Dollar spot disease pressure is now increasing, as temperature and humidity rise resulting in prolonged periods of leaf wetness, warns Syngenta Technical Manager, Sean Loakes. Speaking to course managers with ICL at the prestigious 72-hole championship Melbourne Club, on the Brocket Hall Estate in Hertfordshire this week (3 June 2025), he highlighted that although overall dollar spot pressure has been relatively low so far this season with the dry spring, early symptoms are beginning to be seen in disease hot spots.

“Turf management actions now, with cultural controls and Ascernity fungicide treatments, can reduce the risk and prevent damaging loss of grass cover or surface quality,” he advised. Sean highlighted the danger of dollar spot is becoming more severe, since the pathogen appears to be developing at lower temperatures and with shorter periods of leaf wetness. “Researchers who designed the original forecasting model now report the evolving pathogen appears to be developing with shorter periods of suitable leaf wetness and temperature,” he said.

The effect would be a double whammy of more frequent conditions for the disease occurring, and the capability for the disease to go through its lifecycle faster.

“For courses in high pressure situations that find they have been consistently hit earlier by dollar spot, it may be necessary to target treatments at a lower pressure threshold, for example,” he advocated.

“Tracking the Smith Kerns model on Turf Advisor gives advance warning of pressure periods,” he said. “But be aware of localised risks on your course, as irrigation and microclimates will increase periods of leaf wetness that pushes up pressure – and can leave turf open to attack.”  Preventative Ascernity fungicide applications can crucially protect turf through high-risk periods.

Available as part of the AIM pack, it could cost-effectively cover the whole season strategy. Golf course trials in Cambridgeshire last season proved how the Syngenta fungicide programme, including Ascernity followed by Instrata Elite, effectively halved any signs of disease damage on the surface – resulting in less than 4% infection in the treated area, compared to over 16% in untreated at the end of the reported assessments.

“Used in an Integrated Turf Management programme, along with the biostimulant boost of a Turf Health Plan, it puts you in the best place to stop dollar spot damage occurring,” he added.