Anthracnose is the main disease of olive fruit (Olea europaea L.) that is caused by different species of Colletotrichum spp. primarily belonging to two complexes, C. acutatum sensu lato (s.l.) and C. gloeosporioides s.l. (Cacciola et al. 2012; Damm et al. 2012; Schena et al. 2014). Observations in January 2015 in >20 olive groves in Aitoloakarnania region (West-Central Greece) showed severe symptoms of mummified olive fruits in about 50% of trees, in table olive cv. Kalamon. In March 2015, severe brown discoloration of inflorescences with 40-50% disease severity was observed in >15 orchards of cv. Koroneiki in the island of Zakynthos (West Greece). In autumn 2015, mature olive fruits showed typical anthracnose symptoms with dark necrotic lesions and rots with abundant orange conidial masses that resulted in premature fruit drop or mummification. Symptoms appeared also on tree twigs and leaves, leading to necroses, severe defoliation and branchlet death. The disease also affected the oil quality by increas...

Olive trees (Olea europaea L.) are among the most important fruit tree crops grown in Albania, covering an estimated 8% of the arable land of this country. The highest amount of olive production in...

Ochratoxin A (OTA) is a widely distributed mycotoxin and potent carcinogen produced by several fungal genera, but mainly by Aspergillus carbonarius. Grape contamination occurs in vineyards during the period between veraison and pre-harvest, and it is the main cause of OTA’s presence in wine. The aim of the current study was the evaluation of 6 chemical and 11 biological plant protection products (PPPs) and biocontrol agents in commercial vineyards of the two important Greek white wine varieties cv. Malagousia and cv. Savatiano. The PPPs were applied in a 4-year vineyard study as single treatments or/and in combinations as part of IPM systems. Subsequently, nine strains of Aspergillus carbonarius were investigated for their sensitivity against seven active compounds of synthetic fungicides. During the multi-year field trials, various novel management systems, including consortia of biocontrol agents, were revealed to be effective against Aspergillus sour rot and OTA production. However, expected variability was observed in the experimental results, indicating the dynamic character of biological systems and highlighting the possible inconsistency of PPPs’ efficacy in a changing environment. Furthermore, the IPM systems developed effectuated an optimized control of A. carbonarius, leading to 100% inhibition of OTA contamination, showing the importance of using both chemical and biological PPPs for disease management and prevention of fungal fungicide resistance. Finally, the majority of A. carbonarius tested strains were found to be sensitive against the pure active compounds used (fludioxonil, azoxystrobin, chlorothalonil, tebuconazole, cyprodinil, pyrimethanil and boscalid), with only a few exceptions of developed resistance towards boscalid.

Aspergillus carbonarius is considered one of the main fungi responsible for black and sour rot in grapes, as well as the production of the carcinogenic mycotoxin ochratoxin A. The global regulatory methyltransferase protein LaeA controls the production of various secondary metabolites in Aspergillus species, as well as influences sexual and asexual reproduction and morphology. The goal of this study was to investigate the role of the regulatory gene AclaeA in physiology, virulence, and ochratoxin A (OTA) production by deleting this gene from the genome of a wild-type A. carbonarius strain. The evaluation data on the morphological characteristics, virulence experiments in three different grape varieties, and OTA analysis of ΔAclaeA mutants showed that the growth and the OTA production by ΔAclaeA strains were significantly reduced. The mutant strains were also less virulent, producing 40–50% less conidia in three different cultivars of grape berries. Additionally, the gene AclaeA was considerably repressed after the application of three commercial biopesticides (Trianum-P^®, Vacciplant^®, and Serenade^® Max) and the essential oils (EOs) cinnamon, geranium, and thyme, which were also shown to inhibit OTA biosynthesis in A. carbonarius. The study of the regulatory gene AclaeA can contribute to a broader understanding of the role of secondary metabolites during A. carbonarius—grape interactions, as well as the discovery of the mode of action of biological plant protection products and EOs against this mycotoxigenic fungus.