Ascochyta blight of pea

Symptoms

Small purple-brown lesions on stems near soil line in seedlings, brown leaf spots with dark concentric rings as plant matures, dark sunken lesions on pods + flower clusters, infected seeds show brown discoloration + may carry pathogen to next planting.

Plants affected

• garden pea

Easily confused with

• powdery mildew of pea

  How to tell them apart: Ascochyta pisi (Ascochyta blight) and Erysiphe pisi (pea powdery mildew) both attack pea leaves but differ in the lesion itself. Ascochyta pisi makes discrete, sunken, tan-to-brown spots with a darker reddish-brown rim, often with tiny black dots (pycnidia) in the centre, and the same lesions appear on stems and pods. Erysiphe pisi instead produces a superficial powdery white-to-grey coating that wipes off with a finger, starting as faint pale patches on the upper leaf surface and spreading to cover whole leaves, stems and pods in a dusty film, and it is favoured by warm dry days with cool humid nights rather than the wet conditions Ascochyta needs.

Common questions

How do I recognise Ascochyta blight of pea on garden pea?

Small purple-brown lesions on stems near soil line in seedlings, brown leaf spots with dark concentric rings as plant matures, dark sunken lesions on pods + flower clusters, infected seeds show brown discoloration + may carry pathogen to next planting.

Do I have to report Ascochyta blight of pea?

No. Ascochyta blight of pea is not a notifiable organism, so there is nothing to report to an authority. Treat it as a normal garden problem.

How is Ascochyta blight of pea 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.