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Early blight
Alternaria solani
Fungal diseaseMedium impact
A common fungal disease that typically appears on older, lower leaves first, causing distinctive concentric ring-patterned lesions. Less aggressive than late blight but can significantly reduce vigour if unchecked.
Currently in peak season - extra vigilance worthwhile.
Key facts
- Type
- Fungal disease
- Active season
- Jun - Oct
- Peak season
- Jul - Sep
- Vulnerable stages
- Growing · Harvesting
- Spread rate
- moderate
- If confirmed
- Act soon
Signs & symptoms
- -dark brown circular spots with concentric rings (target-spot pattern) on older leaves
- -yellowing of the tissue surrounding each lesion
- -gradual loss of lower foliage, working upward through the plant
- -lesions may appear on stems as dark elongated patches
Management
Do now
- -Remove and bin affected leaves - do not compost
- -Avoid wetting foliage when watering
- -Improve airflow around plants by removing crowded growth
Prevention
- -Rotate tomatoes and potatoes to fresh ground each year
- -Space plants at recommended distances to allow airflow
- -Water at the base rather than over the foliage
- -Clear crop debris promptly at the end of the season
Further reading
- -Early blight spreads from the bottom of the plant upward - lower leaves showing symptoms first is characteristic
- -Unlike late blight, it tends to progress slowly and rarely causes complete crop loss in the kitchen garden
- -Plants under stress (drought, nutrient deficiency) are more susceptible