Brazilian isolates of Monilinia fructicola from peach do not present reduced sensitivity to iprodione
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The dicarboximide fungicide iprodione has been used in Brazilian peach orchards for more than three decades to control brown rot and there are no studies on sensitivity to Monilinia fructicola in the country. In addition, isolates with reduced sensitivity to other important groups of fungicides have already been reported in Brazilian isolates. The sensitivity of M. fructicola to iprodione was evaluated using discriminatory doses and concentration resulting in 50% inhibition of mycelial growth (EC50) values. In total, 174 isolates collected from the main peach production areas were characterized for fungicide sensitivity. Disease control efficacy (DCE) was determined by comparing lesion inhibition on iprodione treated fruits with those without fungicide treatment. No resistant phenotypes were found in the M. fructicola population and 71.8% of the isolates were extremely sensitive to iprodione. The EC50 values of the isolates ranged from 0.13 to 1.01 μg/mL. DCE in wounded and non-wounded fruit was greater than 85% providing an efficient control in controlled conditions. These results suggest that iprodione could be integrated into disease management programs to prevent the establishment of resistant populations as already reported to other fungicides.
KeywordsBrown rot of peach Dicarboximides Fungicide resistance Chemical control
This study was financed in part by the Cordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil (CAPES) - Finance Code 001. The last author received research fellowships from Conselho Nacional de Desenvolvimento Científico e Tecnológico - Brazil (CNPQ).
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