Latest oilseed rape fungicide performance reports online

AHDB has published the latest annual fungicide performance reports for light leaf spot and phoma stem canker.

Knowledge of the potential power of a fungicide active ingredient (or product) is essential in disease management. First and foremost, it will help you gauge the potential return on your spray investments. Critically, it can be used to develop effective fungicide programmes that balance the need to control disease with the need to protect chemistry from fungicide resistance.

Fungicide performance information has been generated in this trial series for many years. The oilseed rape series started in 2006. The wheat and barley series go back further (1994 and 2002, respectively).

• We locate trials in areas likely to produce high pressure for the target disease
• We use varieties that are highly susceptible to the target disease
• In the oilseed rape trials, products are applied as two-spray programmes
• Trials provide information on the relative efficacy of active ingredients (disease control and yield response) against the target diseases at a range of doses
• Results can be used build fungicide programmes
• The project also tests chemistry that may receive authorisation for use in oilseed rape
• The long-term trial series is used to monitor the performance of products, which can help detect changes in efficacy (due to fungicide resistance)

Each year, headline results are presented at the Agronomists’ Conference.

Earlier this week, the annual fungicide performance summary reports for these major oilseed rape diseases were published. The reports provide further detail on the trials, results and the implications to disease management.

Phoma stem canker

• There are effective azole and non-azole options for phoma stem canker control, with newer products bringing advantages to disease control and yield (typically, older chemistry performed worst)
• Yield responses ranged from 0.4 to 1.0 t/ha in 2022, with little benefit from applying above half of the full label rate (as part of a two-spray programme)
• Over-years results show that the responses in canker control and yields were more evident under high disease pressure (as expected)

Light leaf spot

• There was relatively low disease pressure in the 2022 trials
• The longer-term dataset provides the best indication of product performance
• Azoles and non-azoles are effective, providing similar disease control and yield benefits
• Yield responses to fungicide application (untreated control, 3.50 t/ha) ranged from 0.3 to 0.6 t/ha (generally, newer chemistry performed best)
• Often, there was little benefit from using above half of the full label rate (as part of a two-spray programme)
• However, optimum dose and yield response is site- and situation-specific, with the required dose dependant on variety resistance rating, crop growth and disease pressure

*Headlines are based on the Agronomists’ Conference 2022 fungicide performance in oilseed rape presentation.

Fungal pathogens of oilseed rape are showing reduced sensitivity to some fungicides and there is concern about declines in efficacy.

With azoles and non-azoles available, it is important to use a range of modes of action, in alternation or as mixtures/co-formulations, throughout the fungicide programme.

For the latest resistance management guidelines, visit the Fungicide Resistance Action Group (FRAG) page.

Where a fungicide is deemed necessary, spray timing is critical to optimise control. AHDB guidance provides information to help you optimise sprays.

*Products do not have a label recommendation for light leaf spot control but may be applied at the appropriate time to control other diseases.

**Products registered in 2021.