Agronomists in the CropDoctor North project organised by Bayer have rued the loss of CTL – but as Grieg Baird, of Agrii, pointed out we can still farm without it.

“We have alternative multi-site protectants and azoles and SDHIs,” he told The SF, adding that the performance of multi-site protectant options is balanced out by their use in mixtures and programmes.

“No multi-site protectant has a working life of more two weeks and none of them are systemic. Once that two-week period has elapsed you’re relying on other actives to maintain protection. You might see difference in straight trials but when used in a programme, the differences are narrowed.

“Providing we use products in mixtures, keep spray gaps short and help minimise disease risk through cultural practices then we should be able to manage disease threats.”

James Howat, of Bayer, added that it might put greater focus on cultural techniques, plant health and application best practice going forward. “We know that stressed plants are more susceptible to disease. We also are beginning to understand more about the plant’s ability to prime itself to defend against disease and pest attacks.

“Many are already using variety rating and drilling date to reduce disease risk but I can see us going further. Tissue testing is giving us a better picture of nutrient deficiencies which can be remedied by tailored nutrition applications and further advances in application technology will improve field efficiency and help timing adherence.

"When Aviator (prothioconazole + bixafen) and Siltra (prothioconazole + bixafen) were launched they brought rainfast times down to minutes. New fungicides will also come along with enhanced formulation.”

John Murrie said primary azole rates were still important. “The decline in azole performance might mean some question their value but they have an important role in SDHI mixtures. Rates of prothioconazole and epoxiconazole have increased with the fall in efficacy but it hasn’t gone completely.”

Mr Howat added that SDHI resistance had evolved quicker at higher doses, but the issue was less pronounced with azoles. “Azole resistance isn’t so affected by dose and with three-quarter rates still giving respectable protective performance it is why high azole rates are advised in SDHI mixtures. The minimum recommended rates of Aviator and Ascra are formulated to do just that which is why they are a convenient option for growers,” he pointed out.