DMCast - Grape Downy Mildew Forecast
  • The downy mildew pathogen has complicated interactions with weather conditions. DMCast uses hourly weather data (relative humidity, temperature, and leaf wetness) to determine when infections are likely to occur.
  • DMCast reliably predicts the date of first infection in the vast majority of seasons. It also is quite good at forecasting the risk of foliar and fruit infection during the growing season. Although berries develop resistance to further infections around 2 to 3 weeks postbloom, other parts of the grapevine, including the rachis, continue to be susceptible. And foliar infection can continue to occur so long as new leaves are being produced.
  • In mid-summer, disease may not develop after DMCast-predicted infection periods, because the preceding weather was hot and dry enough to inactivate downy mildew sporangia ahead of the conducive weather event. In this way, DMCast may over-predict infection risk.
  • Even after hot and dry weather has inactivated sporangia, if weather conditions become consistently favorable again and the fungus becomes re-established, DMCast will again provide reliable infection risk forecasts for foliar disease. At such times, always use DMCast in conjunction with vineyard monitoring for actively sporulating downy mildew infections.

    • STEP 1: Summary - Choose Year

    Summary for Year:
    Site Total
    DMRisks    		 Last 2 Weeks Detail
    Last Date of
    Forecast    		 DMRisks Duration (hr)
    Albion 34 08/27 1 4
    Appleton, North 24 08/27 2 3
    Appleton, South 40 08/18 9 58
    Arkport N/A* 08/27 - -
    Barrington N/A 08/27 - -
    Batavia 30 08/27 8 85
    Branchport 17 08/26 1 2
    Chazy 0 08/27 0 -
    Clifton Park 50 08/27 8 56
    Clintondale 30 08/27 3 15
    Dresden N/A 08/25 - -
    Eden 75 08/27 10 71
    Elba 60 08/27 10 67
    Farmington 44 08/19 4 12
    Fredonia 29 08/27 2 10
    Freeville 85 08/25 11 75
    Friend N/A 08/27 - -
    Gainesville N/A 08/27 - -
    Geneva 54 08/27 9 44
    Groveland N/A 08/27 - -
    Guilderland 0 08/27 0 -
    Himrod N/A 08/27 - -
    Hudson 65 08/27 11 37
    Ithaca N/A 06/19 - -
    Knowlesville 70 08/27 10 62
    Lansing N/A 08/26 - -
    Lockport 16 08/07 5 20
    Lyndonville 6 08/27 0 -
    Marlboro 37 08/27 7 20
    Mexico N/A 08/27 - -
    Naples N/A 08/15 - -
    Pavilion N/A 08/27 - -
    Potter 53 08/27 5 17
    Prattsburg N/A 08/27 - -
    Pulteney 39 08/27 3 12
    Red Hook 83 08/27 15 111
    Savannah N/A 08/22 - -
    Scriba 20 07/15 4 18
    Sodus 46 08/27 4 18
    Valois 27 08/27 3 7
    Waterport 57 08/27 9 92
    Watkins Glen 20 08/27 1 8
    Wayland N/A 08/27 - -
    Williamson, Motts 37 08/27 3 10
    * N/A indicates that DMCast could not be executed properly because of the lack of required weather elements (air temperature, relative humidity, precipitation, and leaf wetness) for the model. Press 'Step 2' button to continue with DMCast forecasting for your location and grape cultivar.
    If you want EXPERT features, try http://www.nysaes.cornell.edu/pp/faculty/seem/dmcast/index.php?expert=1