Taking care with foliar fungicides
The impact of fungal diseases in cereal crops, such as rust in wheat and barley, is expected to be very high during the 2011 cropping season. The Department of Primary Industries (DPI) is seeking assistance from industry to remind growers to take care when using foliar fungicides and ensure label use restrictions are observed to maintain access to markets.
A common option for rust treatment is the application of foliar products that contain the triazole fungicide, tebuconazole. Tebuconazole breaks down relatively slowly in plants, hence users must observe the product label use restrictions regarding the total amount that can be applied per season to one crop. This will ensure harvested crops don't exceed the tebuconazole maximum residue limit (MRL) in cereal grains.
Tebuconazole is formulated into several product types for foliar application including:
- 430 g/L tebuconazole products (e.g. Bayer Folicur® 430 SC and similar products from several other manufacturers)
- 500 g/L tebuconazole (Nufarm Hornet® 500 SC)
- 210 g/L tebuconazole co-formulated with 210 g/L prothioconazole (Bayer Prosaro® 420 SC).
Whilst this advice is specific to tebuconazole use in wheat and barley crops, the same requirements apply to all chemical products used in any crop. It is essential that users follow the product label directions. Adhering to the maximum label rate, number and frequency of treatments, withholding periods and any prohibitions (i.e. DO NOT statements) or restrictions will ensure that treated grain will meet domestic market requirements. Growers exporting crops need to be aware of, and meet the MRLs of importing countries.
Remember, the most important part of any pest, weed or disease treatment program is planning ahead. Consult your local agronomist or consultant regarding a rust control program that is appropriate for your specific situation.
Tebuconazole spraying programs available for wheat and barley
Only one of the following tebuconazole spraying programs may be applied to a wheat or barley crop per season to ensure that MRL standards are met:
- One application of any product containing 430 g/L tebuconazole at the maximum label rate of 290 mL/ha
- Two applications of any product containing 430 g/L tebuconazole at the lower rate of 145 mL/ha
- One application of Nufarm Hornet® 500 SC at the maximum label rate of 250 mL/ha
- Two applications of Nufarm Hornet® 500 SC at the lower rate of 125 mL/ha
- One application of any product containing 430 g/L tebuconazole at the lower rate of 145 mL/ha and one application of Hornet® 500 SC at the lower rate of 125 mL/ha
- Two applications of Bayer Prosaro® 420 SC at the maximum label rate of 300 mL/ha
- One application of Bayer Prosaro® 420 SC at the maximum label rate of 300 mL/h and one application of any product containing 430 g/L tebuconazole at the lower rate of 145 mL/ha, or
- One application of Bayer Prosaro® 420 SC at the maximum label rate of 300 mL/h and one application of Nufarm Hornet® 500 SC at the lower rate of 125 mL/ha.
Example: You can apply either Bayer Folicur® 430 SC at 290 mL/ha once or apply 250 mL/ha of Nufarm Hornet® 500 SC once, but you can't apply both in the same season.
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