Grain Temperature Targets for Insect Control in Storage
Cooling grain is one of the most effective ways to slow stored-grain insects. Here are the temperature bands that matter and how to reach them.
SiloSense IQ ·
Stored-grain insects are cold-blooded. Their development speed is set by the temperature of the grain they live in. That gives you a lever: control the grain temperature and you control how fast an infestation can grow.
The temperature bands
As a general guide for the main stored-grain pests in Australia:
| Grain temperature | Insect activity |
|---|---|
| Above 30°C | Ideal for many species — populations can grow very quickly. |
| 20–30°C | Development is fast; infestations build within weeks. |
| 15–20°C | Development slows considerably. |
| Below 15°C | Development of most species stops or nearly stops. |
GRDC grain storage guidance commonly gives below 20°C as the practical target for aerated storage, with below 15°C stopping most species. Different species have different limits, and insects aren’t killed at these temperatures — they’re slowed. When grain warms up again, they resume.
Why harvest temperature is the risk
Grain often comes off the header in the 30s °C. Left unaerated, it can sit in that ideal range for weeks, because grain insulates so well. That’s exactly when infestations take hold.
Cooling aeration is designed to take that heat out quickly. Even modest airflow can bring grain from harvest temperatures into the low 20s or below, if the fans run on cool air.
Reaching and holding the target
- Forced run after harvest. Push field heat out straight away.
- Run on cool air. Night air in autumn is usually your best cooling resource. Air needs to be meaningfully cooler than the grain to make progress.
- Get the cooling front all the way through. Watch the top sensor level — it’s the last to cool.
- Maintain. Once cool, short regular runs on suitable air stop pockets warming back up.
Cooling doesn’t replace hygiene
Temperature control is one part of insect management. It works best alongside:
- clean silos and equipment before harvest;
- removing fines and residues where insects breed;
- monitoring with sampling and traps;
- treatment when needed, following label directions and resistance-management advice.
How SiloSense helps
SiloSense IQ shows grain temperature at every level, so you know whether the whole silo has reached your target — not just the bottom.
SiloSense IQ+ puts these bands to work: it compares grain temperature with insect-risk bands at 15, 20 and 30°C, and chooses when to run aeration to bring grain down and hold it there, while guarding against air that would add moisture.
Request a demo to see insect-risk bands on a live silo.