Diseases caused by Spongospora subterranea implicated as components of sub-optimum potato yields in New Zealand

Transcription

1 The New Zealand Institute for Plant & Food Research Limited Diseases caused by Spongospora subterranea implicated as components of sub-optimum potato yields in New Zealand Richard Falloon, Sarah Sinton, Farhat Shah, Steven Dellow, Alexandre Michel, Craig Tregurtha & Hamish Brown New Zealand Institute for Plant & Food Research 3 rd International Powdery Scab Workshop Einsiedeln, Switzerland, July 2014

2 Acknowledgements Collaborating researchers: Dr Denis Curtin, Ros Lister, Dr Ruth Butler, Russell Genet, Dr Mark Paget, Dr Ueli Merz Plant pathology, Soil science, Agronomy, Plant breeding, Biometrics Funding agencies: NZ Ministry for Business, Innovation and Employment Potatoes New Zealand Foundation for Arable Research NZ Ministry of Agriculture & Fisheries Sustainable Farming Fund McCain Foods Grower Group NZ Institute for Plant & Food Research Trimble Agricultural Research (Travel) Fellowship

3 Part 1: Spongospora root diseases (Some history) (summary of experimental evidence) Part 2: Multi-year field evaluations ( Yield gap ) Conclusions Falloon, Merz, et al.(2016). Plant Pathology 65:

4 Part 1: Some history 1994: pre-planting fluazinam soil treatment reduced incidence of powdery scab, increased tuber yield by 28% (weight/tuber)

5 Total crop yield % diseased no chemical 19 fluazinam 6 tonnes ha % (increased weight/tuber)

6 Some history 1994: pre-planting fluazinam soil treatment reduced incidence of powdery scab, increased tuber yield by 28% (weight/tuber) 2005: Field-grown potato plants inoculated with S. subterraneahad reduced tuber yields, and reduced water use. cv. Iwa

7 Plant parameters at harvest Mean wgt (kg) tubers per plant Mean no. tubers per plant Mean wgt (g) per tuber No inoculum Inoculum change -42% -26% -22%

8 Soil moisture measurements Time domain reflectometry

9 Water use 1.5 Mean water use difference from average (%) Nov 21-Nov 5-Dec 19-Dec 2-Jan 16-Jan 30-Jan 13-Feb 27-Feb Sample Date Uninoculated Inoculated Irrigation Rain

10 Some history 1994: pre-planting fluazinam soil treatment reduced incidence of powdery scab, increased tuber yield by 28% (weight/tuber) 2005: Field-grown potato plants inoculated with S. subterraneahad reduced tuber yields, and reduced water use. 2011: Greenhouse trial; S. subterraneareduced root function and growth of eight cultivars, with different susceptibilities to tuber powdery scab

11 Glasshouse experiment Eight cultivars uninoculated or inoculated with S. subterranea Very resistant Gladiator, Moonlight Red Rascal Moderately resistant Russet Burbank, Ranger Russet, Umatilla Russet Very susceptible Iwa, Asterix Plant parameters Water use Spongospora severity

12 Shoot Dry Weight Gladiator Moonlight Red Rascal Ranger Russet Russet Burbank Umatilla Russet Iwa Asterix V. Resistant Mod. Resistant V. Susceptible Uninoculated Inoculated Bar is LSD 5% Plant growth g

13 25 Gladiator 25 Ranger Russet Iwa Water use (g) Water use (g) Water use (g) Inoculation Moonlight Inoculation 0 10 Russet 20 Burbank Inoculation Asterix Days after planting 20 Days after planting Days after planting 20 Water use (g) Water use (g) Water use (g) Inoculation Red Rascal Inoculation 0 10 Umatilla 20 30Russet Inoculation Days after planting Days after planting 20 Days after planting Water use (g) Water use (g) un-inoculated inoculated 5 0 Inoculation Inoculation Root function Days after planting Days after planting

14 Final Water Use Gladiator Moonlight Red Rascal Ranger Russet Russet Burbank Umatilla Russet Iwa Asterix V. Resistant Mod. Resistant V. Susceptible Uninoculated Inoculated Bar is LSD 5% Root function g

15 Galls/g Root Dry Weight 450 V. Resistant Mod. Resistant V. Susceptible Gladiator Moonlight Red Rascal Ranger Russet Russet Burbank Umatilla Russet Iwa Asterix Root galls Galls/g

