Seed dressing and in-furrow fungicides for canola in Western Australia

Page last updated: Friday, 12 October 2018 - 11:32am

Seed dressing and in-furrow fungicides contain active ingredients for the control or suppression of seed-borne diseases and some fungal root rots in canola. Information on fungicide active ingredients that are registered for different canola diseases in Western Australia is provided here, including blackleg, hypocotyl rot, damping off and root rot.

Introduction

At seeding, fungicides can be applied to seed (seed dressing) or applied in soil (coated on compound fertiliser or mixed with liquid fertiliser or water and applied in-furrow) to be taken up by canola seedlings. Seed dressing fungicides and/or in-furrow products can provide protection from seed-borne diseases and/or suppress early foliar diseases such as blackleg.

Seed dressing and in-furrow fungicides contain one or more active ingredients and are marketed under many different trade names. When choosing seed dressing or in-furrow fungicides, consider the range of diseases that threaten your crop. Consult product labels for registrations, the Australian Pesticides and Veterinary Medicines Authority's Public Chemical Registration Information System Search or InfoPest, or see a list of currently registered active ingredients under 'Documents' on the right. Reassess your disease risk before seeding by looking at seasonal forecasts and crop disease forecasts for your local area specifically the Canola blackleg spore maturity forecast for Western Australia, all available through the Department of Primary Industries and Regional Development (DPIRD).

Blackleg

Early blackleg seedling infections – especially up to the 4-5 leaf stage – are the most damaging in terms of development of severe stem cankers and yield loss. Fungicide seed dressings and in-furrow products can provide protection to canola seedlings from blackleg. You can download the list of registrated products under 'Documents' on the right.

Symptoms of blackleg are described in Diagnosing blackleg in canola. Information on integrated management of this disease is available from GRDC's Blackleg management guide.

For achieving an economic return in terms of fungicide application, apply fungicides in-furrow or on seed when growing a variety with moderate canker resistance or lower and it is under moderate to high disease pressure. Avoid applying fungicides at seeding where a variety has either high resistance (R-MR) together with good yield potential and low disease pressure, or low canker resistance (MS-S) together with very high disease pressure. Fungicides at seeding are not required for varieties with very high canker resistance (R). You can check variety blackleg resistance ratings in the current Canola variety guide for Western Australia.

Protection from upper canopy infection of blackleg later in the seaseon requires application of foliar fungicides, which are listed on the Registered foliar fungicides for canola in Western Australia page.

Damping off, hypocotyl rot and root rot

Damping-off in canola is caused by a complex of rhizoctonia, fusarium and pythium species. Symptoms are described in Diagnosing damping off in canola.

Rhizoctonia affects a wide range of crops, including canola, and has become more prevalent as retaining stubble provides a habitat for the fungus during summer.

Damping off and hypocotyl rot of oilseeds and legumes are all caused by differing strains of rhizoctonia solani. Affected seedlings either fail to emerge, or collapse at ground level in patches. Pictures of symptoms are available in Diagnosing rhizoctonia hypocotyl rot in grain legumes. These diseases occur when conditions are unfavourable for germination and early seedling growth. But yield loss is unusual unless plant numbers are severely reduced or there is patchy establishment. Dry sown crops are more at risk, but if crops are re-sown, soil tillage will generally control the fungi.

Some fungicide seed dressings can reduce damage from these diseases, download the list of registrated products under 'Documents' on the right.

Disease diagnosis

Contact DPIRD's Diagnostic Laboratory Services (DDLS) for assistance with disease identification in seed and plants. Telephone +61 (0)8 9368 3351 or refer to the DDLS - Plant pathology services page.

Economic considerations and decision support tools for blackleg management

The department's Blackleg sporacle model can provide growers with an early warning to avoid the ascospore showers at the critical stage of susceptibility by manipulating the time of sowing the crops if possible. A forecast on the likelihood of first spore showers is available to growers via the Crop diseases: forecasts and management page which is updated regularly at fortnightly intervals from the commencement of every season. The blackleg sporacle model predicts the onset of blackleg ascospore release from canola stubble for 26 canola growing districts of WA using the latest weather data from the nearest weather stations to these locations. Growers are recommended to check the forecasts prior to sowing.

BlacklegCM is a decision support tool developed by DPIRD and available for use on ipad and android tablets that assists with managing blackleg disease in canola crops in Australia. The app has been developed to provide growers and advisers with an interactive interface to explore the economic outcomes of different blackleg management strategies and their relative importance. BlacklegCM allows users to compare the likely profitability of different disease management strategies including paddock selection, variety choice, seed dressing, banded fungicide and foliar fungicide. BlacklegCM takes account of costs, yield benefits, grain price and seasonal conditions to give a best case, worst case and most likely estimates of financial return. The app harnesses 30 years worth of data and information compiled in the Blackleg Management Guide to help identify the most profitable management strategy for individual scenarios. The University of Melbourne, NSW Department of Primary Industries, CSIRO, the South Australian Research and Development Institute, and Victorian consultants Marcroft Grains Pathology also contributed to the development of the app. BlacklegCM does not account for all factors that can affect blackleg disease, so information provided by this tool should not be considered to be tailored to the circumstances of any individual farm. You can download the app from the BlacklegCM page.

Growers should assess their own situation with their adviser to decide whether they should consider the use of fungicides at seeding or not. The point at which it becomes economic to apply them depends on the cost of application and potential yield loss prevented by its application. Their effectiveness is largely dependent on the amount of disease pressure and the level of varietal resistance.

To look at the gross margins with or without using Impact® or Jockey® under various disease pressures in a region with relevant varieties use the BlacklegCM decision support tool which is available for free download on the app and google play stores.

Cautions about using fungicides in furrow and in seed dressings

It is crucial to read and follow directions on fungicide labels carefully to ensure correct and even rate application and safety for seed and farm staff.

For in-furrow treatment, growers should apply them as close as possible to the seed for maximum effectiveness. Canola roots must grow through the fungicide treated fertiliser to achieve an effective uptake of the fungicide. Uneven application and poor placement of the fertiliser could seriously reduce the fungicide effectiveness. In-furrow treatments should not be applied directly to the seed as it is toxic.

Registered seed dressing and in-furrow fungicides for WA canola crops

A table of registered seed dressing and in-furrow fungicides is available to download from this page under 'Document's' on the right. This is a guide only and product labels should be read carefully before application and directions followed. To help keep this table updated, contact Ciara Beard with any new registration information.

Disclaimer

Mention of trade names does not imply endorsement or preference of any company’s product by DPIRD and any omission of a trade name is unintentional. Recommendations are current at the time this page was prepared.

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