Diseases
Leaf spot disease
Identify Leaf spot disease: symptoms, possible causes, prevention, and practical actions for 15 affected plants. Small, round to irregular spots on leaves
Editorial diagnosis
Diagnosis overview
Leaf spot diseases are caused by different pathogens that damage leaf tissue and may cause leaf drop.
In gardens, Leaf spot disease can occur on plants including Aronia, Tree spinach, Leafy Goosefoot, peanut. In the available profiles, it is linked mainly with Berries, Herbs, Leafy vegetables.
The recorded risk level is low. Conditions that favour it include Wet weather or prolonged leaf wetness, Dense planting and poor airflow, Susceptible cultivars. It becomes serious when many leaves die early.
Compare upper and lower leaf surfaces, the boundary between healthy and damaged tissue, and spread after wet weather. Coatings, spores, or progressive rot support a disease diagnosis.
A common mistake is to identify a disease from one spot alone; weather, spread, and pathogen structures also need to fit.
At a glance
Plants
15
Category
Berries, Herbs, Leafy vegetables, Legumes, Ornamentals
Risk
low
Scientific name
Alternaria spp., Cercospora spp.
Typical signs
- Brown or black spots
- Possible yellow halo
- Early leaf drop
- Often on older leaves
Possible confusion
- Growing problem: Growing problems are usually linked to water, light, temperature, or soil and do not show pathogen growth, pustules, or progressive infection patterns.
- Nutrient deficiency: Deficiency patterns are often more regular and follow leaf age or veins. Diseases more often show spots, coatings, rot, wilting, or pathogen structures.
Immediate actions
- Remove affected plant parts
- Improve airflow
- Avoid overhead watering
- Keep tools clean
- Remove heavily infected plant residues
Prevention
- Use suitable spacing
- Follow crop rotation
- Choose robust cultivars
- Keep leaves dry
- Support soil structure and plant vigour
Affected plants
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