Light leaf spot in oilseed rape has taken off this spring in Scotland and northern England, according to Bayer’s SpotCheck initiative.

This provided growers and farmers with the opportunity to have leaves analysed for LLS for free by ADAS and since January more than 100 OSR samples have been provided from the across Scotland and the Borders.

The results confirm what many suspected and most samples were positive and that the disease is widespread across the region.

One agronomist who took advantage of the service is Frontier’s Douglas Gray. He found it useful to confirm his suspicions in the field. “Due to its latent phase you might not always see symptoms. But given the weather we’ve had, I’ve been on the lookout for the disease," he said.

"SpotCheck has given us the opportunity to confirm the presence of the disease, even if symptoms haven’t expressed themselves.”

His concern now is to protect new foliage. “In many seasons, the crop can grow away from the disease, but development has been slowed by the cool conditions. There is the danger the disease could easily spread up the plant."

He said the best counter is to think of fungicide rates at stem extension, especially where autumn treatments were missed or compromised. “When you look at the data from the samples I supplied, those where an autumn application wasn’t possible returned the highest incidence.

"What’s important now is to keep the disease from moving up the plant and eventually into the canopy. My view is that if you cut rates of a product, like prothioconazole, you cut persistence too.”

Bayer’s Grant Reid said the initiative had been a huge success and showed how widespread the disease was. “The results are similar from the Highlands to the Borders. We’ve recorded high incidence from both areas and across numerous varieties, not just susceptible ones,” he added.

Like Mr Gray, he is concerned about keeping the disease where it is. His main worry is workload and he said growers should act as soon as the opportunity presents itself. “There’s spring sowing to be done and winter crops are still to get T0s, spring herbicide applications and another fertiliser dressing. It might be sensible to treat ahead of stem extension.”

Mr Gray wanted to see SpotCheck continue for next year. “We’re crop walking anyway, so it’s not particularly onerous to put a few samples in a bag. And it was quick. If I sent my samples off on Monday, I normally had a result by Wednesday.”

Workload is also a concern for fellow Frontier agronomist, Peter Forster. “Probably, at the moment, we are two weeks behind where we were last year. But with warmer weather these crops will pick up the nitrogen and they could race through growth stages."

He said an SDHI at T1 is probably essential for most winter cereals. “I think many will omit a T0 with winter barley, given the number of tasks totting up. However, PGR and manganese will be important for tiller numbers.

"I am seeing some net blotch, rhynchosporium and with the harsh weather plenty of stem-based disease. I think this combination means that a SDHI will justify itself.

“Winter wheat crops that got a T0 spray will help buy some flexibility at the T1, but early sown septoria susceptible varieties like Barrel, Zulu and Myriad, will need a close eye on them.”

With a shorter than usual interval between T0 and T1 possible, he said not to move away from growth stage recommendations. “You must protect leaf three and delaying applications could see septoria get established by the time you get into the crop. Make sure the T1 is timed for GS31/32,” he warned.