Response of lentil cultivars to Sclerotinia white mold and Botrytis grey mold infection under irrigated and dryland conditions

Abstract

Diseases such as Sclerotinia white mold (SWM), caused by the fungus Sclerotinia sclerotiorum (Lib.) de Bary, and Botrytis grey mold (BGM), caused by the fungus Botrytis cinerea Pers., may be limiting factors for lentil production in wetter areas of Alberta, Canada. Field trials were conducted at the Lethbridge Research and Development Centre from 2013 to 2015 to evaluate the response of lentil cultivars to SWM and BGM and yield impacts. Ten lentil cultivars from five market classes were evaluated under irrigated and dryland plots with two planting densities (120 and 160 plants·m−2). Year and irrigation had the largest effect on disease incidence, with highest SWM incidence occurring under irrigation in 2013, followed by 2014 and 2015. Conversely, BGM incidence under irrigation was highest in 2015 and lowest in 2013, but levels were lower than SWM. Significantly (P < 0.05) lower disease incidences were observed in dryland plots, which also produced higher yield than irrigated plots. Cultivars varied significantly in SWM incidence and yield under irrigated and dryland conditions, perhaps due to variable disease pressure, but there was no consistent trend in cultivar performance. BGM incidence was similar in cultivars, but differed among years. These findings indicate that SWM may be a limiting factor to lentil production in wetter areas, as the 10 cultivars from five market classes tested were all highly susceptible to SWM.