conditions. The isolates DFs185 and DFs306 reduced transmission of both pathogens, although the isolate DFs306 was the one wich gave the greatest growth increases. The evaluation of the in vitro antibiosis showed that isolates inhibited the mycelial growth of both pathogens, except DFs306. It is possible to affirm that these bacteria have the potential to be used as a seed treatment for seed-borne disease control

Combination of biocontrol bacteria for rice seeds microbiolization: incidence and transmission of Bipolaris oryzae, and plant growth

Abstract: Several fungi species are associated with rice seeds, mainly Bipolaris oryzae, since it can kill seedlings and reduce production. Thus, the objective of this research was to study the potential of pre-selected combinations of rhizobacteria [DFs-C4 (DFs185/DFs416/DFs418) and DFs-C5 (DFs306/DFs416/DFs418)], when compared to their use individually (DFs185, DFs306, DFs416, DFs418), besides DFs223, evaluating the effect on the incidence and transmission of B. oryzae, incidence of phytopathogenic fungi and in the initial growth after rice seeds microbiolization. Seeds of cultivars BRS Pelota and BRS Querência (four lots each) were immersed in suspension of these bacteria or in saline solution (control) under agitation (for 30 minutes at 10 ºC). The fungi incidence was evaluated on blotter test. The pathogen transmission was assayed in sterilized vermiculite and humid chamber at 25 ± 2 ºC. After 15 days, the severity of the symptoms and the plant growth were evaluated. For both cultivars, the best treatments were DFs185 and DFs306, reducing the fungi incidence, including B. oryzae, as well as its transmission to seedlings, resulting in seedling length increase. The combination of biocontrol bacteria, individually efficient, did not result in a lower fungi incidence, or a reduction in the transmission of B. oryzae to the seedlings or an initial increase in seedling growth. Therefore, these rhizobacteria are more efficient when used individually