Frost

Constraint - Frost

When night temperature has dropped below 2 degrees and there is evidence of frost, monitoring of crops is highly recommended.

Symptoms

• May not be obvious for five-seven days after the frost

• Yellow/green discolouration of pods

• Scarring and shrivelling of pods and eventual pod drop can also occur

• Abortion of flowers

• Shrivelling and absence of seeds

Damage

• Crop damage is highly variable

• Canola is most susceptible from flowering to the clear watery phase 

• Compensatory growth can sometimes occur 

• If frosts are very severe/consecutive, whole crops can be lost

Management

There are no treatment options. Management options include planting crop varieties at recommended times to minimise the chance of the flowering window coinciding with increased chance of frosts. Careful consideration of low lying areas and light soil areas when choosing which paddocks to plant to canola can decrease frost damage risk.

Links and Resources

AOF - Frost Description and contributing factors.

BCG - Canola in the Wimmera and Mallee. Frost Page 4. Frost and drought. Published 2008. File size: 444kb

GRDC - Back pocket guide. Frost 12 page PDF. Pages 9 and 10 discuss tolerance, symptoms, and different risk times. Page 11 gives information on similar symptoms. Published 2000, reprinted 2003. File size: 444kb

GRDC - Best Practice Management Guide. Frost Page 27. Time of sowing. Page 28. Table 5.3 Recommended sowing times for south-eastern Australia. Page 30. Early sowing within the frost window is discussed. Page 14. Environmental stresses impacting yield and oil content, frost symptoms discussed. Published 2009. File size: 444kb