Olive anthracnose is the most important fungal disease of the olive fruit worldwide, with the fungus Colletotrichum acutatum as the main cause of the disease in Greece. A total of 11 commercial biological plant protection products (bioPPPs) (Amylo-X^®, Botector^®, FytoSave^®, LBG 01F34^®, Mevalone^®, Polyversum^®, Remedier^®, Serenade^® ASO, Sonata^®, Trianum-P^®, Vacciplant^®), with various modes of action against the fungus C. acutatum, were evaluated by bioassays using detached fruits of two important olive Greek varieties, cv. Koroneiki and cv. Kalamon. Subsequently, the most effective bioPPPs were evaluated for their ability to induce plant defense mechanisms, by determining the expression levels of ten Olea europaea defense genes (Pal, CuaO, Aldh1, Bglu, Mpol, Lox, Phely, CHI-2, PR-10, PR-5). Remedier^®, Trianum-P^®, Serenade^® ASO, Sonata^®, and Mevalone^® were the most effective in reducing disease severity, and/or inhibiting the conidia production by the fungus at high rates. Post bioPPPs application, high expression levels of several olive plant defense genes were observed. This study provides insights into commercial bioPPPs’ effectiveness in controlling olive anthracnose, as well as biocontrol-agents-mediated modulation of olive defense mechanisms.

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.

Contamination of maize by aflatoxins produced mainly by Aspergillus flavus and fumonisins produced by Fusarium spp., including F . verticillioides , represents a major food and feed safety hazard that compromises grain quality and consumer and animal health. In this study, the biocontrol potential of different strains of epiphytic bacteria and yeasts was evaluated against aflatoxin and fumonisin production through both in vitro maize assays and a 3-year maize field trial under artificially inoculated or naturally infected conditions. Results demonstrated that all treatments with potential biological control agents reduced mycotoxin levels to varying degrees. Pantoea agglomerans strain B-379N consistently exhibited the highest efficacy, with applications under natural infection conditions reducing both aflatoxin and fumonisin levels. Other bacterial and yeast strains also showed notable inhibition rates; however, their performance was less consistent across trials, which may be attributed to variability in climatic conditions and differences in field adaptation. Overall, the findings of this study support the use of naturally occurring epiphytic bacteria and yeasts as an effective and sustainable preharvest strategy for mitigating multiple mycotoxins in maize.