Ramularia leaf spot of artichoke

Symptoms

Small (3-8mm) angular brown-grey leaf spots with yellow halos, white powdery sporulation on lesion undersides in moist conditions, severe infection causes premature senescence of outer leaves, head quality reduced + bract discoloration in heavy attacks.

Plants affected

• globe artichoke

Easily confused with

• olive Verticillium wilt

  How to tell them apart: Look for discrete, well-delimited leaf spots on the artichoke foliage: small angular-to-rounded lesions, pale tan to greyish-brown centres often surrounded by a darker or yellow halo. In humid conditions a fine whitish-grey fuzz (sporulation) may appear on the underside of the spots. Damage stays clearly spotty and leaf-localised, the spots enlarge and coalesce but the vascular tissue of cut stems and petioles remains clean and white. The plant does not wilt as a whole; older outer leaves show the spots first. Verticillium wilt is diffuse, not spotty: whole leaf sectors turn pale with interveinal chlorosis (yellowing between the veins) and dry to a marginal scorch, frequently on one side of the plant or one half of a leaf. Affected outer leaves wilt and collapse during the heat of the day. The decisive sign is internal: slice a stem or large petiole lengthwise and look for brown to greyish vascular streaking. No discrete spots and no fuzzy sporulation on the leaf surface.

Common questions

How do I recognise Ramularia leaf spot of artichoke on globe artichoke?

Small (3-8mm) angular brown-grey leaf spots with yellow halos, white powdery sporulation on lesion undersides in moist conditions, severe infection causes premature senescence of outer leaves, head quality reduced + bract discoloration in heavy attacks.

Do I have to report Ramularia leaf spot of artichoke?

No. Ramularia leaf spot of artichoke is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.

How is Ramularia leaf spot of artichoke treated?

Mainly with biological and cultural measures — removing affected material, changing the conditions that favour it, and treating with agents approved in your country. The exact steps and their timing depend on the plant, the season and where you live: Dr. Phyto works them out in a free diagnosis.