Australia’s northern grain regions are reporting increasing levels of pest resistance to phosphine gas, making hygiene and storage practices more critical than ever. Effective grain protection starts before the first seed is stored. The Cooperative Research Centre for Northern Australia (CRCNA) recently found that several pest species have evolved resistance, particularly in humid and tropical regions, where fumigation is less effective without proper silo sealing.
Understanding Pest Resistance
Insects like grain weevils, rust-red flour beetles, and lesser grain borers can multiply rapidly in warm, poorly ventilated silos. Over time, frequent exposure to phosphine without complete gas sealing has created resistant populations. This presents a major challenge for pest control and grain quality, particularly when infestations go unnoticed until significant damage occurs.
The Importance of Silo Hygiene
Thorough cleaning between harvests is essential. Residual grain, dust, and chaff attract pests, giving them an ideal environment to reproduce. Farmers should empty silos fully and use blowers, vacuums, and brushes to clean joints, seams, and augers. Once cleaned, inspecting for rust or seal damage ensures gas-tight integrity before new grain enters.
Gas-Tight Silos and Pressure Testing
Gas-tight silos certified to AS2628 standards are crucial for maintaining fumigant concentration. Regular pressure testing ensures that seals remain intact and fumigation cycles remain effective. Modern designs include features such as heavy-duty lid seals, precision-ground outlets, and automated pressure maintenance systems to reduce leakage over time.
Integrated Pest Management (IPM)
Combining hygiene with temperature control, aeration, and pest monitoring is key. Aeration fans help maintain cool grain temperatures that slow pest reproduction. Monitoring traps allow for early detection, while rotating fumigants reduces the risk of resistance buildup. Record-keeping also plays a critical role, helping farmers track which treatments are most effective.
Future of Pest Control
With growing resistance to chemical control, researchers are exploring alternative strategies, such as biological control agents and controlled atmosphere systems that use carbon dioxide or nitrogen to suffocate pests. These methods are likely to become more mainstream as environmental regulations tighten.
With pest resistance on the rise, prevention is better than cure. Clean, sealed, and well-maintained silos are every farmer’s best defence.