Abstract Detail

Host/Plant Pathogen Interactions and Plant Health Management

Chatterton, Syama [1], Harding, Michael [2], Bowness, Robyne [3].

Identification of pathogens associated with root rot of field pea in Alberta.

Late season root rot of field pea, causing wilting and death of mature plants has recently become a serious problem in Alberta. The prevalence and severity of root rots in Alberta pea fields were assessed in July 2013 and 2014. Roots were dug up at each of 10 sampling sites/field, washed and assigned a visual disease severity rating (1=healthy up to 7=dead). Root rot was found in almost all fields surveyed with a mean incidence of 86% in both years, and a mean severity of 3.0 and 3.3 in 2013 and 2014, respectively. However, disease severity differed significantly between regions. The most prominent symptoms included red vascular streaking and dark brown to black rot of the tap root indicative of Fusarium spp., but brown discoloration and cortical decay of lateral roots indicative of Aphanomyces euteiches Drechs. was also observed. Total genomic DNA was extracted from diseased root samples from each field, and amplified with species-specific primers for 10 common Fusarium spp. and A. euteiches. Fungi were also isolated from roots by classical culturing techniques. Results from both plate culturing and PCR assays indicated that F. avenaceum, F. solani, F. redolens and F. oxysporum were primarily associated with Fusarium root rot symptoms. However, relative abundance of each species differed between the two detection methods. Aphanomyces euteiches was detected in six fields in 2013 which was the first record of this pathogen causing root rot of field pea in Alberta. Aphanomyces euteiches was only detected using PCR assays, indicating plate culture techniques will fail to detect, or dramatically under-estimate, the presence and distribution of this pathogen. In 2014, A. euteiches was detected in 45% (n=77) of surveyed fields. Fields in black and thin-black soil zones had the highest detection frequencies, with 85% and 71% of sampled fields positive for A. euteiches, respectively. The high incidence and severity of root rots documented in this survey substantiates the concern that Alberta producers have expressed in recent years, and indicates that further investigations into control strategies and continued monitoring for spread of A. euteiches are necessary.

Related Links:
First report of Aphanomyces root rot of field peas in Alberta

1 - Agriculture and Agri-Food Canada, Science and Technology, 5403 1st Ave. S., Lethbridge, AB, T1J 4B1, Canada
2 - Alberta Agriculture and Rural Development, Crop Diversification Centre South, 301 Horticultural Station Road East, Brooks, AB, T1R 1E6, Canada
3 - Alberta Agriculture and Rural Development, Lacombe Research Centre, 6000 C E Trail, Lacombe, AB, T4L 1W1, Canada

Keywords:
Fusarium
Aphanomyces
field peas
root rot.

Presentation Type: Oral Paper:Papers for Topics
Session: 55
Location: Salon 2/The Shaw Conference Centre
Date: Tuesday, July 28th, 2015
Time: 3:15 PM
Number: 55001
Abstract ID:281
Candidate for Awards:None