Stubble Disease Management Table

Disease Rhizoctonia Crown Rot
Symptoms Shortened, brown, spear tipped roots. Bare or stunted patches in the paddock, from just a few plants to metres across.

 

Often, by the time you can see the symptoms there is no practice that can cure the disease. Later in the season, white head or ‘dead heads’ will appear uniformly across the paddock at flowering or early grain fill.

Disease appearance

When to monitor Before sowing and 2-3 leaf stage.

Cereal growth stages

 

Predicta B pre-sow. Look for whiteheads at early grain fill and stem browning from late grain fill to harvest. The disease blocks the transfer or nutrients and moisture to the filling head. The heads that are mainly affected are tillers. These heads will contain either no grain or severely shrivelled. Browning or honey comb discolouration of stem bases of affected plants is also seen as well a pink discoloration behind the leaf sheath
Crops affected and

host plant

Predominantly cereals but it also causes losses in pulses and pastures. Crown rot is hosted by ALL winter cereals and many grassy weeds.

Durum wheat is most affected, followed by wheat and then barley. Barley being an earlier maturing crop tends to escape the significant yield loss.

Management There are no known cultivars that are resistant to the disease. Different crop types such as canola, can reduce inoculum levels in low rainfall, light textured soils. The best management of crown rot is through rotations and break down of the stubble. Any crop rotation used as a break crop must be grass free otherwise the disease levels will remain or increase overtime. The inoculum levels can survive several years and only reduce as stubble decomposes. Practices such as slashing, cultivation, spreading and grazing can increase stubble breakdown but can also spread inoculum and may increase infection if conditions are poor for stubble breakdown. Burning is not useful as inoculum is below the soil surface.
Recent Research BCG 2012 Stop the root rot article

 

MSF Management of Rhizoctonia

 

Rhizoctonia factsheet

GRDC crown rot factsheet:

 

Agriculture Victoria/BCG 2015 Crown Rot

 

BCG stubble borne diseases

Disease Yellow Leaf Spot (YLS) Spot Form Net Blotch (SFNB)
Symptoms Tan coloured lesions surrounded with yellow halos on leaves and black fruiting bodies on the stubble.

Once infected, the disease can be difficult to control with fungicides.

 

Foliar disease, characterised by dark brown spots or lesions on leaf blades and sheaths often with a yellow surround. Severely affected leaves may die. Stem is weakened and lodging may occur.
When to monitor Mostly occurs in early growth stages in winter. Optimal conditions are temperatures of 15-28oC and up to 12 hours of leaf wetness. YLS can persist for two years in dry conditions. Late tillering to GS30 (before stem elongation).

Other cereals can carry the disease, barley grass in your green bridge? It’s hosting the disease! Monitoring summer fallows can reduce green bridge.

 

Crops affected and

host plant

Wheat Barley and Barley Grass
Management Use resistant varieties and have break crops. The reduction of stubble can reduce inoculum levels but can pose erosion risks. Fungicide provides protection for three weeks. If a susceptible crop has YLS and conditions are likely to be favourable (prolonged leaf wetting and temperatures between 15-28 oC) then fungicide could provide some protection. Apply according to foliar application timings (GS31 and GS39)

 

Azoxystrobin, Epoxiconazole or Propiconazole products.

Apply fungicide during stages GS31-39 if necessary (>10% leaf affected). Monitor and apply a second foliar fungicide if necessary. Seed treatment Systiva® is effective at suppression during tillering, can replace foliar application at GS31, good at suppressing some other foliar diseases (scald, NFNB). In a dry year such as 2015 it may not be economical to apply fungicide. Dry seasons mean a low level of stubble breakdown so more spores present, although sowing early can increase disease pressure as the crop can mature earlier when disease levels are highest, having the greatest impact on crop growth and yield. Plant resistant varieties and rotate crops, apply a foliar fungicide if necessary according to foliar application timings.

Recent Research BCG has done many articles on stubble borne diseases.

A trial conducted in 2011 in conjunction with FAR (Nick Poole) identified which disease control method was best.

GRDC fact sheet:

2016 Winter crop sowing guide, pp. 120 for fungicide options

2016 Winter crop sowing guide pp. 120 for fungicide options

 

2014 AgricultureVictoria/BCG SFNB article

 

2015 SFNB management article

 

2015 BCG barley variety performance

By Jessica Lemon                                                                                         BCG logo with white background      Research Officer (BCG)                                                                                     jessica@bcg.org.au

 

 

 

GRDCLogoStacked_TM_CMYKThis research is being conducted by BCG as part of the GRDC Maintaining profitable farming systems with retained stubble initiative (project BWD00024 Maintaining profitable farming systems with retained stubble in Victoria and Tasmania).

 

Disclaimer: Any recommendations, suggestions or opinions contained in this publication do not necessarily represent the policy or views of Irrigated Cropping Council or the Grains Research and Development Corporation (GRDC). No person should act on the basis of the contents of this publication without first obtaining specific, independent professional advice. BCG and GRDC and contributors to these guidelines may identify products by proprietary or trade names to help readers identify particular types of products. We do not endorse or recommend the products of any manufacturer referred to. Other products may perform as well as or better than those specifically referred to. BCG and GRDC will not be liable for any loss, damage, cost or expense incurred or arising by reason of any person using or relying on the information in this publication.
Stubble project overview: This guideline has been developed for Birchip Cropping Group as part of the Maintaining Profitable Farming Systems with Retained Stubble initiative, funded by the Grains Research and Development Corporation (GRDC). The initiative involves farming systems groups in Victoria, South Australia, southern and central New South Wales and Tasmania collaborating with research organisation’s and agribusiness to explore and address issues for growers that impact the profitability of cropping systems with stubble, including pests, diseases, weeds, nutrition and the physical aspects of sowing and establishing crops in heavy residues.
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About BCG

Birchip Cropping Group Inc. (BCG) is a not-for-profit agricultural research and extension organisation led by farmers in the Victorian Wimmera and Mallee.
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