Download articleLucy de la Pasture

Daffodils in December, blackthorn flowering in January and in February, blackgrass plants in untreated stubbles have been reported to be in ear. The birds have already changed their song thinking spring is just around the corner. It’s a very British topic of conversation, but what’s going on with the weather? No wonder everything’s confused!

According to the experts at the Met Office, a very strong El Niño effect is part of the reason and if we then get something called sudden stratospheric warming, then there may yet still be a late cold spell. It certainly has all the makings of being an interesting season and not just because of the weather.

The lively debate about whether or not to use an azole at T0 is a fascinating one. It’s hard to fault the logic of the Irish – using an azole early may compromise its effectiveness on septoria at later timings. If we’re relying on azoles to help protect our trump card, the SDHIs, well I can see where they’re coming from.

But is it an over-simplistic view? Possibly, or certainly when crops are under pressure from yellow and/or brown rust which can be every bit as devastating as septoria in a bad season. There has to be a compromise and you have to do what’s best for the crop you have in the ground.

Some may say that it just creates confusion when the experts don’t agree but in my view, no one really knows for certain what the answer is when it comes to resistance. What we do know is that eventually losing some of the activity of our best fungicides is inevitable. What we don’t know is precisely how much efficacy will be affected and how quickly this will happen.

In spite of the fact that resistance is unavoidable in the long run, we do need to consider resistance at every turn. Every bit of research published adds to the pool of knowledge and sometimes incites a vigorous exchange of views. That leads to more research, more interpretation and eventually stronger advice.

It’s healthy to have differing opinions and it’s useful to hear what they are, because it’s important to have the information to consider. In practice there’s always a compromise to be made between controlling a range of diseases and managing resistance. Whichever argument you may subscribe to, it seems the best thing you can do is use a multisite whenever you reach for a can of azole. At least everyone agrees on that.

Another message that keeps being repeated is that we really ‘could do better’ when it comes to getting fungicide timings right. Improving application timing is probably the one thing that we can all attempt to do that will really help take some of the pressure off our fungicides. I was a bit horrified to learn from Bill Clark that T1 is a term we all use but not everyone knows what the correct timing actually is! For the record, it’s when leaf three is almost fully emerged on the main stem – tillers will be a little behind.

It’s a bit fiddly but there’s something very rewarding about dissecting a stem and seeing the ear already sitting there at the base. If getting the knife out and cutting stems open means getting the fungicide on the correct leaf and making sure the ear has every chance of reaching its potential, then it’s worth spending a bit of time getting the timing bang on.

The Bayer time lapse work very clearly shows the importance of green leaf retention in relation to yield, and it’s worth noting that the fungicide applications on the trial sites were carefully timed to perfection. Another indicator that if you want the best value out of fungicides, which aren’t cheap, pay close attention to application.

It’s probably worth getting a feel for which varieties are earlier and checking development before the sprayer gets in the field. The difficulty for agronomists is getting round their patch to truly nail every timing, so many are having to produce T1 recommendations before the event. Those growers who can accurately assess their growth stage will help their agronomist out and have more chance of getting the spray timing spot on. They’ll also help the industry in keeping levels of inoculum, and application rates needed to control it, to a minimum.

Based in Ludlow, Shrops, Lucy de la Pasture has worked as an agronomist and wonders whether this year, March might be the right timing for a barbecue.