A new fungicide will help bulb onion growers improve disease control and crop quality.
Unicur, from Bayer CropScience, is a co-formulation of the strobilurin fungicide fluoxastrobin and the triazolinthione prothioconazole.
According to Allium and Brassica Centre consultant Andy Richardson it as an “eagerly awaited and very exciting introduction for onion growers”.
Richardson said: “It has clearly been one of the best in our trials over the last five years and is currently the only product that controls all three diseases; downy mildew - the potentially most devastating - Botrytis leaf spot and Cladosporium. Its arrival this month also broadens the range of fungicides with different modes of action available to us, so it’s great news for resistance management too.”
The product label allows use in programmes at any stage from when the leaf bases begin to thicken at bulb initiation until ten per cent foliage fallover. Richardson expects growers will want to make full use of it from the five to six true leaf stage and advises alternation with mancozeb-based treatments to stay within resistance management guidelines.
He added: “Downy mildew control is critical to produce the bright, thick-skinned onions retailers want. Late infection - from nine to ten leaves onwards - produces bulbs with thin skins that can crack or get rubbed off when grading out of store. The result is ’skinned’ onions that maybe downgraded from pre-pack to wholesale or even processing. Being able to use Unicur up to the end of programmes will be a big help against this."
Maximum individual dose is 1.25l per hectare and the maximum total dose per crop permitted by the product label is 5 L/ha. However, Dr Meredith points out that as Unicur contains fluoxastrobin, a member of the QoI fungicide group, FRAC guidelines must be followed.
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