Effect of Fraze Mowing on Spring Dead Spot caused by Ophiosphaerella herpotricha of Bermudagrass

Spring dead spot, caused by Ophiosphaerella spp., is the most serious disease limiting bermudagrass use in the transition zone. Current management practices require an integrated approach that may take multiple years to achieve satisfactory control. Recently, an intensive cultivation practice termed fraze mowing has gained popularity for sports turf use in the United States. A split plot field experiment was conducted to assess the impact of fraze mowing alone, and in combination with other control practices, on spring dead spot. On 30 June 2015, plots were fraze mowed (main plot) at the 4 mm or 8 mm depth, or not cultivated. Nitrogen was applied weekly at 24.4 kg N ha^-1 as either calcium nitrate or ammonium sulfate for six weeks after fraze mowing. Manganese was applied as 98 kg manganese sulfate ha^-1 every other week with fertilizer, or left untreated. Plots were also either treated with penthiopyrad (0.107 g a.i. m^-2) twice on 30 June and 14 October 2015, or left untreated. Neither nitrogen source nor manganese application had a significant effect on spring dead spot severity. Plots fraze mowed at 8 mm had lower spring dead spot severity than non-fraze mowed plots. Fungicide treated plots had less spring dead spot than non-fungicide treated plots, but no difference was detected between non-fraze mowed plots treated with fungicide and non-fungicide treated plots fraze mowed at 8 mm.