BACKGROUND: Botryotinia fuckeliana (Botrytis cinerea) is a pathogen with a high risk of development of resistance to fungicides. Fungicide resistance was monitored during 2008-2011 in B. fuckeliana populations from both table-grape vineyards and greenhouse-grown strawberries in southern Italy. RESULTS:Isolates showing different levels of resistance to anilinopyrimidines (APs) were detected at high frequency (up to 98%) in fields treated intensively with APs (4-7 sprays season −1 ). A slight decrease in sensitivity to fludioxonil, always combined with AP resistance, was generally found at lower frequencies. The repeated use of fenhexamid on grapevine (3-8 sprays season −1 ) led to a strong selection of highly resistant isolates (up to 100%). Boscalid-resistant mutants were detected at very variable frequencies (0-73%). Occurrence of resistance to quinone outside inhibitors (QoIs) was also ascertained. Multiple fungicide resistance to 2-6 different modes of action were frequently recovered. Single nucleotide polymorphisms (SNPs) in the target genes Erg27, SdhB and cytb were associated with resistance to fenehexamid, boscalid and QoIs respectively. CONCLUSION: Resistance to the fungicides commonly used against grey mould on table grape and strawberry is quite common in southern Italy. This is an outcome of the incorrect use of fungicides, often because of the maximum number of detectable residues of plant protection products imposed by big international retailers, and underlines the crucial role of antiresistance strategies in integrated pest management.

Fungal diseases seriously affect agricultural production and the food industry. Crop protection is usually achieved by synthetic fungicides, therefore more sustainable and innovative technologies are increasingly required. the atmospheric pressure low-temperature plasma is a novel suitable measure. We report on the effect of plasma treatment on phytopathogenic fungi causing quantitative and qualitative losses of products both in the field and postharvest. We focus our attention on the in vitro direct inhibitory effect of non-contact Surface Dielectric Barrier Discharge on conidia germination of Botrytis cinerea, Monilinia fructicola, Aspergillus carbonarius and Alternaria alternata. A few minutes of treatment was required to completely inactivate the fungi on an artificial medium. Morphological analysis of spores by Scanning electron Microscopy suggests that the main mechanism is plasma etching due to Reactive oxygen Species or UV radiation. Spectroscopic analysis of plasma generated in humid air gives the hint that the rotational temperature of gas should not play a relevant role being very close to room temperature. In vivo experiments on artificially inoculated cherry fruits demonstrated that inactivation of fungal spores by the direct inhibitory effect of plasma extend their shelf life. Pretreatment of fruits before inoculation improve the resistance to infections maybe by activating defense responses in plant tissues.

Fluopyram-resistant mutants are currently rarely detected in the field sprayed with boscalid, but this may change with intensive exposure of the fungal population to fluopyram. PCR assays/methods developed in the study provide tools for fast monitoring of field populations and observing possible changes in population composition following fluopyram introduction, useful for the setting-up of appropriate preventive measures.

BACKGROUND: Cerevisane, made up of cell wall derivatives from the Saccharomyces cerevisiae strain LAS117, is proposed as a resistance inducer in plants. The mode of action of cerevisane was investigated through transcriptome analysis (RNA-Seq) carried out on leaves of potted vines cv. Italia grown in the greenhouse and sprayed at 1-week intervals with cerevisane. Analyses were performed at three time points after one and three sprays as well as on vines challenged with artificial inoculation with Plasmopara viticola, Erysiphe necator and Botrytis cinerea. RESULTS: Cerevisane proved effective against downy mildew and caused an increase in expression levels of several genes related to defense responses to fungal pathogens and other stresses and down-regulation of genes involved in several processesrelated to plant growth and development. Up-regulated genes included genes encoding (i) enzymes involved in hormone metabolism (i.e. salicylic acid, jasmonate, ethylene) and related plant responses, (ii) defense compounds (i.e. pathogenesis-related proteins, phenylalanine ammonia-lyase, stilbene synthases, lipoxygenase, leucine-rich repeat receptor-like protein kinases, non-specific plant lipid transfer proteins, serine-threonine protein kinases involved in signal transduction, superoxide dismutase and glutathione S-transferase involved in response to oxidative stress), (iii) secondary metabolites (i.e. phenylpropanoids, terpenoids, lignin), and (iv) photosynthetic processes (light harvesting chlorophyll A/B-binding proteins and components of the photosystems). CONCLUSION: Cerevisane can be a useful tool in protection schedules against downy mildew on grapevine aimed at reducing the usage of synthetic fungicides and preventing fungicide resistance. The results provide the first basic knowledge on the mode of action of yeast-derived elicitors effective against P. viticola on grapevine.

Spray schedules based on integration of BCAs or BOTs with fungicides are effective against grey mould and reduce the risk of fungicide resistance in B. cinerea and fungicide residues in grapes. © 2017 Society of Chemical Industry.