LEADING agronomists are advising 'Don’t give up on backward winter oil;seed rape' even though establishment has been highly variable.

Crops drilled in August have romped away but those drilled later following harvest delays are a bit further behind and Agrii agronomist, Greig Baird and Bayer’s Grant Reid, pointed out that some crops are only at the two-leaf stage.

Both agronomists have recorded surprisingly low soil temperatures for the time of year. Even in the Borders, some soils were below 10°C by early October. However, they believe crops can recover in time to see them through winter.

Mr Baird said he is putting his focus in ‘kick starting’ backward crops. That means checking root condition and where crops are actively growing, take immediate nutritional action.

“I think many crops will benefit from a 30 kg/ha dose of N and I’d check soils for phosphate, potash and boron. All of those will help stimulate root development and this is going to be vital in encouraging growth.”

Mr Reid agreed, pointing out that root establishment is more important than leaf size. “The root collar needs to be at least 1cm going into the winter as it is the engine to drive spring growth. Even if leaves are small, the plant will recover.”

Kick starting crops at the earliest opportunity is necessary to cope with increased slug pressure and light leaf spot (LLS), added Mr Baird.

“The dry spell in early spring delayed breeding, rather than impair it. But rain from late May onwards was ideal. In addition to the weather hindering harvest and cultivations, there's also be less subsoiling this season and seed beds were not as good as last autumn. We are likely to face a higher slug burden,” he warned.

Obviously hybrid vigour does help and he said variety choice is a vital factor in OSR success. “We have some very good conventional varieties but in challenging conditions, the vigour of hybrids really comes to the fore. Varieties like InVigor1035 are particularly suited to the challenging conditions we can face here.”

All crops will get protection against LLS and the only real decision is whether a top up spray is needed. “I wouldn’t want to leave any crop unprotected against LLS and all crops are likely to get Kestrel (prothioconazole + tebuconazole).

"The conundrum is whether a second autumn spray is needed or if a single dose will see the crop through to spring. Bigger crops might grow away from the disease but it can easily spread through less developed crops.”

Mr Reid agreed that LLS pressure could be higher. He pointed to the amount of OSR that came through last season. “For many, OSR was a good earner last season. We had sun and rain at the right time and some very good crops come harvest. But that has left a lot of trash around for the disease to infect from.”

His advice is to think about chemical rates: “Prothioconazole remains the most effective LLS active, but like any product rate is important. With Kestrel, you have two effective LLS actives but if going with straight prothioconazole, I would look for 130g/ha in high risk situations, this is a 0.46 l/ha dose of Proline275.

"It can be a long gap to the start of stem extension and you can’t afford for the disease to get in,” he concluded.