Keeping OSR Profitable Despite Flea Beetle Threat

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Changing some areas of basic farm management has helped one committed producer to reduce the threat of flea beetle significantly and justify oilseed rape’s ongoing place in the rotation.

Despite farming in a flea beetle hotspot, Oxfordshire grower David Passmore has managed to achieve good establishment and yields in his oilseed rape over the last three years.

Changing his method of seedbed preparation, keeping an eye on soil moisture content and drilling earlier than previously have all helped deliver consistent establishment despite many crops in the area failing.

“We’ve probably been lucky to a degree,” he acknowledges. “But we’ve been prepared to change how we manage the crop and focus more on establishment than chasing the highest yields - and it seems to be working.

“All in all, the average yields approaching 6.0t/ha that we used to get are probably not going to be back for a while, but we’re still confident we can consistently achieve 4.5t/ha, which is not bad for our location.”

The 300ha Mays Farm, Ewelme, sits on predominantly grade 3 loam over chalk and supports a pedigree Limousin beef suckler herd alongside a 200ha arable rotation based mainly on the production of high quality seed.

“It probably means we’re a bit more careful with weed control but apart from that, the crops are grown pretty much the same as commercial ones

“Flea beetle arrived here about four years ago, a bit later than in counties further East, but it’s taken hold and probably half of the crops in the area were lost last year.

“It’s made us realise that if we’re going to continue growing oilseed rape, we have to make some changes – not just with regard to establishment and the critical first few weeks after drilling, but also in the longer-term overall management of the crop.

“Oilseed rape is notoriously front-loaded cost-wise, so the less you have to spend up front, the less the loss if, despite your best efforts, it does fail.”

For David one of the biggest aspects of improving establishment and reducing costs was moving away from a cultivation strategy based on ploughing.

“In past years we would put a load of FYM and other organic material on the land and then plough and press it.

“We’d be careful not to drill too early - usually waiting until around 8th September - and we would get super crops. I’ve seen the combine yield monitor holding at around 7t/ha for KWS Campus in large parts of some fields.

“With Neonicotinoid-dressed seed you could drill quite late into a ploughed seedbed and it wouldn’t really matter if it didn’t rain until the end of September’.

“If you take this approach now, and you get three weeks without moisture, you end up

with a little plant struggling in a fairly rough seedbed and there’s just too much risk involved.

“The combined effects of low moisture and sustained flea beetle attack can be just too much for plants.”

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Last year direct drilling straight into wheat stubble to improve the reliability of establishment was tried for the first time and this seems to have worked well, David says.

“We drilled on 26th August into a fairly moist seedbed - I’m still not comfortable going much earlier than this.

“If you plant oilseed rape earlier, you can get it away before the flea beetle migration starts but you’ll end up with a lot of larvae in it.

“A lot of crops around here that seem OK through the winter often look as if they’ve been sprayed with gramoxone by the time spring arrives - they’ve got that much flea beetle larvae in them.

“There’s a lot of luck around when you catch the rain and the time of the flea beetle migration but on balance, I think mid to late August drilling is the best bet for us now.

“You’ll probably get the flea beetle pressure during establishment but you’ll suffer less with larvae problems later.”

It’s made us realise that if we’re going to continue growing oilseed rape, we have to make some changes
David Passmore, Oxfordshire Grower

Key to getting the crop through the first critical few weeks is choosing the right variety, David Passmore says.

“I’m a big fan of KWS Campus and have been growing it for 5 years now. There are doubtless newer varieties that promise higher yields, but that’s not the most important factor now.

“You want a strong, resilient variety that will establish well and that you can rely on. Campus has proved itself over so many years now and it always keeps upright and yields well in a variety of growing conditions.

“It’s a firm favourite with growers because of this and has won a lot of loyalty on-farm.”

This year Campus’s inherent vigour was helped by an application of DAP (di ammonium phosphate) directly into the drill row, he adds.

“I think you get a much more immediate effect if you place the fertiliser next to the plants rather than simply broadcasting it. Last year’s crop started to grow almost as soon as it was drilled.

“When you have small seedlings struggling with flea beetle pressure, they need all the help they can get, even with a variety with a lot of inbuilt vigour like Campus.”

Seeds are drilled at 50 seeds/m2 – a bit less than most recommendations for conventional oilseed rape, David Passmore points out.

“You don’t need very many plants to make a good crop of oilseed rape and there’s quite a range where it doesn’t really matter what precise seed rate you use.

“If you get it too thick you can get problems with lodging later, but equally if it’s too thin and you lose some to flea beetle, yields will be affected. I think 50 seeds/m2 is a happy medium for here.”

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Direct drilling the seed into the stubble also has other advantages, he adds.

“You don’t need a pre-emergence herbicide doing it this way, so you’re not frontloading so much of your expenditure.

“You can easily pay £40-45/ha on a pre-emergence herbicide alone and the lower you can keep your input costs early on the less financial implications there are if you lose the crop subsequently.

“I think a lot of people would be encouraged to take more of a risk with the crop if they thought they’re not going to lose out so much if things go wrong.

“You can then spend your money when you’re confident the crop is going to make it through.

“That said, we don’t generally spend anything on a PGR as a result of the seed rate and drilling date combination, although we will always use a three fungicide programme – an autumn one for phoma, one at stem elongation and then a sclerotinia spray mid-flowering.

“At harvest, we leave the crop to ripen naturally and then direct cut. I’d rather wait for crops to mature fully rather than dessicate them – you get less red seed and higher oil contents if you do.”

Although one of the most professional seed producers in the UK, David understands the attraction of farm-saving seed in the current production environment.

“If you can save money on seed to help reduce early expenditure, it makes a lot of sense and with a proven variety like Campus you can be assured it’s going to establish well and deliver consistent yields if you get your basic management right.

“A good conventional variety gives you greater flexibility of drilling date and cheaper cost of establishment, so an element of farm-saved seed should be very much a part of a grower’s future risk mitigation strategy.

Key to getting the crop through the first critical few weeks is choosing the right variety
David Passmore, Oxfordshire Grower

All told, David says he’s actually pretty positive about the future of oilseed rape in the UK.

“There are obvious issues, but as the area of the crop comes down so too will the amount of flea beetle.

“With less rape to manage, growers can be more picky with drilling date and management, as we are, and the better crops will become. These will then get noticed and more people should be encouraged to give it another go.

“At the end of the day there are very few, if any, break crops that are as profitable as oilseed rape so it’s important we stick with it and learn how to grow it to the best of abilities.”

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