1. Verticillium Wilt in the UK Project Update Dr Peter Gladders ADAS UK Ltd

2. Review 1. History in the UK 2. Disease surveys 3. Effects on yield 4. Varieties 5. Management options 1

3. Introduction - Verticillium wilt  First confirmed in UK in 2007  Pathogen is Verticillium longisporum – specific for crucifers (mainly brassicas)  Important in other parts of Europe with up to 50% yield loss  Grey microsclerotia – key diagnostic feature  Look for long streaks right up the stem – phoma similar  Only evident late in season  HGCA Research Review No 72 completed May 2009

4. Disease Cycle of OSR Verticillium Wilt Plant debris or soil from nearby infested fields

5. Disease Survey Samples – Variation by Field & Year Proportion of samples (fields) from Crop Monitor positive for V. longisporum YearSamples examinedPositive% positive 2009951010.5 2010972424.7 20111001212.0 Number of samples with various proportions (%) of stems positive Year0-56-1011-1516-2021-3031-4041-5051-60>60 2009320003011 20101224120120 2011230013003

6. Distribution of Verticillium Wilt 2009-2011 Factors affecting distribution?

7. Rotations and Verticillium Wilt 2010 Previous cropNo. samples% crops% plants Oilseed00.0 Wheat – OSR – Wheat540.03.1 Wheat - Wheat - OSR1330.82.3 Other cereal – Wheat - OSR911.11.0 Other Cereal - Other Cereal - OSR00.0 3 Previous Non OSR Crops2218.2* 4 or More Previous Non OSR Crops4226.2* Other / Unknown info633.3 National9724.73.6 6

8. Yield Impacts  Numerous reports of yield effects when crops ripen prematurely  2012 – significant yield impacts  Single plants harvested from heavily infected crops  Decreased TSW by 12-24% when verticillium affected >50% stem  Further losses if seeds are shed

9. Varieties Differ in their Resistance to Verticillium Wilt LSD 10.2

10. Mean %verticillium by variety - Lincs 2010 & 2011 ( Limited variety experiments but main rankings have been consistent) LSD = 9.9

11. Managing Verticillium Wilt - Options 1. Determine its prevalence on individual farms 2. Good agronomy – a strong plant holds off verticillium 3. Variety choice 4. Extended rotations

12. HGCA Project reference  RD-2009-3618 Importance and management of Verticillium wilt in winter oilseed rape  ADAS UK Ltd, Warwick-HRI, FERA, Farmacy/Hutchinsons