The Groundsman

October 2016

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Autumn dew points to disease risk As we move into autumn, moist air flows from the west create dewy mornings with wet leaf surfaces that are slow to dry. Combined with the milder conditions seen in recent years, it has led to serious early outbreaks of foliar diseases. With slowing grass growth and the high-risk conditions, problems with Microdochium Patch (Fusarium) outbreaks have already been reported. It is particularly serious with any damage affecting playing surface quality occurring now, lasting right through to the spring. A review of recent weather patterns highlights that seasonal autumn temperatures have typically risen up to two degrees over the past four decades. The trend is clearly now for warmer conditions continuing through the autumn and early winter. The changing weather patterns - including an increasing incidence of heavy rainfall - has significant implications for managing turf. GreenCast historic disease and weather records show that typically half of October days will see significant rain, with heavy dew on over 80 per cent of mornings, which creates increased risk of Microdochium Patch outbreaks during the month. Poa annua dominant swards and areas with lush growth that remain wet for extended periods, particularly with restricted air flow or deep thatch, will be especially susceptible. Disease stop Initial reports this season are that the Microdochium nivale pathogen is active, with outbreaks triggered by the onset of misty autumnal mornings in September an early warning of the potential risk this winter. During extended warm autumn growing conditions, Banner Maxx or Instrata will provide protection. As growing conditions slow, the contact+ Medallion TL will be more appropriate to reduce the pathogen presence in the thatch and protect the leaf through the cold. Results of new trials at STRI in Yorkshire have highlighted the value of proactive early treatments to reduce disease inoculum prior to periods of risk, to give long-lasting protection through weather conducive to disease. Continued growth Continued growing conditions through October could give the opportunity to further build carbohydrate reserves and strengthen turf ready for the winter. As daylight hours and light intensity falls, maintaining Primo Maxx programmes • Be aware of Microdochium Patch risk • Keep turf surfaces dry • Manage nutrition to avoid lush growth • Apply fungicides proactively October Top Tips to increase chloroplast numbers in the leaf could prove even more important to improve the efficiency of light utilisation.l World-leading on-line advice for turf • Up to the minute weather forecasting • Advance warning of turf diseases • Application zone for practical pointers • NEW interactive forums WEATHER UPDATE 55 the Groundsman October 2016 October UK average weather. October last year reinforced the trend to warmer growing conditions, although far drier than recent seasons. It was the precursor to an incredibly mild autumn and early winter, that continued right through to the end of the year Av Temp (°C) Sun (hours) Rain (mm) Days with more than 1mm of rain Diff to 30-yr av. Diff to 30-yr av. Diff to 30-yr av. Diff to 30-yr av. 2015 10.5 + 1.2 91 -2% 72 -44% 10 -4 2014 11.1 +1.8 83 -11% 159 +25% 18 +4 2013 11.2 +1.9 78 -12% 163 +28% 19 +5 2012 8.2 -1.1 91 -2% 126 -1% 16 +2 2011 11.3 +2.0 90 -3% 123 -3% 16 +2 2010 9.4 +0.1 106 +14% 101 -21% 13 -1 2009 10.4 +1.2 85 -9% 108 -15% 14 -2 30 year av. 9.3 °C 93 hrs. 127 mm 14 days Historic disease charts for last year showed that Microdochium Patch (Fusarium) risks really kicked-off during October, with several peaks through the month. Knowledge of weather triggering key risk periods helps with appropriate proactive preventative fungicide application timing

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