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Olive Anthracnose in Portugal Is Still Mostly Caused by Colletotrichum nymphaeae, but C. acutatum Is Spreading and C. alienum and C. cigarro Are Reported for the First Time

Publication . Cabral, Ana; Nascimento, Teresa; Azinheira, Helena; Loureiro, Andreia; Talhinhas, Pedro; Oliveira, Helena

Olive anthracnose, caused by Colletotrichum fungi, is responsible for major fruit yield losses and poor olive oil quality worldwide. In the Mediterranean basin, some Colletotrichum spp. appear to be replacing others, possibly due to climate change and modification in cultural systems. To update the situation in Portugal, 525 olive groves were surveyed throughout the country over two years, revealing a decrease in disease incidence, associated with scarcer rainfall and new cropping systems using less susceptible cultivars. A collection of 212 isolates was obtained, and phylogenetic analyses using a multi-locus sequencing approach (five and six loci in the acutatum and gloeosporioides species complex, respectively) revealed the presence of seven Colletotrichum species within the collection. Compared to surveys conducted in the first decade of the 21st century, the species composition of olive anthracnose pathogens in Portugal remains mostly unchanged, with C. nymphaeae as the prevalent species, followed by C. godetiae, but with C. acutatum geographically expanding and with C. alienum and C. cigarro being reported for the first time as causal agents of olive anthracnose in Portugal. A close attention to pathogen population shifts, in the context of climate change and modification of cultivation systems, is fundamental for anticipating plant protection measures.

2024-05Artigo científico

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How the “Olive Oil Polyphenols” Health Claim Depends on Anthracnose and Olive Fly on Fruits

Publication . Peres, Fátima; Gouveia, Cecília; Vitorino, Conceição; Oliveira, Helena; Ferreira-Dias, Suzana

Olive anthracnose, caused by Colletotrichum fungi, and the olive fruit fly Bactrocera olea are, respectively, the most important fungal disease and pest affecting olive fruits worldwide, leading to detrimental effects on the yield and quality of fruits and olive oil. This study focuses on the content of hydroxytyrosol (HYT) and its derivatives (the “olive oil polyphenols” health claim) in olive oils extracted from fruits of ‘Galega Vulgar’ and ‘Cobrançosa’ cultivars, naturally affected by olive anthracnose and olive fly. The olives, with different damage levels, were harvested from organic rainfed orchards, located in the center of Portugal, at four harvest times over three years. Galega oils extracted from olives with a higher anthracnose and olive fly incidence showed no conformity for the extra virgin olive oil (EVOO) and virgin olive oil (VOO) categories, presenting high acidity and negative sensory notes accompanied by the disappearance of oleacein. Conversely, no sensory defects were observed in Cobrançosa oils, regardless of disease and pest incidence levels, and quality criteria were still in accordance with the EVOO category. The total HYT and tyrosol (TYR) content (>5 mg/20 g) allows for the use of the “olive oil polyphenols” health claim on the label of all the analyzed Cobrançosa olive oils.

2024-06Artigo científico

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Olive oils from fruits infected with different anthracnose pathogens show sensory defects earlier than chemical degradation

Publication . Peres, Fátima; Talhinhas, Pedro; Afonso, Hugo; Alegre, Helena; Oliveira, Helena; Ferreira-Dias, Suzana

Anthracnose is the most important disease of olives responsible for olive oil depreciation. The aim of this study is to compare the negative effects of the most common olive anthracnose pathogens in Portugal, Colletotrichum nymphaeae, C. godetiae, or C. acutatum, on oil extracted from fruits of the most cultivated Portuguese olive cultivars, ‘Galega Vulgar’ and ‘Cobrançosa’. Healthy fruits (ripening index 3.5) were inoculated, incubated, and sampled over 14 days post-inoculation (d.p.i.) for symptom assessment and oil extraction. Virgin olive oil (VOO) was characterised by quality criteria parameters (acidity, peroxide value, UV absorbances, organoleptic assessment, fatty acid ethyl esters (FAEE)), total phenols (TPH), main fatty acids, and waxes compositions. Galega Vulgar fruits were more susceptible to anthracnose than Cobrançosa fruits. Colletotrichum nymphaeae was equally highly virulent for both cultivars, while C. godetiae was less virulent especially in Cobrançosa. VOO acidity increased reached 5% in Galega oils and 2% in Cobrançosa oils from fruits infected with C. nymphaeae or C. acutatum at 14 d.p.i. FAEE were higher than the legal limit for extra VOO in Galega oils from fruits at 7 d.p.i. with C. nymphaeae or C. acutatum, or 11 d.p.i. with C. godetiae. TPH decreased through the experiments with all the inoculated fungi. The musty sensory defect was detected in Galega and Cobrançosa VOO from fruits inoculated with C. nymphaeae or C. acutatum at 3 or 7 d.p.i. earlier than chemical degradation, respectively. The degradation levels of olive oils depended on the Colletotrichum species and olive cultivar

2021Artigo científico

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Olive Anthracnose in Portugal is still mostly caused by Colletotrichum nymphaeae, but C. acutatum is spreading and C. alienum and C. cigarro are reported for the first time