Mutants of Botrytis cinerea with moderate and high resistance to pyraclostrobin, a Qo inhibitor of mitochondrial electron transport at the cytochrome bc 1 complex, were isolated at a high mutation frequency, after nitrosoguanidine mutagenesis and selection on medium containing pyraclostrobin and salicylhydroxamate (SHAM), a specific inhibitor of cyanide-resistant (alternative) respiration. Oxygen uptake in whole cells was strongly inhibited in the wild-type strain by pyraclostrobin and SHAM, but not in the mutant isolates. Cross-resistance studies with other Qo and Qi inhibitors (QoIs and QiIs) of cytochrome bc 1 complex of mitochondrial respiration showed that the mutation(s) for resistance to pyraclostrobin also reduced the sensitivity of mutant strains to other QoIs as azoxystrobin, fluoxastrobin, trifloxystrobin and picoxystrobin, but not to famoxadone and to the QiIs cyazofamid and antimycin-A. An increased sensitivity of pyraclostrobin-resistant strains to the carboxamide boscalid, an inhibitor of complex II, and to the anilinopyrimidine cyprodinil, a methionine biosynthesis inhibitor, was observed. Moreover, no effect of pyraclostrobin resistance mutation(s) on fungitoxicity of the hydroxyanilide fenhexamid, the phenylpyrrole fludioxonil, the benzimidazole benomyl, and to the phenylpyridinamine fluazinam, which affect other cellular pathways, was observed. Study of fitness parameters in the wild-type and pyraclostrobin-resistant mutants of B. cinerea showed that most mutants had a significant reduction in the sporulation, conidial germination and sclerotia production. Experiments on the stability of the pyraclostrobin-resistant phenotype showed a reduction of resistance, mainly in moderate resistant strains, when the mutants were grown on inhibitor-free medium. However, a rapid recovery of the resistance level was observed after the mutants were returned to a selective medium. Studies on the competitive ability of mutant isolates against the wild-type parent strain, by applications of a mixed conidial population, showed that, in vitro, all mutants were less competitive than the wild-type strain. However, the competitive ability of high resistant mutants was higher than the moderate ones. Pathogenicity tests on cucumber seedlings showed that all mutant strains tested exhibited an infection ability similar with the wild-type parent strain. Preventive applications of the commercial product of F-500 25EC (pyraclostrobin) were effective against lesion development on cotyledons by the wild-type, but ineffective, even at high concentrations, against disease caused by the pyraclostrobin-resistant isolates. Boscalid (F-510 50WG) was found equally effective against the disease caused by the wild-type or pyraclostrobin-resistant mutants. This is the first report indicating the appearance of B. cinerea strains resistant to QoI fungicides by the biochemical mechanism of site modification and the risk for field resistance.

Summary Seventy olive oil samples with protected geographical indication (PGI) or designation of origin (PDO) were analysed for fifty‐one target pesticides by means of gas chromatography coupled to mass spectrometry. The highest detection rates were observed for penconazole (n = 20), α‐endosulfan (n = 18), β‐endosulfan (n = 16) and flufenoxuron (n = 12). Four of the seventy investigated samples contained pesticide residues in levels exceeding MRLs. However, the investigated samples showed decreased occurrence and levels of pesticides residues in comparison with previous studies concerning samples from Greek conventional and organic cultivations. According to Spearman matrix, powerful correlations were obtained between α‐endosulfan and β‐endosulfan, detected as pair in thirteen samples and between flufenoxuron and penconazole detected as pair in eleven samples. Among Greek olive oil samples, the Cretan ones showed the lower detection rates and the lowest average number of detected pesticides per sample (1.75) in the case of pesticides positive samples.

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Eighty apple samples with protected geographical indication (PGI) or designation of origin (PDO) were analyzed for 51 target pesticides using the "quick, easy, cheap, effective, rugged and safe" (QuEChERS) method. Accuracy and precision were evaluated by means of recovery experiments at four concentration levels (10-250 µg/kg). Twelve pesticide residues were detected in 75 positive samples with an average number of detected pesticides per sample equal to 6.0. The highest detection rates were observed for chlorpyrifos (n=75), quinalphos (n=75) and parathion (n=73). Only 2 of the 80 investigated samples contained pesticide residues (parathionmethyl) in levels exceeding the maximum residue limits (MRLs). According to Spearman correlation analysis, the most powerful correlations were obtained between α-endosulfan and β-endosulfan (r=0.823) and between flufenoxuron and penconazole (r=0.683). Principal component analysis revealed similarities in the pesticides levels of all PDO/PGI samples, while the kind of product also significantly impacts its residue content.

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