Impact of burial on survival of Ascochyta lentis on lentil residue

Abstract

In the fall of 1994, a trial was initiated to assess the survival of Ascochyta lentis Vassil. on naturally infected lentil (Lens culinaris Medik.) residue buried at 0-, 5- and 10-cm depth in a clay loam soil at Saskatoon, Sask. Samples were collected and assessed from 1995 to 1998, with six replicates for each depth × sampling date combination. After collection, the material was air dried, divided in half (by mass), and assessed using a plating and a bioassay technique. Results from both techniques were similar. Inoculum levels in the spring of 1995 were almost an order of magnitude higher than the previous fall, indicating that the pathogen had spread in the infected 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 pattern of seasonal fluctuation in the level of A. lentis in infected residue: levels 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.

Keywords:

• tillage management
• ascochyta blight
• Lens culinaris