Septoria and gout fly are the main crop protection challenges facing winter wheat crops at Bayer CropScience’s development site in Callow, Herefordshire, as the spring season gets under way.
With the 30 varieties in trials on the site near Hereford at or approaching GS30, the plan currently is to apply the T0 fungicide during the last week of March, says the company’s commercial technical manager Gareth Bubb.
Varietal differences in development are starting to become apparent, although after a cold, very wet spell and recent frosts, the plots are not as far forward as might be expected, he adds.
“There is plenty of septoria and quite a lot of mildew, but no yellow rust,” Mr Bubb says.
At present the scene is set for a high disease pressure season, although as ever the weather will be a major influence. Mr Bubb advises it is not currently looking like a season in which to cut costs.
“I think we are currently in for a really high disease season, higher than last year. There has been a lot of talk about yellow rust but that is site specific, while septoria is consistent across the country,” he says.
A visit to the site in the second week of March revealed plenty of dead leaf tissue and a lot of active septoria tritici inoculum.
“How that develops will depend on temperature and rainfall,” says Mr Bubb.
The recent cold snap will have slowed disease development down to some extent but is unlikely to have stopped it completely, he adds.
“It will have had more of an effect on the rust than the mildew and will slow the septoria down but it won’t have had a big effect; it won’t stop the disease,” Mr Bubb says. “The new leaves have probably already got septoria infections. There are a lot of active septoria picnidia visible.”
The T0 at Callow is likely to be a straight Bravo (chlorothalonil) – it is not a rust-susceptible site, adds Mr Bubb.
“The most important thing about the T0 is the interval between it and T1; it can’t be more than three weeks,” he says. “The T1 timing is important, if you miss leaf three you could find yourself in a bad situation.”
Bayer will be installing the time lapse cameras at the Callow site in early April. These will take close-up images of the winter wheat crop every 20 minutes, and these will be available at www.bayercropscience.co.uk.
For a review of the time lapse project findings since 2014 go www.fginsight.com/arable.
Mr Bubb advises growers to start dissecting plants from the first week of April to keep a close eye on crop development stages and enable T1 sprays to be timed carefully.
Early-sown (September 11) winter wheat plots at the Callow site were showing very high levels of gout fly infestation.
Bayer technical manager Gareth Bubb says: “It’s the worse gout fly damage I’ve ever seen. There is a massive difference between plots sown at the beginning of and in the middle of September.”
According to ADAS, reports of gout fly infestations are also being received from Essex, Lincolnshire, Herefordshire, the West, Oxfordshire and North Yorkshire. Some agronomists are said to are reporting very high levels.
Growers are advised there is nothing that can be done now against the pest.
“Gout fly only attacks a single tiller so any application of insecticides now would only be revenge,” says ADAS.