Pea and Lentil Disease Survey 2016 Season Summary (09/15/16)
Pea and Lentil Disease Survey 2016 Season Summary
A new scouting program for peas and lentils in northwest North Dakota was successful at detecting several diseases this summer and determining their distribution across the region. Support was provided by the Northern Pulse Growers Association for a full time crop scout (Adam Carlson, NDSU) to survey fields in Williams, Divide, Mountrail, McKenzie and Burke Counties from late May to mid-August. Below is a summary of what was observed in pea and lentil fields this season.
Lentils: Ascochyta Blight and Anthracnose were found in most fields scouted, however severity levels remained low over the course of the season (Fig 1). In North Dakota, Stemphylium Blight of lentils typically develops in the last third of the season from late bloom through pod fill. During this time period, low levels of Stemphylium were observed in most fields scouted. White mold was assessed at crop maturity, and was found sporadically at low to moderate levels (Fig 2). Fields were also assessed for Botrytis Gray Mold, however this disease was only identified in one field this season.
Pea: Ascochyta Blight was found in most fields scouted but severity levels were low, limited to only a few scattered lesions per leaf. Bacterial Blight increased in incidence over the course of June and was found in all fields scouted in mid-July, most likely due to frequent precipitation, but again severity remained low (Fig 3). Powdery Mildew was identified in central and north central McKenzie County (Fig 4), and was severe at the WREC pea variety trial planted near Arnegard. White Mold was found in central Williams County and north central Divide County (Fig 4).
Samples were collected from pea and lentil fields for analysis of root rot over the course of the entire growing season. Root samples were assessed for root rot severity and the presence of the root rot pathogens Rhizoctonia solani, Pythium sp., Fusarium sp. and Aphanomyces euteiches (Dr. Julie Pasche and Dr. Kim Zitnick-Anderson, NDSU).
Lentils: Root rot symptoms were mild in May, but severe in some fields by early to mid-June (Fig 5). Fusarium sp. and Pythium sp. were isolated from symptomatic roots. One field in southern Williams County was also positive for Aphanomyces. Rhizoctonia solani was not present in any samples. 170 root rot samples were analyzed in total.
Peas: Over 50 root rot samples were taken from pea fields and root rot was either absent or mild in most samples tested. However, five fields contained moderate to severe root rot late in the season at the R5-R6 stage. Pythium sp. and Fusarium sp. were most commonly isolated from symptomatic roots. No Aphanomyces or Rhizoctonia solani were isolated from any sample.
Plant Pathologist, NDSU Williston Research Extension Center
Assistant Professor, NDSU
Department of Plant Pathology
Post-Doctoral Research Associate, NDSU Department of Plant Pathology