Crop Intelligence Insight:
Disease Risk
Fungicide Decisions:
- Fungicide Decisions are some of the most difficult you make on the farm each year.
- Your Field Connect weather station and the Crop Intelligence app can provide supporting information to help make fungicide decisions.
- Environmental Conditions play an important role in disease risk.
- Yield Potential can bring clarity to the economics of the decision.
Disease Risk:
Susceptible Host:
Susceptible Host:
- Varietal resistance ratings
- Crop stage
- Field history and rotation
- Regional risk
- Pathogen biology
- Current environmental conditions.
- Future environmental conditions (weather forecast).
Environmental Conditions:
Field Connect Data
- Rain: rain events in the two weeks prior to potential spray timing should be considered. Even small rain events <5 mm can contribute to disease risk.
- Soil Moisture: moist soil at the surface increases disease risk.
- Air Temperature: moderate temperatures 15-25?C are ideal for most pathogens.
- Soil Temperature: soil temperature around 20?C.
- Relative Humidity: greater that 50%.
- Leaf Wetness: values above 5K indicate moisture in the crop canopy. When leaf wetness is sustained for >12 hours – disease risk increases.
Yield Potential:
Crop Intelligence Data
Water Driven Yield Potential can provide an indication of how much yield potential there is to preserve.
Leaf Wetness Sensor:
- Quantifies the amount of water on its surface, which can be a good approximation of the amount of water on the leaves in the canopy.
- A leaf is considered dry around 4200 and at 5000 there is moisture within the canopy.
- Greater than 5000 over 12hrs indicates increased disease risk
Canola Risk Assessment:
- The Canola Council has many useful resources to assist in fungicide decision making.
- Results suggest 40 or higher will likely see benefits but dependent on product and commodity pricing.
- www.canolacouncil.org/media/516526/canola_disease_scouting.pdf
FHB Risk Assessment:
- Precipitation or high humidity for at least 12 hours.
- Temperatures favouring infection range from 16 to 30°C.
- Spores are spread by rain-splash and wind.
- FHB infection is most likely to occur during July when the florets are open during flowering, allowing spores to come into contact with the floret.
- https://www.saskatchewan.ca/business/agriculture-natural-resources-and-industry/agribusiness-farmers-and-ranchers/crops-and-irrigation/disease/fusarium-head-blight
- SaskWheat has a weather-based fusarium head blight (FHB) risk maps that can be useful to determine risk.
- http://www.saskwheat.ca/producer-info/fusarium-risk-assessment-map/
Pulse Risk Assessment:
In pulses it is important to consider:
- Crop canopy/plant stand.
- Leaf wetness & humidity.
- Weather forecast.
- Field history.
- Plant symptomology.
- SaskPulse Growers produces a variety of fact sheets to help manage disease risk in pulse crop.
- http://saskpulse.com/files/newsletters/180501_Fungicide_Decision_Support_Sheet_for_Peas-compressed.pdf
- http://saskpulse.com/files/newsletters/1800601Fungicide_Decision_Support_Sheet_for_Chickpeas-compressed.pdf
- http://saskpulse.com/files/newsletters/180605_Fungicide_Decision_Support_Sheet_for_Lentils-compressed.pdf
Boots on the Ground:
Nothing replaces boots-on-the-ground when assessing disease risk.
- Crop Intelligence and Field Connect can provide supporting information – but the context of what is going on in the field is required to make an informed decision.
- Plant stand and canopy closure.
- Visual appearance – yield potential.
- Visual appearance – disease symptoms.
- Moisture on the soil surface and in the crop canopy.