Cold snap checks OSR crops
9 Apr 2021
This month we are checking in with the OSR diarists to find out how crops are getting on the Scottish borders and southern England. Our agronomy manager, Matthew Barnes, sheds light on crops further north.
Tom Hoggan - Grower from Berwickshire
“Last week was warm with bright sunshine and maximum daytime temperatures ranging from 12 to 15C. Now we’re getting frosts at night and the wind is bitter. Temperatures dropped heading into the easter weekend so our OSR, which probably would have been flowering this week, has keeled over and is looking a little sorry for itself.
“On the plus side the pigeons have gone; the canopy has closed across most of the acreage so there’s nowhere for them to land.
“Our crops have had both doses of nitrogen via N sensor as well as a light leaf spot fungicide (prothioconazole) which was applied beginning of March. We just need a little warmer weather – which thankfully is in the longer range forecast - and it’ll get moving, I’m sure.
“When it does get going, we’ll be applying tebuconazole to top up protection against light leaf spot. It also doubles up as a plant growth regulator. Having been fairly dry, we’ve relatively low disease pressure and while crops are looking good, they aren’t too forward. This weather will slow growth too, so the tebuconazole should be enough to check growth and even the crop.
"After that, we will be keeping a close eye on the weather to see if a sclerotia spray is warranted.”
Adrian Joynt - Grower from Shropshire
Mathew Barnes – Agronomy Manager based in Yorkshire
“Oilseed rape is the best it has looked for many years in the North of England. Overall, it’s established well with very few patches and some large canopies going into the winter, something we’ve not seen in quite a while.
“Some later drilled crops that didn’t establish as well have suffered with the cold and wet winter and look a little patchy. Even though pressure from CSFB was very low in August and early September this doesn’t always correlate with the spring larvae population, so monitoring is key. Plants harbouring heavy CSFB larval populations are becoming evident as the unaffected crop grows away leaving these stunted plants behind. That unevenness will make managing the crop a bit more difficult, but at least the crop is there!
“Some of my growers have already used Caryx® in the autumn and are coming back with it again this spring, especially in those early drilled crops where canopies will need to be managed and lodging risk reduced. The primary benefit of Caryx® is that reliable PGR effect but as we enter a drier period now this will also help with increased rooting, resulting in better up take of what moisture is around lower in the profile.”
Tim Hayward - Grower from Berkshire
“There’s no doubt this weather has certainly put the brakes on! There are always silver linings though; disease pressure is down and having had this sort of weather before, we know, the crop will be ok.
“Our OSR didn’t need holding back, so the last of the nitrogen applications, urea, went on 10 days ago – just ahead of the last rain.
“Some of the acreage has been held back by CSFB damage and the weather. Those fields are just waiting for some warmer conditions. Elsewhere we’ve a few yellow buds but most plants are at flower stalk extension. There’s been a tiny bit of light leaf spot but nothing to write home about. No doubt we’ll have some worries to come, but for now most of the crop is looking well.”
Mike Wilton - Grower from Norfolk
“We’ve gone from 15/16C to 6C and the crop is growing very slowly. It’s been at green bud for about a week and it needs some sunshine.
“To all intents and purposes, all the nitrogen applications have been done. The only thing left is a foliar treatment towards the end of flowering.
“Interestingly, laboratory testing is showing more light leaf spot than we would like. I’ll see what happens in the next week to ten days and may go back in with a fungicide just to knock that on the head.
“We will continue to monitor the crop with fortnightly tissue analysis. Presently, the only nutrient the crop looks low in is magnesium. We’ve learnt from previous years that if we’re seeing low levels when the crop is growing slowly, when growth picks up the situation is quickly exacerbated.
“Usually at this time of year we’d be looking at a plant growth regulator but the weather is doing that job for me. So generally, other than fungicides and a little late N, we’re done!”