← All problems
Fungal disease
Common leaf spot
Mycosphaerella fragariae
The one with the white centre. Widely reported and widely over-treated — on an established crop it is often cosmetic.
What you see
- 01Small deep purple, round to irregular spots on the upper leaf surface, 1–2 mm across
- 02On older leaves the centre turns tan, then grey or white, ringed by a reddish-purple to rusty-brown border
- 03On young leaves spots stay light brown without the pale centre
- 04Elongated lesions on petioles, stolons, calyxes and fruit trusses
What brings it on
Wet foliage and moderate temperatures. Also called Ramularia leaf spot, bird's-eye spot or white spot in older literature.
Why it costs money
On leaves it is usually tolerable. The cost is on petioles, stolons and trusses, where lesions interfere with water transport, weaken the structure and open the way to secondary organisms. Calyx spotting also downgrades otherwise good fruit.
What to do
- Learn to separate it from leaf scorch — the white centre is the tell, and the two need different levels of concern
- Keep foliage dry where irrigation allows
- Remove old infected leaves at renovation
Spray strategy. Do not spray on the basis of leaf spotting alone. Judge on how much petiole, stolon and calyx involvement you have, since that is what actually costs you.
Also check