Evaluation of leaf spot sensitivity to fungicide chemistries and efficacy of disease control in peanut

Though they vary some in efficacy, a variety of fungicide products adequately control leaf spot and protect yields. Observations in 2017 and 2018 suggest the possibility of slight reductions in effectiveness of some fungicide chemistries, so growers should be diligent about rotating and/or mixing fungicide modes of action to prevent development of fungicide resistance. In addition, fungicide programs for control of leaf spot and other fungal pathogens of peanut need to be re-evaluated to maximize disease control efficacy and minimize the risk of fungicide resistance. Leaflets infected with late leaf spot were collected in 2018 and will be collected again in 2019 to determine fungicide sensitivity of fungal isolates. Fungicide programs will be evaluated again in 2019 to determine the efficacy of different fungicides across locations and years.