Winter cereal growers in Ireland have been warned that they could face 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 have said that septoria levels are heightened.
But a well-timed fungicide application with curative and preventative chemistry is likely to protect crops well.
Corteva Agriscience has also advise 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.
Septoria
Shay Phelan, tillage specialist at Teagasc, said:
“We are seeing quite a bit of septoria in Irish wheat crops: higher than normal.
“The south of the country is probably where the pressure is greatest. But levels are above average in the midlands as well.”
But he also said 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,” Phelan added
There is evidence that as a direct consequence of the very change bale spring weather, some T0 fungicide applications were abandoned altogether, while T1 sprays only took place where weather windows presented themselves.
Liz Glynn, Corteva’s 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.
“Varietal differences are evident too; Bennington and Graham are two wheats we have seen higher levels of disease in so far this year,” she said.
Shay Phelan expects growers to alternate their chemistry and use a multisite in their T2 tank mix, in order to protect crops for longer and strengthen anti-resistance strategies.
Glynn has also advised growers to use Inatreq, which has proven its ability to deliver curative and preventative persistence against yield-robbing diseases.
The product is predominantly used as a T2 fungicide – growth stage 39 – to elicit the greatest possible yield response.
The application rate will depend on variety and disease pressure, with rates ranging from 1.5l/ha to 2.0l/ha.