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Downy mildew also cause for concern this year
If you think back to onion cultivation in 2021, you will still be able to remember the unprecedented pressure of downy mildew. In the past year, also during the winter meetings, much attention has been paid to the way in which downy mildew manifests itself and which matters can be important for control.
In particular, shrinkage in the package of resources, resistance management and damage to plots of first-year onion sets provided food for thought.
'You don't have to search long'
It will come as a surprise to few that downy mildew is already showing itself in full in second-year onion sets from latent infected plant material. Although we have rarely seen major infections from systemically diseased plants on this scale and therefore have limited knowledge about them, it is not illogical to draw a comparison with, for example, latent Phtytophthora in potatoes. Growing conditions early in the season determine whether – and for how long – a systemically diseased plant can infect its environment. At the moment, those conditions seem favorable for downy mildew. This is not only a concern for the second-year onion set cultivation, but also for the seed onion plots that are only now in the foliage growth phase and have more than three months of growth to go.
Keeping healthy what's healthy
'Prevention is better than cure' applies in particular to downy mildew control. A strictly preventive approach is necessary. Make sure you are aware of the pressure in the area and act on time based on, for example, a BOS system.
With Fandango you have the broadest-acting product in onion cultivation. An excellent preventive effect on downy mildew, Stemphylium and leaf spot and a good side effect on paper spot and soil-borne diseases. Fandango may be applied a maximum of four times from bulb formation at a dose of 1,25 L/ha with an interval of five to ten days.
To complete the schedule, you can alternate with, for example, Zorvec Endavia¹ where you use 0,5 L/ha Luna Experience can be added to also control leaf spot and Stemphylium.
Use the available fungicides wisely. Respect the legal instructions for use at all times and limit resistance risk by following the FRAC guidelines.
