Growers are being urged to test and/or treat farm-saved spring crop seed for diseases such as loose smut and seed-borne net blotch.

With winter cereal drilling only around 70-75% complete before autumn storms put a stop to further drilling for many growers across the UK, a larger-than-expected spring crop is now being forecast.

Already most certified spring cereal crop seed has been sold with it virtually impossible to source if you haven’t already done so, traders are saying.

That leaves farm-saved seed as almost the only possible option for growers still needing to source spring crops to drill fields that were intended for winter crops, unless a weather window opens for a late-sown winter crop.

“We’re expecting farm-saved spring seed use to be up massively on farm, especially spring barley,” says Agrii farm saved seed business manager Mark Taylor.

“Treatment demand could be up by 30-40% on a typical spring cereal season,” he estimates. 

Those who are intending to drill grain from their own store are strongly advised to get a full germination test and indicate to the lab where glyphosate may have been applied as a desiccant. While the latter is far-from-ideal, any abnormal seedlings can be adjusted for by increasing the seed rate.

Where decisions on a base single purpose seed dressing for either allocated spring barley certified or farm-saved seed, Agrii seed technical manager David Leaper suggests that two diseases drive the choice: loose smut and seed-borne net blotch.

“Over the past five to six years there is evidence to suggest a loss of prothioconazole sensitivity to loose smut,” he says.

That, coupled with the loss of approval for some actives used for seed treatments, has led to Agrii to transition away from prothioconazole-based seed treatments to Rancona i-Mix (ipconazole + imazalil).

“There’s clear evidence to show that the level of loose smut activity you get from ipconazole is better than prothioconazole,” he says. “So that puts Rancona i-Mix as the top technical treatment for control of loose smut, which is the key priority disease in spring barley.”

The other key disease is seedborne net blotch. “You can get degrees of varietal resistance to net blotch from resistant or moderately resistant to susceptible, and while crops can pick up net blotch from green bridges and transfer from stubbles, we know the seed-borne route is quite important.

“Our trials at Agrii Focus have shown that the ipconazole / imazalil combination has the best control of seed-borne net blotch, so those two diseases are the reason for choosing Rancona i-Mix.”

Leaf stripe will also be controlled by Rancona i-Mix, he says, but is rarely picked up in seed tests, while Fusarium and Microdochium nivale tend to be less of a problem in a spring crop drilled into warming soils.

Where growers are considering not treating with single purpose seed treatment, David recommends a seed test is used to check for disease. Around 14% of farm-saved spring barley seed was not treated with fungicidal seed treatments last spring, and those crops will be most at risk from seed-borne diseases, he says.

“You can go from trace levels or no apparent disease, with something like loose smut, to significant crop effects within three seasons, if you’re using non-treated seed without testing.”

Previous crop seed treatment choice could also be a factor to consider, even if you’re home saving last year’s bought-in certified seed, he adds.

“If your certified seed was supplied with Beret Gold (fludioxonil), which is a good treatment for seedling blights but has very little activity against loose smut, you probably want to get it tested, if you’re considering not treating.”

Nutritional seed treatments should also be considered, David adds. Research by Agrii and Lancrop Services identified through analysis of crop samples at different growth stages that spring barley clearly required adequate manganese, zinc and copper during early stages of growth.

“These can be applied as a seed treatment as well as in a starter fertiliser, and help fill that hunger gap the crop goes through before it gets its roots down to exploit the rhizosphere.”

While Rancona i-Mix has lost its approval in the EU, it is still fully approved and available across mainland Great Britain, confirms Jo Hawke, UPL trials manager.

“It’s approved for both spring barley, including for malting barley, and spring wheat. We have enough supply to meet the increased demand we expect ahead of this spring’s plantings.”