Apple Scab: Identify, Prevent, and Treat

What Is Apple Scab?

Apple Scab (Venturia inaequalis) is a fungal disease that attacks leaves and fruit during cool, wet spring weather. Spores overwinter in fallen leaves and are released when temperatures stay between 6°C and 24°C with prolonged leaf wetness.

How to Identify It

Look for olive-green to brown spots on the undersides of young leaves. As the season progresses, spots turn black and velvety. On fruit, you'll see raised, corky scabs — fruit may crack and deform if infected early.

Prevention

Rake and burn fallen leaves every autumn. Spray urea (5%) in late autumn to speed leaf decomposition and destroy overwintering spores. Ensure tree spacing allows good airflow. Begin preventive fungicide sprays at green-tip stage.

Treatment

Use systemic fungicides like Myclobutanil or Tebuconazole at 10–14 day intervals during high-risk periods. Rotate chemical groups to prevent resistance. After heavy infection, copper-based sprays help slow further spread.