Cercospora Leafspot for 2024


Daily Infection Values:

Cercospora spores require leaf wetness to germinate and infect the leaves. Since the sensory technology for leaf wetness measurements are still being developed, the model utilizes relative humidity and air temperature measured within the sugar beet canopy to statistically correlate to disease occurrence. The current NDAWN Cercospora prediction model uses these relationships to determine favorable weather conditions for disease development as indicated by the DIV.

Daily Infection values (DIV) are determined from the total number of hours with relative humidity ≥ 85 percent in a 24 hour period (noon to noon) that were favorable for Cercospora development and the average air temperature during those hours. The noon to noon time period extends from noon yesterday to noon today and carries today's date. Daily infection values range from 0 (unfavorable) to 7 (very favorable). Generally the DIV increase with increasing number of hours of relative humidity ≥ 85 percent and with increasing temperature.

The NDAWN DIVs are presented in a graphical format and are based on the Two-Day Total Infection Value. If the Two-Day Total Infection Value ranges from 1 to 3, the infection risk is "Slight"; when the Two-Day Total ranges from 4 to 6, the infection risk is "Moderate", and when it ranges from 7 to 14, the infection risk is "Severe". A severe infection risk means conditions were extremely favorable for Cercospora development.

Daily Infection Values - Key
Slight Moderate Severe

DIVs are available on the NDAWN Homepage or the mobile-friendly NDAWN Crop Page. Regardless of which platform is utilized, users can select weather, growing degree day, sugarbeet root maggot and CLS data from the five NDAWN stations within the Minn-Dak growing area - Herman/Wheaton, Elbow Lake, Foxhome, Rothsay, Campbell, Wolverton, and Sabin in MN, and Wahpeton and Mooreton in ND. Each platform also features real-time weather conditions from each station for decision making and recordkeeping during spraying season. Specifically for CLS, the Daily Infection Values (DIVs) can be displayed in both table and graphical formats as well as providing a map with ’infection zones’ by station.

MDFC Cercospora Leafspot Program



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