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Spring barley yields are likely to suffer yield losses of 10% if chlorothalonil (CTL) is withdrawn from the market.
The active has come under pressure within Europe in relation to concerns around its alleged carcinogenicity (capacity to produce cancer) and a suggested risk to ground water.
The active could be facing total withdrawal from the market or restrictions around timings and rates.
When floplet is added into the fungicide programme, losses of 6% are likely, but 10% is possible
Steven Kildea of Teagasc presented results from trial work carried out in 2016 and 2017 which showed yield losses of between 4.3-15% in spring barley due to the absence of CTL in the fungicide programme.
Losses would most likely be closer to 10%, he said.
When floplet is added into the fungicide programme, losses of 6% are likely, but 10% is possible, see Table 1.
Ramularia – a global disease
Prof Fiona Burnett of the SRUC discussed the prevalence of ramularia in Scottish barley crops.
Barley is the largest crop in Scotland and second in the UK and contributes significantly to the farming economy.
Ramularia is a significant problem in the southern hemisphere. Epidemics have been reported in New Zealand, Uruguay, Argentina and recently Tasmania
Fiona stated that while the disease is more common in spring barley crops, it can also be just as damaging to winter barley crops.
Ramularia is not a new disease and travels with the seed.
The disease is very closely related to septoria in terms of genetic make-up and one of its key strengths is its ability to over-winter on straw.
Ramularia is a significant problem in the southern hemisphere.
Epidemics have been reported in New Zealand, Uruguay, Argentina and recently Tasmania.
In New Zealand, there is extensive succinate dehydrogenase inhibitors (SDHIs) mutations but demethylation inhibitors (DMIs) are still effective.
There is a mixed picture across Europe. UK and German activity from SDHI and DMI chemistry is compromised.
In Ireland and Denmark, there is still some activity from SDHI and DMIs. Interestingly there is no CTL in Denmark.
In South America they are still using SDHI, QoI and triazole mix with control appearing to hold.
2018 report
Last year, Teagasc published a report into the impact on yield and net margins in barley and wheat as a result of the loss of CTL.
The report indicated that yield loss in barley, in the absence of CTL, is likely to be between 5-11% and with production cost per tonne of spring barley (without CTL) increasing by between 5-11%. However, it also estimates that net margins could be decreased by a substantial 65% in the absence of CTL.
The annual industry conference is in its 10th year and is being held in the the Lyrath Hotel, Co Kilkenny today.
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