Fungal
Alternaria Blight
A fungal disease causing dark bullseye-patterned spots on leaves and stems, often triggering early defoliation and reducing yield in warm, wet conditions.
Symptoms to Look For
- Dark brown circular spots with concentric ring patterns on older leaves
- Yellow halos surrounding spots, causing premature leaf yellowing and drop
- Dark sunken lesions on fruit and stem collars in severe cases
Affected Plants
TomatoPotatoCarrotBrassicaPepperBeetrootOnion
Organic Solutions
Copper spray
Apply copper-based fungicide spray preventatively from transplanting, repeating every 7 - 14 days during warm wet weather.
Remove infected leaves
Strip and destroy spotted leaves as soon as they appear to reduce spore load and slow the spread up the plant.
Prevention
- Rotate crops for at least 3 years to prevent spore build-up in the soil
- Avoid overhead irrigation and water at the base of plants in the morning
- Choose resistant varieties where catalogue listings indicate Alternaria resistance
Garden, by Willowbottom recommends only organic, wildlife-friendly solutions. No synthetic pesticides, no harmful chemicals - ever.