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
| Site |
Total
DMRisks |
Last 2 Weeks |
Detail |
Last Date of
Forecast |
DMRisks |
Duration (hr) |
* 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