Oilseed rape in the rotation

1. January 2012 Oilseed rape in the rotation Faye Ritchie, ADAS Rosemaund

2. What drives rotations? Economics – best margins Soil type (tradition) – what crops can be grown well (and sold) Pest and disease control – especially soil-borne organisms Weed control Politics – set-aside requirements etc Biodiversity Fertility building – especially organic systems Other problems – weather, late harvest, crop failure

3. Rotational issues • WOSR yields – rotation – rooting • Soil-borne disease threats – and interventions - principles - examples • Other disease issues • Conclusions

4. Impact of previous cropping on winter oilseed rape yieldsHGCA project 2922 – led by Ron Stobart, NIAB-TAG Trial location; NIAB-TAG Morley farm, Norfolk four replicate trial drilled on large plots variety Winner (used for the entire trial series) General agronomy prophylactic inputs consistent with local best practice Trial establishment (ideal) OSR cv Winner, typically drilled in early September 1st wheat cv Brompton, typically drilled in the second half of September 2nd (and later) wheat cv Brompton, typically drilled in mid October

5. Project treatment listing

6. OSR Rotational position and yield (t/ha) (Mean of 2006 – 2011 data)

7. Decline in OSR yield and rotational frequency(Mean of 2006 – 2011 data)

8. WW Rotational position and yield (t/ha) (Mean of 2006 – 2011 data)

9. Yields and outputs (average data) NB Data for longer rotations not provided by this project

10. Key messages Results clearly highlight rotational impacts on crop performance yield penalties with associated financial implications from close rotations Results to date demonstrate reduced early vigour volunteers issues (crop competition or early season disease) other disease problems (eg stem canker) potential reduction in (cumulative) flowering period evidence that closer rotations are impacting on components for yield and yield drivers (seed development and rooting) Potential pathogens e.g.Olpidium brassicae and Pyrenochaeta sp. are being investigated TSB funded research is starting to examine management options

11. Rooting of OSR - Effects of June rainfall on yield at Boxworth Where rooting is limited, yield is likely to be linked to rainfall

12. Rooting at depth improved particularly by metconazole PGR in spring and correlated with yieldADAS Boxworth 2005

13. Metconazole effects on rooting Rooting data from 6 field trials Applications from pre-green bud (GS3,1) to late green bud (GS3,6) Spring applications increased root length density from 0.48 to 0.60 cm/cm3 (40-100cm depth) Estimated additional water uptake of 6-9 mm Estimated additional yield in dry year of 0.22 – 0.34 t/ha

14. Risk of drought affecting yield • Rainfall for 1986-2008 • 5 regions • 3 soil types • On heavy & medium soils the risk of drought was 1 yr in 2 to 1 yr in 3 • With metconazole the risk of drought was 1 yr in 5

15. Soil-borne diseases and rotation Pathogen increases in a susceptible crop and then declines under non-susceptible crops. Use extended rotations so that pathogen population declines to below threshold for economic damage. Many soil-borne pathogens are capable of long-term survival – interventions are required as long crop rotations may be impractical (>10 years) Where is threshold?

16. Changes in Verticillium populations in relation to potato crop in 2003. No decrease in 6yr rotation March 2003 14.8 cfu/g January 2009 12.5 cfu/g Potato Council Project R/328

17. Soil-borne oilseed rape diseases – severe clubroot

18. Sclerotinia surveys WOSR England 1986-2011 CropMonitor data

19. Products stretched in 2010 by late flowering infection (early June) - Herefordshire

20. Responses c. 1 t/ha from all products, Herefordshire 2010

21. SkleroPro Infection model Criteria: • Minimum requirements 7ºC and 80% RH for 23hr Use to identify infection events in England Koch et al., 2006

22. Fungicide persistence 3 weeks – needed 2 sprays in 2010 Sklero Pro infection events AFD

23. Sclerotinia and rotations • Higher risk where OSR grown in short rotations or in rotations with other susceptible crops - Peas, potatoes, carrots and other veg crops • Sclerotia are long-lived if buried deeply. • Fungicides very effective (for a soil-borne disease)

24. Verticillium wilt (V. longisporum) symptoms – can we manage this disease threat?

25. Verticillium wilt First confirmed in UK in 2007 Pathogen is Verticillium longisporum – specific for crucifers (mainly brassicas) – first described 1997 Important in other parts of Europe with up to 50% yield loss

26. Disease cycle of OSR verticillium wilt Plant debris or soil from nearby infested fields How much inoculum are you producing?

27. Use resistance in varieties LSD 10.2

28. Improving verticillium management – 2012 actions • Monitor crops pre-harvest – how much verticillium is present? • Found in all regions - more in south and east • Consider variety choice • Be prepared to extend rotations to at least 1 in 4

29. Rotations – spatial implications • If crops are grown in short rotations, new crops will be close to the previous year’s stubble and subject to spore transfer from crop residues and volunteers. • Disease gradients can be steep for some diseases (eg Phoma leaf spot).

30. Light leaf spot – high risk for 2012

31. Light leaf spot in spring has been increasing for the last 6 years

32. Regional light leaf spot risk Increased risk Similar risk 2010/2011 2011/2012 Source: http://www3.res.bbsrc.ac.uk/leafspot/forecast/Default.htm

33. Large yield benefits from varieties with good light leaf spot resistance Castille 4.19 Cuillin 4.84 LSD =0.2 (KWS data 2010 N Yorks)

34. HGCA Light leaf spot control not easy - 2011 LSD = 0.47

35. HGCA Light leaf spot fungicides and yield, N Yorks 2011 Treated yield 4.97 v untreated 4.39 P<0.001

36. Implications for light leaf spot control • High risk in 2012 • Better yield performance where second treatments applied in February • Control difficult – need to use more resistant varieties. • Product and dose differences were identified - prothioconazole gave best economic performance in first HGCA project; tebuconazole and flusilazole still performing well • Concerns about azole resistance • Highly resistant varieties – Palace, Cuillin, Cracker, Catana

37. Conclusions • Rotations are driven by economics • Disease problems can emerge on short rotations but solutions are available to manage many of them. • New diagnostic tools should help quantify problems in future and guide management decisions.

38. Thank you Visit www.hgca.com/diseasecontrol for more information

39. Oilseed RapeUpdate on new RL varieties and disease management Paul Gosling Research & KT Manager (Agronomy)

40. Recommended list new additions for 2012

41. Oilseed rape * The spring OSR list is descriptive

42. Spring varieties New Yield

43. Winter varieties

44. Seasonal variation in oilseed rape E/W yields (controls & new) Average yield gain worth £140/ha based OSR @ £350/tonne

45. Restored hybrid varieties New Resistance DK Expower contains the RLM7 resistance gene giving good resistance to Phoma

46. Conventional varieties New Agronomy DK Camelot is an earlier maturing variety

47. Semi-dwarf RH - East/West New Yield Agronomy Thorin is a high yielding semi dwarf variety with short stiff stems

48. Clubroot resistant RH New Yield Resistance Cracker provides growers with a combination of light leaf spot resistance and clubroot resistance

49. New information on disease management

50. Clubroot RD-2007-3373 Management of clubroot (Plasmodiophora brassicae) in winter oilseed rape RD-2008-3525 Brassicas: Further Development of “in field” tests for resting spores of clubroot and the development of clubroot control based on detection Healthy Diseased