Efeito de extrato vegetal de Schinus terebinthifolius no crescimento micelial de Colletotrichum acutatum do morangueiro

The Colletotrichum spp. is a significant strawberry pathogen causing yield losses of up to 50%. The most common method to control plant diseases is through the use of chemical fungicides. The findings of plants antimicrobial activities, low toxicity, and biodegradability of essential oils (EO), make them suitable for biological protection against fungal pathogens. The aim is to evaluate the inhibition of Colletotrichum acutatum by thyme, sage, and peppermint EO in vitro on detached strawberry leaves and determine EO chemical composition. Our results revealed that the dominant compound of thyme was thymol 41.35%, peppermint: menthone 44.56%, sage: α,β-thujone 34.45%, and camphor: 20.46%. Thyme EO inhibited C. acutatum completely above 200 μL L−1 concentration in vitro. Peppermint and sage EO reduced mycelial growth of C. acutatum. In addition, in vitro, results are promising for biological control. The detached strawberry leaves experiments showed that disease reduction 4 days after inoculation was 15.8% at 1000 μL L−1 of peppermint EO and 5.3% at 800 μL L−1 of thyme compared with control. Our findings could potentially help to manage C. acutatum; however, the detached strawberry leaves assay showed that EO efficacy was relatively low on tested concentrations and should be increased.

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Antifungal Activity of Propyl Disulfide from Neem (Azadirachta indica) in Vapor and Agar Diffusion Assays against Anthracnose Pathogens (Colletotrichum gloeosporioides and Colletotrichum acutatum) in Mango Fruit

Microorganisms ◽

10.3390/microorganisms9040839 ◽

2021 ◽

Vol 9 (4) ◽

pp. 839

Author(s):

Muhammad Rafiullah Khan ◽

Vanee Chonhenchob ◽

Chongxing Huang ◽

Panitee Suwanamornlert

Keyword(s):

Antifungal Activity ◽

Mycelial Growth ◽

Colletotrichum Gloeosporioides ◽

Colletotrichum Acutatum ◽

Model Parameters ◽

Pathogenicity Test ◽

Agar Diffusion ◽

Wide Range ◽

Significant Difference ◽

Diffusion Assay

Microorganisms causing anthracnose diseases have a medium to a high level of resistance to the existing fungicides. This study aimed to investigate neem plant extract (propyl disulfide, PD) as an alternative to the current fungicides against mango’s anthracnose. Microorganisms were isolated from decayed mango and identified as Colletotrichum gloeosporioides and Colletotrichum acutatum. Next, a pathogenicity test was conducted and after fulfilling Koch’s postulates, fungi were reisolated from these symptomatic fruits and we thus obtained pure cultures. Then, different concentrations of PD were used against these fungi in vapor and agar diffusion assays. Ethanol and distilled water were served as control treatments. PD significantly (p ≤ 0.05) inhibited more of the mycelial growth of these fungi than both controls. The antifungal activity of PD increased with increasing concentrations. The vapor diffusion assay was more effective in inhibiting the mycelial growth of these fungi than the agar diffusion assay. A good fit (R2, 0.950) of the experimental data in the Gompertz growth model and a significant difference in the model parameters, i.e., lag phase (λ), stationary phase (A) and mycelial growth rate, further showed the antifungal efficacy of PD. Therefore, PD could be the best antimicrobial compound against a wide range of microorganisms.

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Protective Antifungal Activity of Plantago major Extract Against the Phytopathogenic Fungi Phytophthora cinnamomi, Diplodia corticola and Colletotrichum Species

Proceedings ◽

10.3390/foods_2020-07678 ◽

2020 ◽

Vol 70 (1) ◽

pp. 94

Author(s):

Cláudia Ferreira ◽

Rui Oliveira

Keyword(s):

Antifungal Activity ◽

Secondary Metabolites ◽

Plant Extracts ◽

Phytophthora Cinnamomi ◽

Fungal Infections ◽

Petri Dish ◽

Phytopathogenic Fungi ◽

Colletotrichum Acutatum ◽

Lower Probability ◽

Plantago Major

Synthetic fungicides for crops protection raise environmental and human concerns due to accumulation in edible vegetables, showing significant toxicity to humans, and in soil, groundwater and rivers, affecting ecological balance. In addition, they are prone to the development of resistant strains because of the single target-based mechanism of action. Plant extracts provide attractive alternatives, as they constitute a rich source of biodegradable secondary metabolites, such as phenols, flavonoids and saponins, which have multiple modes of antifungal action and a lower probability of the development of resistant fungi. This work has the objective of identifying plant extracts with antifungal activity, aiming to contribute to food safety and sustainable agricultural practices. We selected a saponin-containing plant, Plantago major, and extracted secondary metabolites with 50% (v/v) ethanol, dried by evaporation, and dissolved in water. For antifungal activity, the phytopathogenic fungi Colletotrichum acutatum, Colletotrichum gloeosporioides, Colletotrichum godetiae, Colletotrichum nymphaeae, Diplodia corticola and Phytophthora cinnamomi were selected because they affect fruits and vegetables, such as strawberry, almond, apple, avocado, blueberry and chestnut trees. The aqueous extract was incorporated into PDA medium at different concentrations and mycelial discs were placed in the center of each Petri dish. Growth was measured as the radial mycelial growth at 3, 6, and 9 days incubation at 25 °C in the dark. The maximum growth inhibition (32.2%) was obtained against P. cinnamomi with 2000 µg/mL extract followed by C. gloeosporioides (25.7%) on the sixth day and by C. godetiae and C. nymphaeae (21.1%) on the ninth day. Results show that P. major presents antifungal activity in all phytopathogenic fungi tested and the extract can be used to protect important crops, by inhibiting the development of fungal infections and promoting food security and a sustainable agriculture.

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