Abstract:RESUMOPara verificar a eficiência de controladores biológicos e produtos qu ímic os p ara cont role da pod ridã o pa rda , foi conduzido um experimento a campo na safra de 2002 no município da Lapa-PR, com a cultivar BR-1. O objetivo do experimento foi fazer seleção de tratamentos com controle biológico comparando-os com químicos em sistemas de manejo utilizados na região. Como tratamentos foram utilizados quatro antagonistas previamente selecionados em trabalho de pós-colheita, isolados F1, F2, F4 (Trichothec… Show more
“…In Brazil, all commercial peach varieties are susceptible to brown rot and control is achieved through cultural practices, which reduce inoculum sources and create conditions less conducive for infection, associated with multiple fungicide applications (May De Mio et al 2004). The number of fungicide applications can vary depending on the region where peaches are produced; in some cases, nine or more sprays are performed within a season, starting at bloom, when susceptible flower parts are exposed, and ending near harvest on mature fruit (Moreira et al 2008;May De Mio et al 2011). The single-site fungicide groups: methyl benzimidazole carbamates (MBC), dicarboximides, quinone outside inhibitors (QoI), and demethylation inhibitor (DMI) fungicides are currently registered for controlling M. fructicola in peaches (AGROFIT 2017).…”
In this study, we investigated the sensitivity components of demethylation fungicide inhibitors (DMI-tebuconazole) for two different sensitivity genotypes of Monilinia fructicola (G461S mutants and wild-type isolates). These components included the fungicide resistance stability and fitness studied over the course of nine and five successive transfers in vitro and ex vivo, respectively, in the absence of fungicide. The results showed no effect of successive transfers on tebuconazole sensitivity of isolates with the G461S mutation for in vitro and ex vivo assays. Athough stable resistance was found, resistant isolates demonstrated a fitness disadvantage relative to the wild-type isolates. The in vitro assay revealed that wild-type isolates had higher germination rates and mycelial growth capacity; and when tested ex vivo, wild-type isolates could produce more spores and larger lesions in peach fruit. The competition studies corroborate the predicted fitness results, where resistant spores were less frequently re-isolated from two pairs of resistant and sensitive mixtures prepared at different ratios. The results obtained in this study have important implications for tebuconazole resistance management of stone-fruit orchards in Brazil and field tests are currently underway to confirm its practicality.
“…In Brazil, all commercial peach varieties are susceptible to brown rot and control is achieved through cultural practices, which reduce inoculum sources and create conditions less conducive for infection, associated with multiple fungicide applications (May De Mio et al 2004). The number of fungicide applications can vary depending on the region where peaches are produced; in some cases, nine or more sprays are performed within a season, starting at bloom, when susceptible flower parts are exposed, and ending near harvest on mature fruit (Moreira et al 2008;May De Mio et al 2011). The single-site fungicide groups: methyl benzimidazole carbamates (MBC), dicarboximides, quinone outside inhibitors (QoI), and demethylation inhibitor (DMI) fungicides are currently registered for controlling M. fructicola in peaches (AGROFIT 2017).…”
In this study, we investigated the sensitivity components of demethylation fungicide inhibitors (DMI-tebuconazole) for two different sensitivity genotypes of Monilinia fructicola (G461S mutants and wild-type isolates). These components included the fungicide resistance stability and fitness studied over the course of nine and five successive transfers in vitro and ex vivo, respectively, in the absence of fungicide. The results showed no effect of successive transfers on tebuconazole sensitivity of isolates with the G461S mutation for in vitro and ex vivo assays. Athough stable resistance was found, resistant isolates demonstrated a fitness disadvantage relative to the wild-type isolates. The in vitro assay revealed that wild-type isolates had higher germination rates and mycelial growth capacity; and when tested ex vivo, wild-type isolates could produce more spores and larger lesions in peach fruit. The competition studies corroborate the predicted fitness results, where resistant spores were less frequently re-isolated from two pairs of resistant and sensitive mixtures prepared at different ratios. The results obtained in this study have important implications for tebuconazole resistance management of stone-fruit orchards in Brazil and field tests are currently underway to confirm its practicality.
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