Impact of burial on survival of Ascochyta lentis on lentil residue

In the fall of 1994, a trial was initiated to assess the survival of Ascoch yta lentis Vassil. on naturally infected lentil (Lens culinaris Medik.) res idue buried at 0-, 5- and 10-cm depth in a clay loam soil at Saskatoon, Sas k, Samples were collected and assessed from 1995 to 1998, with six replicat es for each depth x sampling date combination. After collection, the materi al was air dried, divided in half (by mass), and assessed using a plating a nd a bioassay technique. Results from both techniques were similar. Inoculu m levels in the spring of 1995 were almost an order of magnitude higher tha n the previous fall, indicating that the pathogen had spread in the infecte d residue. Inoculum potential declined slowly over the course of the trial, but the pathogen was still present and infectious (although at low levels) in the residue almost 4 years after harvest. There was a consistent patter n of seasonal fluctuation in the level of A. lentis in infected residue: le vels were higher in spring than in the previous fall. Contrary to previous reports, burial did not have a substantial impact on the long-term survival of A. lentis.