Frost can cause serious yield and quality losses from stem elongation through flowering and grain fill. Damage is not always obvious straight away, so inspect several areas of each paddock and allow time for symptoms to develop before making major decisions.
What to do after a frost
Check low-lying and known frost-prone areas first, then compare them with less-affected parts of the paddock. Look for water-soaked, discoloured or bleached tissue, damaged stems and heads, and poor grain set. Revisit the crop over the following days, map the affected area before deciding to retain, graze, cut for hay or manage the crop another way.
WA research has shown an ice-nucleating bacteria, including Pseudomonas syringae, can increase frost severity by helping ice form at relatively mild sub-zero temperatures. The bacteria is commonly found on retained stubble, crop residue and older lower-canopy leaves, and can also arrive with rainfall before a frost. The bacteria act during the frost event; the resulting injury becomes visible after thawing as water-soaked tissue and, over the following days, bleached leaves, stems, heads or reproductive tissue. Field trials found targeted bactericide applications temporarily reduced bacterial ice-nucleating activity and lowered leaf-freezing potential by up to about 3°C, but the mild trial seasons did not produce a clear reduction in crop damage or a yield benefit. More research is required before this becomes a proven grower treatment. Further information is available in the WA Government article “Grains Research Update 2026: Frost mitigation spray treatments show promise”.
Useful resources
DPIRD frost page — the main WA hub for frost information, tools and current research.
Managing frost risks — practical steps to reduce exposure before and during the season.
Management options for frosted crops — guidance for assessing damage and weighing up what to do next.
Cereal frost guide and canola and pulses frost guide — crop-specific identification information.
Canola genetics research — work supporting the development of more frost-resistant varieties.
For a practical discussion on assessing damage, crop recovery and next steps, listen to DPIRD frost researcher Brenton Leske on Apple Podcasts or Spotify.
Key message: Assess first, avoid rushed decisions. Symptoms and likely yield effects can vary across a paddock, even when temperatures appear similar.
