Winter cereal growers in Ireland have a significant septoria challenge to overcome as they prepare for T2 flag leaf spray applications.
A mild winter was followed by heavy rain in March and April, with conditions warming in May – the perfect breeding ground for fungal disease to develop.
Crop specialists at Teagasc say septoria levels are heightened but a well-timed fungicide application with curative and preventative chemistry is likely to protect crops well.
Corteva Agriscience is advising growers to use the latest fungicide chemistry, and to assess disease pressure and variety when selecting their application rate in the coming days and weeks.
Shay Phelan, Tillage Specialist at Teagasc, said: “We are seeing quite a bit of septoria in wheat crops – higher than normal. Southern Ireland is probably where the pressure is greatest, but levels are above average in the middle of the country too.
“But the good news is that crops are growing well and flag leaves are fully emerged in many cases, so a period of fine weather now will give farmers the chance to get the situation under control with their T2 sprays.”
Some T0 applications were abandoned altogether, while T1 sprays only took place where weather windows presented themselves.
Liz Glynn, National Technical Manager for Ireland, said this is being reflected in disease pressure which is building in line with May’s climbing temperatures.
“There is plenty of septoria in the base of the crops in the trials we have been looking at and the warm, wet weather will contribute to infection further up the plant,” she said.
“Varietal differences are evident too; Bennington and Graham are two wheats we have seen higher levels of disease in so far this year.”
Shay said he expects growers to alternate their chemistry and use a multisite in their T2 tank mix to protect crops for longer and strengthen anti-resistance strategies.
Liz agrees and is advising growers to use Inatreq, which has proven its ability to deliver curative and preventative persistence against yield-robbing diseases, perhaps most notably in 2021 when a wet spring created similar circumstances to 2023.
Predominantly used at the T2 fungicide timing – growth stage 39 – to elicit the greatest possible yield response, Inatreq helps contain latent disease and protect the crop for the following four-to-six weeks.
The application rate will depend on variety and disease pressure, with rates ranging from 1.5l/ha to 2.0l/ha.
Corteva advises that a robust rate should be targeted where disease pressure is already high, the T1 to T2 gap may have become extended, and where greater persistence of control is required because of ongoing rainfall causing frequent infection events.
Corteva has urged growers to follow its best practice application advice when applying products containing Inatreq active.