United Kingdom
August 2013
HGCA PROJECT REPORT 512
Importance and management of Verticillium wilt in winter oilseed rape
by
Peter Gladders1, Faye Ritchie2, Dez Barbara3, John Clarkson3, Tracey Chantry4, Moray Taylor4 and Judith Turner4
1ADAS Boxworth, Boxworth, Cambridge CB23 4NN,
2ADAS Rosemaund, Preston Wynne, Hereford HR1 3PG
3 Warwick Crop Centre, University of Warwick, Wellesbourne Campus, Wellesbourne, Warwick CV35 9EF
4FERA, Sand Hutton, York YO41 1LZ
August 2013
Abstract
The aim of this project was to establish the importance of verticillium wilt in winter oilseed rape and carry out initial work on varietal resistance and the impact of agronomic factors.
Between 2009 and 2011, verticillium wilt was confirmed in 16% of 292 randomly selected crops of winter oilseed rape that were sampled in late June. About 5% of crops had more than 30% of plants affected and the average level of verticillium wilt in England was 3.3% of plants affected. Verticillium wilt was found most frequently in eastern England, but it occurred in all regions and as far north as Yorkshire.
There were significant differences in verticillium wilt severity between winter oilseed rape varieties with widely grown varieties such as Castille, Excalibur and Es Astrid being amongst the most susceptible. The varieties Catana, Oracle, Alienor and Compass were considered to have useful levels of resistance though further testing of varieties is required to substantiate these initial results.
The effect of verticillium wilt on yield was investigated by hand harvesting plants from four commercial crops with different severities of verticillium wilt. Yield loss was evident when verticillium wilt was severe and was due to decreased thousand seed weight, estimated at 12-24% in severely affected plants. Experiments on date of sowing and soil temperature, together with survey data, indicated that verticillium wilt can develop under a wide range of temperature conditions. Symptoms of verticillium wilt appear to be more severe when plants are not growing vigorously or are under stress. Thus any potential benefit from delaying sowing to reduce verticillium infection is offset by greater symptom expression on small plants.
Efforts to develop a DNA-based soil diagnostic test for Verticillium longisporum were unsuccessful, as techniques were either not sufficiently sensitive or specific enough for testing infested soils. New PCR primers, based on genome sequences for Verticillium species, are now available for testing.
The project has raised awareness of this ‘new disease’ and provided the first data on the distribution and importance of verticillium wilt in winter oilseed rape. The pathogen is clearly well established in some fields, particularly in eastern England and it is capable of causing yield loss in some years. There is now considerable interest from breeders and agronomists in testing varieties for resistance to verticillium wilt and this should be extended so that national resistance ratings can be produced. In the absence of a soil test, growers and agronomists should monitor crops visually for verticillium wilt and be prepared to adjust varieties and rotations where there is a threat to yield.
HGCA Project Number: RD-2009-3618
PR512 Final Report
PR512 Project Summary
Species
