Next Tuesday, May 19, is the last day that Irish tillage farmers may use chlorothalonil.

The product’s use is banned from May 20, 2020. Any product on farms should be used by this date.

Crops being sprayed before this date may receive chlorothalonil. Final sprays on winter barley and T2s on winter wheat will require chlorothalonil.

Therefore, winter barley and winter wheat programmes receiving final sprays and T2s before May 20 will be unchanged for this season provided farmers have chlorothalonil in stock.

As chlorothalonil offers prevention of ramularia, some farmers may consider applying chlorothalonil in T1 fungicides on spring barley in an effort to control the disease for the 2020 season.

Broad spectrum

Chlorothalonil is a broad-spectrum fungicide and is also used in spray programmes as part of an anti-resistance strategy.

Farmers spraying products after this date should consider using other broad-spectrum fungicides such as Folpet.

Further down the line and a new product Adepidyn (a broad-spectrum fungicide), also from Syngenta, looks to be showing promise as a possible replacement for chlorothalonil but this product is still in trial and has not been registered.

Chlorothalonil ban

Member states endorsed the EU Commission’s proposal to ban chlorothalonil in March 2019. Countries like Ireland, the UK and Belgium were thought to be the countries which depended on the product in disease programmes most due to high pressure disease environments.

Derogations were suggested for some countries, but Ireland did not receive a derogation.