The SpotCheck initiative is again open for OSR growers to send in leaf samples to check for key oilseed rape diseases.

Run by Bayer, it has a new, simplified sample pack request process for this season. Growers and agronomists can request a sample pack direct from Bayer’s website. Leaf samples will be assessed by ADAS experts for signs of light leaf spot and other key diseases, with the results helping growers to adapt their fungicide programmes accordingly.

LLS is an airborne polycyclic disease, capable of several infection cycles each season. The severity and incidence of the disease varies from year to year and is driven by weather conditions. Temperatures between 4-20°C and wet conditions are ideal for infection and spread within the crop. It can be difficult to spot and tiny sugar-like spores can occur on either side of the leaf.

Read more: Growing oilseed rape: Take action now to beat LLS next year

Rosalind Martin, the fungicide campaign manager for Bayer, said: “Fungicides perform best when applied in a protectant scenario against light leaf spot, so it’s important to get the timing right. If growers can get identify the disease in the early stages of infection, decisions can be made about fungicides in a timely way, to protect the crops yield potential through winter.”

Launched in 2017, SpotCheck had helped hundreds of growers to make better-informed decisions on autumn and spring fungicide applications.

To request a sampling pack, growers and agronomists just need to complete a short form via the Bayer website. A pack will arrive in the post direct to your preferred address, which can be returned to ADAS with leaf samples for analysis.

Results will be emailed to participants within seven working days of leaves arriving at the laboratory. It is run in partnership with ADAS and Philip Walker, ADAS' arable plant pathologist, said that prevalence of light leaf spot in oilseed rape crops has been increasing since the initiative began.

“Traditionally, light leaf spot was mainly thought to be a disease problem for crops in the North of England and Scotland. However, results from samples assessed since 2017 have shown positive signs of disease from all oilseed rape growing regions, indicating that light leaf spot is now endemic across the UK," he said.

Read more: Bayer SpotCheck highlights LLS risk

“At the end of March, 2021, LLS was found in 59 out of 60 counties tested, covering most of the oilseed rape growing areas of England, Scotland and Wales. In addition, the number of samples that have tested positive has gradually increased year on year, despite the total number of samples received remaining roughly the same.

"In 2018 and 2019, 49% of samples tested were positive for light leaf spot, increasing to 68% in 2020, and 79% in 2021,” pointed out Mr Walker.

Warm, wet winters in the previous couple of years had led to an increased incidence and spread of the disease. Given the potential for a high amount of inoculum to be present this autumn, growers should remain vigilant and regularly monitor crops.