Strawberry Leaf Spot
Risk near you, next 48h
See whether your local forecast favours this disease right now.
When it strikes
Watch it before you act
At this level the damage rarely costs the crop. Note the date, check twice a week, and act only if it reaches new growth or the weather turns favourable for it.
Rain and irrigation splash
Water splashing off soil and infected leaves carries it upward and along the row. Watering at the base and mulching the soil surface break the route.
It carries over to next season in soil, debris or seed — which is why rotation matters here, not just treatment.
Hot compost only
A heap that reaches and holds 55–65°C throughout will destroy it. A cool corner heap will not, and will return the problem to the beds with the finished compost.
When and where to look
Scout the planting while temperatures hold between 15°C and 25°C, with humidity above 85%, after rain or heavy dew, while the leaves are still wet. Risk builds after roughly 8 unbroken hours of those conditions, so the morning after such a night is the moment to look.
Rule these out first
Same category, and at least one host crop in common — so they are genuinely confusable in the same part of the garden.
The signs that lead here
Full problem lists for these crops
About
Leaf spot (Mycosphaerella fragariae) is the commonest leaf disease of strawberries and is almost universal in older beds. It rarely reduces the crop on its own, but a heavy attack weakens the plant going into winter and reduces next season’s flowering.
Symptoms
Small round spots with deep purple margins and a pale grey or white centre, scattered across the older leaves. Spots may also appear on stalks and on the calyx of the fruit. Badly spotted leaves yellow and die.
Organic Treatment
Cut off and remove all the old foliage immediately after the last picking — clearing the leaves takes most of the inoculum out of the bed in one go. Do not compost the trimmings, and mulch fresh straw before the next season.
Chemical Treatment
Rarely justified in a garden. Where beds are badly affected, a copper or myclobutanil spray applied after renovation and again at early growth in spring will reduce it.
Prevention
Renew the bed every three years from clean runners, space plants for airflow, water at the base in the morning, and never leave old leaves lying between plants over winter.
Crops at risk
Related problems
Strawberry Leaf Spot risk by location
Each location has a month-by-month profile computed from the weather archive: how many hours a year actually meet this disease’s thresholds.