CRI-PhytRisk (www.cri-phytrisk.co.za) is a website that gives information on the risk of Citrus Black Spot (CBS) infection for each citrus growing region in South Africa on a daily basis, together with the suitability of fungicide spray conditions based on weather conditions as forecast by yr.no.

CRI-PhytRisk aims to answer the following questions: 1. Were weather conditions suitable for CBS infection? 2. When will fungicide application be most effective for CBS control, and should I alter my spray programme based on the CBS risk? 3. When will weather conditions be suitable for spraying (“Good2spray”)? 4. Can I keep records of the CBS risk of my region throughout the season in case of queries?

The website uses weather data input from yr.no to calculate the CBS risk and good-to-spray conditions for the current day (today), as well as a 6-day forecast. Historical weather and CBS forecast data are stored and available for browsing and download. Various CBS epidemiological models are integrated on the CRI-PhytRisk platform to allow improved decision support to citrus growers in CBS areas to improve fungicide spray timing, choice of fungicide (contact or systemic), as well as to indicate the CBS-risk experienced throughout the season.

  1. CBS risk a. Ascospore infection b. Pycnidiospore infection 2. Weather forecast 3. Good2spray daily forecast
  2. Breakdown of daily weather and Good2spray forecast in 3-hourly intervals

Who can use CRI-PhytRisk?

Anyone with internet access can view CRI-PhytRisk, including 12 days of weather, CBS and Good2spray forecasts: current day, 5 days previous as well as 6-day future forecast. Users with slow internet speed, or when using smart phones, can access a “Basic Site” to get faster browsing, without seeing interactive maps.

Users wanting to view or print historical data will have to be registered to use CRI-PhytRisk. Registered users can also set up email alerts for CBS risk in their region. – From the desk of Justin Chadwick, cga.co.za