EFFECT OF PLANT-AGE, LEAF POSITION AND LEAF SEGMENT ON INFECTION OF LEEK BY LEEK RUST, PUCCINIA-ALLII

Potted plants of leek, Allium porrum cv. Musselburgh, were inoculated with urediniospores of leek rust, Puccinia alliii, and maintained for 21 days in a controlled‐environment cabinet. Mean pustule density, mean pustule length and mean colony length all decreased with increasing plant age, from 2 to 8 months old, and there was a tendency for latent period to increase with increasing plant age. On 8‐month‐old plants pustule development continued over 21 days post‐inoculation but the proportion of flecks developing into pustules remained below 50%. In non‐tip portions of inoculated leaves, mean pustule density increased and mean pustule length decreased from upper to lower leaves in the standing crop. Tip portions of leaves either varied less in resistance with leaf position or showed random variation. Copyright © 1990, Wiley Blackwell. All rights reserved