16 Spongosporaroot infection This pathogen adversely affects host plant growth and productivity Deleterious effects occur, both in tuberresistant and tuber-susceptible cultivars Disrupted root function, root galling and tuber powdery scab are separate diseases

17 Part 2: The Yield Gap projects Grower initiated Potato yields becoming uneconomic Average yields 45 to 60 t ha -1 Potential yields >90 t ha -1 (as shown using validated computer-based crop growth model)

18 Multi-year field evaluations Three growing seasons: 2012/13, 2014/15 and 2015/16 Multiple crops (processing and fresh market) Detailed surveys Multiple samplings within each crop Assessment of yield-limiting factors

19 2012/13 -Field survey sites

20 Four fertiliser trials No appreciable increase in yield with doubled rates

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22 11 crops, 10 visits each ( 10 d intervals) (110 crop visits)

23 healthy diseased

24 Major yield-limiting factors Soilborne diseases Soil compaction Inefficient irrigation Weed infestations Variable plant emergence

25 Rhizoctoniastem canker -all 11 crops

26 Rhizoctoniastem canker Long term grass, no history of potatoes Long term cropping, potatoes 5 years previously

27 Soil compaction Height from top of ridge (cm) Distance from centre of ridge (cm) Potato bed profiles - Potato Yield Gap Project Wheel track on left, bed furrow on right Site 7 Seed depth -30 Height from top of ridge (cm) Distance from centre of ridge (cm) Potato bed profiles - Potato Yield Gap Project Wheel track on left, bed furrow on right Site 8 Seed depth -30

28 Yield vsroot vigour

29 Spongosporaroot galls -five crops

30 Inefficient irrigation Fresh tuber yield (t/ha) Irrigation missed Irrigation normal Irrigation missed Irrigation normal Crop 6 Crop 6 Crop 1 Crop 1 Two crops No irrigation Irrigated

31 Weeds (Solanum spp.) Fresh tuber yield (t/ha) weeds weed-free Crop 11 Crop 11 One crop

32 Yield-limiting factors

33 2012/13 crop yields Marketable Yield (t/ha) Site Potential Field

34 2014/15 -Three fields

35 Eight sites in each crop Soil water measurements Regular (3 week intervals) crop sampling and disease assessments Crop yields The New Zealand Institute for Plant & Food Research Limited

36 Site 1 The New Zealand Institute for Plant & Food Research Limited

37 Site 1: deep soil, flat field Soil water content

38 Site 2 The New Zealand Institute for Plant & Food Research Limited

39 Site 2 The New Zealand Institute for Plant & Food Research Limited

40 Site 2: stony soil, dense zone 250 mm, undulating Soil water content

41 Site 3

42 Site 3: two soil types, stony, undulating Soil water content

43 Site 1 Site 2 Site 3 Rhizoctoniastem canker severity score (5 30% coverage)

44 Spongosporaroot and stem galls Spongospora(root galls) Nov Nov Dec-14 7-Jan-15 3-Feb-15 3-Mar Nov Nov Dec-14 7-Jan-15 2-Feb-15 3-Mar-15 1-Dec Dec Jan Feb Mar-15 Perry Pye Tayler Site 1 Site 3 Site 2 Spongospora root galls/plant

45 Site 3: stony soil, Rhizoctoniastem canker, Spongosporaroot galls Tuber fresh weight (t/ha) t/ha yield loss Potential Plot av Oct 28 Oct 17 Nov 7 Dec 27 Dec 16 Jan 5 Feb 25 Feb 17 Mar

46 2015/16-18 fields, 25 crops (fresh market and processing)

47 Rhizoctoniastem canker severity Crops

48 Spongospora root gall severity Crops

49 Powdery scab severity = 5% tuber surface affected Crops

50 Conclusions Spongosporaroot diseases reduce potato plant growth and productivity (Part 1) Soilborne diseases are key causes of sub-optimum potato yields in New Zealand Spongosporaroot diseases are commonly severe in New Zealand (processing) potato crops Spongosporaroot galling has caused widespread occurrence of these diseases Spongosporadiseases are important causes of yield reductions - effective management urgently required Other diseases Rhizoctonia, black dot, common scab, Sclerotinia Other yield limiting factors