Golf Business News – Dollar spot survey reveals contagion pressures and actions

Syngenta published the findings of Dollar Spot State of the Nation Survey 2024. Key findings of the report highlight the role of Integrated Soil Management practices to reduce disease outbreaks, including nutrition, tillage, moisture management and fungicide timing.

Examining responses from more than 100 golf course managers, Syngenta Technical Managers, Glenn Kirby and Sean Loakes, reported that problems with the dollar have become more widespread – affecting all areas of the course and an extended part of the season.

“The most expensive area was considered to be a summer disease, but reports have shown that it can occur all year round, with the highest number of cases reported from March to October,” commented Sean Loakes.

“Furthermore, although it was often associated with tees, fairways and fairways that were less controlled, this report highlighted that the greens were actually the most affected areas.”

He also added that all types of grass will be affected, as management actions in the planted area will have a major impact on disease outbreaks, over animal species. Dollar spot outbreaks were reported in 81% of dominant fescue cultivars, compared to 58% of bent blends and 57% of dominant poa cultivars.

Correlating the zip code of the survey responses with local records of Smith-Kerns pressure, weather conditions that would be associated with dollar spot outbreaks, revealed that high pressure would indicate more diseases.

“However, it's not a clear correlation,” Sean said. “Other studies under long-term stress have reported no incidence of bucks, indicating that this disease can be effectively controlled with other weed control methods.

“Similarly, some studies with low climate stress have reported dollar spot diseases. This highlighted that the Smith-Kerns model is a useful guide to risk, but that the numbers must be interpreted along with all other actions when making decisions.”

For effective ITM techniques, frequent rolling, maintaining high soil moisture and providing high levels of nutrients are all associated with lower dollar spot rates being reported, Sean added.

“Results from the study showed a clear trend of higher incidence of reported diseases when grasses were managed with lower nutrient levels.

“However, it was not the only one, which shows that the dollar area can still be found in low nutrient management techniques, providing other ITM measures to avoid outbreaks,” he advised.

“Furthermore, although few outbreaks have been reported in lawns managed with high nutrient applications, they can still occur if lawn management practices and conditions contribute to disease.”

Answers to Dollar Spot State of the Nation Survey it also showed communication between managers to address low levels of soil moisture content (VMC) and the reported incidence of dollar spot.

Areas with a VMC management target of less than 15% reported the highest rates of outbreaks, over 70% of cases. When the responses of the areas managed in the upper VMC target area of ​​21 to 25% were examined, more than 60% of the subjects reported that there were no areas of the dollar outbreak.

“The survey responses showed a clear pattern that greater use of turf iron in rolling areas resulted in a decrease in dollar spot reports,” said Sean.

“In studies where the green has never been removed, the place of dollars was reported in 75% of the cases, while the practice decreased to 50% of the studies that went out five times a week. Most subjects (61%) reported that they were rolling two or three times a week.”

In the studies that have been going on almost every day, no incident of dollar spot has been reported. However, this was a very small proportion of survey responses (3%).

The survey identified no link between the levels of organisms and outbreaks in dollar areas, however there were indications that reduced heights could be associated with reduced levels of infection. “This is an aspect of the ITM strategy that needs further investigation,” he suggested.

Analysis of the Dollar Spot State of the Nation Survey shows that when greenkeepers are able to promote high fescue areas, they lower target moisture levels, reduce nitrogen use and increase cutting length, compared significantly to poa and gobile greens.

Greens containing fescue receive, on average, 40% less nitrogen compared to poa or bent greens. Fescue greens are also managed at a 4-5% lower VMC target and have an average cutting height of 3.9mm, which is 0.4-0.5mm higher than poa or bent greens.

“According to the findings of this report, it is possible that these management methods are playing into the hands of the dollars.

“Although the feeling is that fescue species are more tolerant of dollar spot, the management practices required to maintain them can result in the dominant areas being more vulnerable to this disease,” he warned.

The report revealed that the majority of sanitarians – about 70% – used fungicides as part of their dollar spot control strategy.

“Although in some cases management may consider that the dollar spot does not warrant mold control in all areas of the course, as the climate changes we need to consider how to keep damage to an acceptable level,” added Sean.

“New fungicide technology, better disease modeling to help improve timing and better application methods will help turf managers get the most out of them as part of their Integrated Turf Management strategy.”

Responses to the survey provided guidance on several actions turf managers can consider to reduce risks and mitigate the impact of this increasingly challenging disease.

Sean's top tips for reducing stress on the dollar area and better managing disease:

• Enough food
• Maintain humidity levels
• Normal rolling
• Low cutting height
• Be aware of disease-causing weather conditions
• Molding is timely and accurate
• Management throughout the year

“A better understanding of the effects of certain management practices on the risk of the dollar spot, can help motivate measures to reduce pressure in the future,” he concluded.

Following on from the dollar spot survey, the new Microdochium Patch State of the Nation Survey will seek to identify and share knowledge of management practices to help all turf managers effectively deal with widespread turfgrass disease. Complete the survey here.

Full Dollar Spot State of the Nation Survey 2024The report is available for download on the Syngenta Turf & Landscape website.