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Percorrer por autor "Oliveira, Eduardo Aguiar Barros"

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  • New alternative solutions against Colletotrichum fioriniae and elucidation of their mode of action
    Publication . Oliveira, Eduardo Aguiar Barros; Antón Domínguez, Begoña I.; Baptista, Paula; Patricia D.C., Schaker
    Olive cultivation is a cornerstone of the European agricultural sector, particularly in Portugal; however, it suffers substantial losses due to anthracnose, a disease caused by various Colletotrichum species that negatively impacts both the yield and quality of olive oil and table olives. Characterized by fruit lesions, defoliation, and necrosis, anthracnose is traditionally controlled through copper-based fungicides, which now face increasing restrictions due to their high environmental toxicity, necessitating the urgent development of sustainable alternatives. Among these, Volatile Organic Compounds (VOCs) have emerged as promising solutions as they are naturally produced via plant secondary metabolic pathways and exhibit significant activity against phytopathogens. The presente study evaluated the effect of six VOCs on mycelial growth, conidial production and germination of Colletotrichum fioriniae, and the half-maximal inhibitory concentration (IC50) was calculated based on mycelial growth data. The results demonstrated that 3,7-dimethyl-3-octanol and dihydromyrcenol were the most effective VOCs, achieving 100% mycelial growth inhibition at 10 µL, while their 1:1 mixture exhibited superior efficacy by reaching 78.28% inhibition at a total volume of 1.95 µL (IC50). Furthermore, these individual compounds directly inhibited conidial germination by 81.00% and 90.53%, respectively, whereas the mixture achieved complete (100%) inhibition. In detached fruit assays, although no compound prevented initial infection, all VOCs successfully reduced the disease progression, with the 1:1 mixture showing the highest efficacy by reducing disease severity by 21% and total fruit rot by 28%, compared with the positive control. Overall, these findings indicate that these volatiles limited fungal development and reduced disease impact, reinforcing their potential as sustainable alternatives to copper-based fungicides supporting further research on their physiological mechanisms of action and field-scale application strategies.
    2026Dissertação de mestrado Acesso aberto Ver mais