Microdochium patch (fusarium) pressure has been incredibly high already this season, with widespread outbreaks reported across the UK.
It has been a double whammy of unseasonably mild temperatures and prolonged leaf wetness that are highly favourable for disease development, combined with continued soft leaf growth in the dull, overcast conditions that has been especially susceptible to infection without a fungicide protection, warns Syngenta Technical Manager, Sean Loakes.
It’s been all the more unprecedented since, for the most part, greenkeepers had felt they have the Integrated Turf Management cultural practices in place to manage the pathogen, according to findings of the Syngenta Microdochium State of the Nation report, published this week.
The survey has revealed that, with changing climate conditions, outbreaks of microdochium are occurring more widely across the UK, as well as for longer than historically experienced. Disease pressure was now reported to be seen building significantly in August, and peaking through October and November.
“Notably the reports of pressure and damage also extended far longer into the spring than would have been normally expected – possibly as a consequence of intense pressure and slow turf growing conditions holding back recovery,” he points out.
“While 96% of respondents reported incidences of microdochium last year, over a third felt they always had it in control. For two-thirds it was still more than liked and in 25% was impacting on the putting surface or causing significant damage.”
“That puts extra focus on being able to accurately predict disease pressures for the current season, along with the capability to quickly adapt strategies to cope,” Sean advises.
Greens surfaces were reported to be the most widely affected, by three quarters of respondents, however approaches, tees and fairways were all widely hit; possibly where reduced fungicide applications or ITM actions left turf more exposed.
Key findings include identifying Poa annua dominant greens as the species most susceptible to microdochium. While fescue was among the least affected species, it was notable that where infection did occur it was rated as particularly damaging.
For Integrated Turf Management (ITM) practices, dew removal was seen as by far the most critical and having greatest beneficial effect in drying leaf surfaces. Winter nutrition, iron, turf hardening products and fungicides were also ranked highly in ITM strategies, with lesser importance for wetting agents, biostimulants, rolling and pigments.
Detailed analysis, to correlate ITM actions of individual respondents to the reported incidences of microdochium outbreaks and severity, surprisingly identified no clear relationship between organic matter and disease. Surprisingly there was also no clear correlation between height of cut and disease, although the survey asked about mower bench settings, which may be different to cut height in practice during winter.
“This indicates the possibility that other factors, including environmental conditions, cultural practices, or specific grass species characteristics, might play more significant roles in influencing microdochium disease dynamics,” he believes.
Interestingly, the survey suggested a strong relationship between the number of mechanical operations, including rolling and cutting, with reduced disease incidence. That may be a factor of improved drying of leaves, but Sean suggested may also be associated with higher standards of more intensively managed surface reducing disease pressure.
“The Microdochium State of the Nation report provides a fascinating insight into the current impacts of the disease, along with identifying common themes and practices that are helping greenkeepers to get a grip on its successful management,” Sean advocates.
The comprehensive survey gained participation from over 90 greenkeepers and turf managers. It provided a robust data set that allowed for analytic conclusions relevant to turf management in the UK and Ireland.
“From what was once the predominant scourge of winter turf surface quality and the most widely reported disease, for many microdochium is now viewed as a manageable issue,” he suggests.
“However, as highlighted this season, with changes in climatic conditions and adaptations in management regimes to counter other disease threats, as well as meeting higher player expectations, the lessons learned will have important implications to integrate into future strategies.”
The full Syngenta Microdochium State of the Nation report is available to download now
