WHILE a lost of arable farmers remain sceptical about growing oilseed rape, a well-known agronomist is convinced there's a bright outlook for the crop.

Despite facing increased slug threat and a potential light leaf spot (LLS) epidemic, it could be a valuable crop this season, according to Frontier's Mike Barry. He maintains that this season it might be the best break crop performer, justifying agronomic investment.

“It can be a bit of a ‘yo-yo’ crop, but with grain prices where they are, OSR is attractive right now,” he argued.

With oil bonus added, the potential rapeseed price for next harvest is currently around the £300 per tonne mark and that's why he is urging growers to give crops every chance of coming through the winter well.

As far as disease is concerned, he is hopeful that a single LLS spray will be sufficient for much of his area and that it can be combined with an application of Kerb (propyzamide) if ground temperatures allow. But, delaying fungicide applications can be risky.

“If soil temperatures don’t allow for a combined pass then split fungicide and herbicide treatments. If LLS gets established, the damage is done,” he cautioned.

He said that the disease is like septoria in wheat. “It has a similar latent phase. The longer it is in the ground, the more exposure it has. You can’t see the disease, but it is present within the leaf.”

A Bayer-funded AHDB spore trapping project co-ordinated by Weather Innovations has shown that spores are being dispersed from August. This will have continued as cultivations disturbed OSR trash.

With many crops going into the ground early, there has been plenty of time for crop infection he feels, so autumn fungicide choice will come down to the level of plant growth regulation needed.

If growth needs to be checked, then he reckoned growers should up the dose of tebuconazole and opt for Corinth (prothioconazole + tebuconazole). If not, it will be straight prothioconazole (Proline275) or Prosaro (prothioconazole + tebuconazole).

“Tebuconazole is still active, but you really need the potency of prothioconazole, and you’re getting good phoma activity too,” he pointed out.

While dry conditions in some parts of the country will have eliminated the need for a PGR, he said split sprays might be useful. “Northumberland and some Border areas have been that bit wetter. Leaf wetness will have meant an early spray to check the disease," he said.

"However, I would back it up with a second dose to help see the crop through winter. Having an early application also means that you don’t need such a robust dose. A half rate might be sufficient.”

Where effective slug and disease control strategies have been applied he also stressed the importance of getting nutrition right. Most should have received autumn nitrogen and starter phosphate either as band applied liquid or DAP.

“Both are effective at increasing growth rates and reducing risk in that critical early establishment phase. Autumn foliar nutrition is also very important and the main nutrients to focus on are manganese, boron and molybdenum.

"Remember that OSR is also responsive to potash and has a huge requirement so where soil indexes are low bear this in mind,” he said.

Ideally, the aim is to achieve a canopy with a GAI of 3.5 at flowering. The level of canopy manipulation needed and nitrogen timing and rates can only be determined post winter but he has a note of caution. “Excessive and early nitrogen will only result in denser canopies, restricting light penetration on the run up to flowering,” he added.