A substance used to kill or prevent the growth of fungi and fungal spores. Organic options include copper hydroxide, sulphur, and neem oil. Overuse can damage beneficial soil fungi.
Fungicides are essential tools in Australian gardening, particularly in tropical and subtropical zones where warm, moist conditions favour fungal growth. They work by either preventing fungal spores from germinating (preventative fungicides) or stopping established infections from spreading (curative fungicides). Common types include sulphur-based products, available at Bunnings, which work well for powdery mildew on roses and grapes, and copper fungicides, effective against fungal leaf diseases. Organic options like neem oil and potassium bicarbonate suit gardeners preferring chemical-free approaches. Timing is crucial—apply fungicides during spring and autumn when many fungal diseases emerge, and before summer's high humidity creates ideal conditions for infection. Always follow label directions, as overuse can harm beneficial insects and create fungicide-resistant fungal populations. Combine fungicide applications with good garden hygiene: remove infected leaves, improve air circulation, and avoid overhead watering. In cooler southern zones, fungal pressure reduces significantly during winter, so fungicides are mainly needed in warmer months. For established fungal problems in susceptible plants, consider preventative spraying every 2-3 weeks during high-risk seasons rather than waiting for visible disease symptoms.