Early findings in fungicide trials in Fife, which are focusing on minimising the impact of downy mildew in brassicas, indicate that a newly authorised product, Revus, performed better than the current standard, Amistar.
Agronomist James Rose from East of Scotland Growers (ESG), a partner in the trials, said that downy mildew is a growing concern in brassicas because of the way the crops are processed to produce prepared broccoli in florets.
He added: “We wanted to trial a range of fungicides to try to minimise its impact and approached AHDB for support.”
Angela Huckle, from ADAS, who is leading the two-year programme of trials, compared a number of conventional fungicide programmes alongside a biological fungicide to treat the crops. She said: “Downy mildew appears as blemishes on the underside of the broccoli or cauliflower leaves which sporulate, producing a white fluff-like mould which releases new spores, further reinfecting the plant and others around it.
“This can become systemic and once it’s in the broccoli or cauliflower head it creates grey streaking in the stems. When you divide it into florets the streaking makes the brassica unsaleable.”
Ms Huckle pointed out that while disease levels were low in the trial, it became clear that Revus gave the greatest reduction in mildew lesions. However, she said: “I would hasten to add it is good to integrate both modes of action in a fungicide programme to guard against resistance development.”
Herbicide trials using the three most promising products to come out of AHDB’s SCEPTREplus programme, which researches sustainable plant products in horticulture, are also being run in Fife to look at how they respond on broccoli and Brussels sprouts.
The Scottish Strategic Centre for field vegetables complements work being done at a centre in Cornwall, which conducts variety evaluation trials each year and one in Lincolnshire, which conducts grower-led trials. The Fife programme of trials is also looking at the impact of bio-stimulants on crop health and vigour.
Scotland is one of the three key brassica production regions in the UK, with growers supplying broccoli, cauliflower, Brussels sprouts and swedes to supermarkets.