Background Information

This website and the risk advisory service contained within are offered free of charge to the public. The advisory was developed to provide wheat and barley growers with information to help them make more informed decisions about disease management. It is not intended that the advisory be used solely to schedule fungicide treatment, rather it is intended to aid growers and crop managers in that decision process. Understanding the relationship of weather/enviroment to scab development is one of the keys to implementing sound management strategies. The advisory is only a tool to illustrate the relative risk for scab development. The models used to develop the risk advisory are experimental. Any management decisions made based on the information contained herein are strictly the responsibility of the person or persons making such decisions. No warranty or guarantee is expressed or implied.

Risk Assesments:

Risk of scab infection is based on a combination of factors: a) temperature and precipitation for the past 7 days; b) forecasted weather for the next 48-72 hours; and c) estimated crop condition (stage) in each area.

Favorable temperatures: 55 to 90F
Favorable moisture: frequent or prolonged rainfall, rel. humidity above 90% and/or heavy dew lasting well into mid-day

Susceptible crop stage: anthesis (flowering), best observed when yellow anthers are peeking out of the center spikelets on most of the heads in a field.

Areas in RED on the risk map are considered to be at "High Risk" for infection and scab development. Weather has likely been wet in the past week with temperatures generally in the favorable range. The forecast for the next 48-72 hours may have also factored into the risk assessment. If crops are flowering in these areas, they are likely to be infected by the scab fungus. Treatment with a properly timed fungicide is recommended while the crop is in full flower. Early treatments (applied to partially-emerged heads) will not be effective at scab suppression. Late treatments (when head is past flowering stage) will also not prevent infection.

Areas in YELLOW on the risk map are considered to be at "Moderate Risk" for infection and scab development. Past/forecasted weather across the area has been generally less favorable for infection than for high-risk areas. Infection may still occur, but should be more limited than for other areas. Treatment would be recommended only if the growers risk tolerance is low (e.g.: due to a high-risk crop such as durum or hard white wheat). Local conditions do vary, and if your fields have received greater levels of precipitation than the surrounding area, or tend to remain wet longer than others in the area, you may also be at 'high-risk'.

Areas in BLUE on the risk map are considered to be at "Low Risk" for infection and scab development. Past/forecasted weather across the area is considered to be generally unfavorable for disease development. As local conditions do vary, it is important to understand the precipitation and temperature for your own growing areas.

The risk of scab development in these areas is unknown at this time.