Management of Botrytis grey mould caused by Botrytis cinerea in lentil using boscalid fungicide

Abstract

Under cool and wet conditions, high levels of botrytis grey mould (BGM) can occur on lentil in western Canada. Identification of local Botrytis isolates from lentil based on conidial morphology (N = 74) and sequence analysis (N = 5) indicated that B. cinerea was the predominant cause of BGM in this region. Eight field experiments at two sites (Saskatoon, SK and Outlook, SK) over two seasons were conducted to evaluate the optimal timing of the fungicide boscalid for the control of BGM in the lentil cultivar ‘CDC Grandora’. Weather conditions limited disease development in one year, but moderate levels were observed in four experiments in the other year. In all experiments, a single application at mid-flower in early-seeded experiments and at early flower in late-seeded experiments was as efficacious as a double or triple application of boscalid. There were no differences among double application treatments, and at Outlook they were all as efficacious in lowering BGM as the triple application. Despite some differences in BGM severity among fungicide applications, none of the treatments had an effect on yield or seed infection, and there was no correlation between petal colonization by B. cinerea and BGM disease severity under the study conditions.