Purple blotch of leeks caused by Alternaria porri.

Gladders, P.

The article discusses the purple blotch of leeks caused by Alternaria porri. In October 1980, purple spots on leaves and stems were reported in a mature crop of leeks, cv. Snowstar, on peat oil in Cambridgeshire, England. The disorder was largely confined to a small area of the crop near an unsheltered edge of the field. Elliptical purple lesions, up to 4 cm long and bearing black, sporulating conidiophores, were very conspicuous on the stems and spathes of plants which had run to seed. Up to 10 per cent of leaf area was affected by elliptical, white lesions 1-4 cm long, often with a pale purple centre. The larger lesions had concentric dark and light zones where sporulation of a fungus identified as Altemaria poni (Ellis) Cif. was heavy or sparse respectively. The identification was confirmed by S. M. Francis at the Commonwealth Mycological Institute. Similar leaf symptoms have also been found in Cambridgeshire on about 25 per cent of leek plants, cvs Splendid and Goliath, raised from seedlings in peat blocks. Again there was sporulation of 1 porri.

CAMBRIDGESHIRE (England); ENGLAND; LEEK; ALTERNARIA; PLANT diseases; AGRICULTURAL pests

Plant Pathology, 1981, Vol 30, Issue 1, p61

0032-0862

Academic Journal

10.1111/j.1365-3059.1981.tb01228.x