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Latest on Pulse diseases – 2019 GRDC Update papers

Chickpea ascochyta

Keep up with the latest research information on pulse diseases including Phytoplasma, Phytophthora root rot and Ascochyta blight. The following papers were presented at the GRDC Updates across Australia in February and March 2019 and August 2018. The papers are sorted by region. Click the paper titles to view the full papers.

Northern
Southern
Western

We’ve also pulled together all the:

Canola disease papers
Cereal disease papers

Phytoplasma In Grain Legumes: What We Know / Don’t Know

Authors: Murray Sharman (Queensland Department of Agriculture and Fisheries), Hugh Brier (Queensland Department of Agriculture and Fisheries), Fiona Filardo (Queensland Department of Agriculture and Fisheries), Peter Vukovic (Queensland Department of Agriculture and Fisheries), Lisa Kelly (Queensland Department of Agriculture and Fisheries), Liz Williams (Queensland Department of Agriculture and Fisheries), Graeme Wright (Peanut Company of Australia)

  • Phytoplasma has caused significant losses in grain legume crops, is widespread in the northern region and infects a wide range of hosts
  • Many things remain unknown. A leafhopper vector is suspected but not confirmed
  • Monitor surrounding weeds for phytoplasma symptoms and maintain good farm hygiene to reduce risk of spread into crops
  • Growers should monitor crops for leafhopper activity and phytoplasma infection and report any outbreaks to Qld DAF entomologists and/or pathologists.

Latest Research On Chickpea Phytophthora Root Rot –Reduced Yield Losses In Crosses With Wild Cicer Relatives

Authors: Sean Bithell (NSW DPI Tamworth), Kristy Hobson (NSW DPI Tamworth), Willy Martin (DAFQ Warwick), Merrill Ryan (DAFQ Warwick), Steve Harden (NSW DPI Tamworth), and Kevin Moore (NSW DPI Tamworth)

  • Avoid paddocks prone to waterlogging, with poorly drained areas, or a history of lucerne, medics or chickpea Phytophthora root rot (PRR)
  • Use the most PRR resistant varieties (rated MR) where there is a risk of PRR
  • Be aware that although more chickpea varieties now have improved resistance to PRR substantial yield losses (40-68%) can still occur, even in a relatively dry season if one soil saturation rainfall event occurs
  • Crosses between chickpea and wild Cicer species, such as the breeding lines CICA1328, CICA1718 and CICA1812, offer improved levels of resistance to PRR.

Chickpea Ascochyta Research: What If I Miss A Spray – Are There Salvage Options With New Chemistry; How Long Do Fungicides Persist?

Authors: Kevin Moore, Steve Harden, Kristy Hobson and Sean Bithell (NSW DPI)

  • Follow latest advice for managing Ascochyta – applying fungicides before rain is a key component of this advice
  • Chlorothalonil and mancozeb fungicides are persistent and rain fast (up to 50mm rain in 10 minutes)
  • If you miss an Ascochyta fungicide spray, research indicates salvage sprays with new chemistry may be an option within tight timeframes, but this requires field confirmation.
  • Do not rely on salvage fungicide sprays as part of your 2019 Ascochyta management plan – aim to spray crops prior to rainfall events.

Pulses 2018 — An Update For Southern NSW

Authors: Mark Richards (NSW DPI, Wagga Wagga Agricultural Institute, Wagga Wagga)

  • Three new pulse varieties were released by the Pulse Breeding Australia (PBA) programs
  • Poor seasonal conditions throughout the 2018 growing season in southern NSW limited yield potential.
  • Disease incidence and severity were low during 2018.
  • Where sub-surface acidity is detected, incorporate lime to a depth of 10cm, at least 12 months before sowing pulses (18 months in drier environments).
  • Biosecurity alert – keep lupin anthracnose out of NSW.

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Southern Region Pulse Performance And Agronomy Update 2018 — Victoria

Authors: Jason Brand and Josh Fanning (Agriculture Victoria)

  • After several seasons of growth, the area sown to pulses in Victoria stabilised in 2018 in response to challenging climatic conditions and lower yields in 2017. Unfortunately, 2018 again proved to be challenging in many regions, particularly the Mallee and Wimmera, with extremely dry conditions and very low yields. High prices with faba beans have benefited many growers in the higher rainfall zone (HRZ) and west and south Wimmera. Many areas of the industry have now matured to a point where growers and advisers see pulses as part of the overall system for enduring on-farm profitability.
  • Varieties: Three new pulse varieties were released in 2018 for production in 2019 — the first faba bean (PBA Bendoc) and a new lentil (PBA Hallmark XT) with high levels of tolerance to some imidazolinone (Group B) herbicides when applied post-emergence, and a faba bean (PBA Marne) with adaptation to the lower rainfall and short season areas.
  • Pathology
    • If seed was retained from paddocks infected with field pea bacterial blight or chickpea ascochyta during 2018, seed testing is recommended to reduce carryover of disease inoculum into 2019.
    • A disease management plan will be required to control pulse diseases during 2019.
    • In inoculated plots, Turnip yellows virus reduced grain yield by approx. 40% in field peas and 25% in lentils. More research is being conducted to validate these results.
  • Sowing time: In contrast to previous sowing date trials which showed reduced grain yield from delayed sowing, in 2018 significant increases in grain yield in lentils and chickpeas at Ouyen from delayed sowing were observed. This was primarily due to the extremely frosty conditions during the reproductive phase. Economically, lentils would have made a loss at the yields achieved in the trials in 2018. Growing chickpeas would have been highly profitable (estimated returns of $200-$500/ha) at most sowing dates. primarily due to the extremely frosty conditions during the reproductive phase. Economically, lentils would have made a loss at the yields achieved in the trials in 2018. Growing chickpeas would have been highly profitable (estimated returns of $200-$500/ha) at most sowing dates.
  • Novel herbicide tolerance: A breeding line with improved Group C herbicide tolerance demonstrated tolerance to a range of Group C products and has the potential to further enhance the yield stability in lentils across a range of soil types and improve weed control options.

Emerging Pulse Root Diseases In The South East Region Of South Australia

Authors: Tara Garrard, Kelly Hill, Katherine Linsell, Alan McKay (South Australian Research and Development Institute)

  • Pulse crops can suffer from root diseases.
  • Next generation sequencing (NGS) technology has potentially identified multiple pathogens of economic significance on South Australian (SA) crops — further work needs to determine which are the most important.
  • Intensification of pulses in cropping rotations can increase pulse soilborne diseases.
  • If you suspect soilborne disease issues in your pulse crops, send samples to SARDI.

Ascochyta Blight In Intensive Cropping Of Pulses

Authors: Sara Blake, Liz Farquharson, Rohan Kimber, Jenny Davidson and Christine Walela (SARDI), Kristy Hobson (NSW DPI)

  • PBA Hurricane XT is now rated moderately resistant – moderately susceptible (MRMS) for foliar ascochyta blight in South Australia (SA) due to shifts in the pathogen population, most likely in response to intensive cropping of this cultivar.
  • The newly released cultivar PBA Hallmark XT is also rated MRMS to ascochyta blight and as this cultivar has the same source of resistance as PBA Hurricane XT growers must be vigilant in monitoring for signs of disease.
  • The lentil cultivar Nipper was infected by a lower percentage of recently collected isolates in controlled environment studies compared to previous years suggesting that cultivar rotation can manipulate the pathogen population.
  • Faba bean cultivars have not changed their resistance status to ascochyta blight since 2015. Screening of recent isolates of Ascochyta fabae confirmed that Farah remains susceptible to all strains of ascochyta blight, PBA Rana and PBA Zahra are rated, while PBA Samira and Nura remain resistant.
  • Previous reports of higher than expected levels of ascochyta blight in commercial crops of PBA Samira faba beans are likely due to outcrossed seed being kept from the previous year for planting. Tests using A. fabae isolates on pure PBA Samira seed showed a resistant response to current ascochyta blight pathogen strains.
  • Chickpea cultivars in the southern region are now all moderately susceptible or susceptible to ascochyta blight, requiring a thiram-based seed dressing and multiple foliar fungicide applications.
  • Growers are encouraged to review their integrated disease management (IDM) strategies including cultivar selections for pulses in their farming system. To help protect the industry from loss of disease resistance, implement a 3-4 year break between crops of the same type, revise cultivar selections and avoid sowing in paddock(s) in close proximity to previous years’ crops. Growers should monitor crops for signs of disease and ensure fungicide applications are applied ahead of rain fronts.

Disease Management Of Pulses Grown In Low To Medium Rainfall Zones

Authors: Jenny Davidson (SARDI) and Sarah Noack (Hart Field site Group)

  • Fungal pathogens and viruses survive between crops on infected stubble, seed and or directly in the soil. General crop management to minimise disease risk includes:
    • Crop rotations of three years between the same crop type.
    • Avoid planting in paddocks next to stubble of the same crop type.
    • Volunteer plants which may be infected should be removed before the new crop is planted.
    • Fungicide seed dressings are an important strategy to minimise transfer of disease from seed to seedling.
    • Test seed for virus infection and replace infected seed.
    • Use foliar fungicides where appropriate and economic to do so.

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New Fungicides For Controlling Ascochyta In Chickpea

Authors: Martin Harries, Mark Seymour, Stephanie Boyce (DPIRD).

  • One or two well timed fungicide applications increased yield 10% and full control a further 15%.
  • Newer fungicides were more effective at suppressing ascochyta but this did not translate to increased yield.
  • Further testing of new fungicides is required in more locations and seasons.

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