Off the Record: Pioneering the future of dollar spot management

Recently, the golf course superintendent community has witnessed significant progress in the battle against dollar spot. Through the collaborative efforts of university researchers, the latest developments offer promising insights and innovative strategies for managing this prevalent disease.

Mike Kenna, Ph. D.

This article provides an update on the current projects, new research initiatives and future events dedicated to advancing our understanding and control of dollar spot in turfgrass.

Cultural practices

Following extensive research conducted over the summer of 2022, Fereshteh Shahoveisi, Ph.D., University of Maryland, is preparing a peer-reviewed article on dollar spot cultural practices.

She will submit this pivotal work for the 2025 International Turfgrass Research Conference (ITRC). The article will summarize cultural strategies to mitigate dollar spot impact on putting greens and fairways. Golf greens had minimal differences in dollar spot and more significant variances were on fairways, with nitrogen application and dew removal exhibiting the largest impacts.

Despite these improvements, stacking cultural practices did not sufficiently suppress dollar spot to commercially acceptable levels.

Bentgrass cultivar survey

To encourage the adoption of disease-resistant cultivars, a survey was completed to identify factors that superintendents use when selecting bentgrass cultivars. The findings are interesting, and Ming-Yi Chou, Ph.D., at Rutgers University, has taken the lead in synthesizing these results into a comprehensive publication.

Potential journals for publication include the Journal of Extension and HortTechnology, among others, highlighting the survey’s significant contributions to the selection and management of bentgrass cultivars concerning dollar spot resistance.

Host resistance

Initiated in 2021, across seven locations, this project has provided valuable data on the resistance of various bentgrass cultivars to dollar spot.

Notably, Coho emerged as a superior cultivar in terms of resistance, compared to Shark and Penncross. The findings, particularly from Michigan State and Wisconsin, underline the importance of cultivar selection in dollar spot management strategies. The project’s continuation into a third year is under discussion, emphasizing the commitment to understanding and improving host resistance.

Improved cultivars

Launched in 2023, this new study aims to adjust the Smith-Kerns Dollar Spot model thresholds for cultivars with varying resistance levels. Preliminary results from five locations show that spray thresholds could be significantly increased for resistant cultivars like Coho, promising reductions in fungicide applications and associated costs.

Resistant cultivars

This project is investigating effective bentgrass conversion strategies to help reduce fungicide use. Initial findings from 2023 laid the groundwork for continued research into dollar spot differences between treatments and the establishment of resistant cultivars.

Looking ahead

John Inguagiato, Ph.D., at the University of Connecticut, introduced a novel research initiative exploring the relationship between aerification practices and dollar spot development, sparking interest among fellow researchers.

The researchers will reconvene at the Dollar Spot Conference in 2025, aimed at addressing challenges and knowledge gaps in dollar spot management. The positive response to the 2025 conference underscores the collective commitment to advancing turfgrass science and management strategies.

The collaboration and dedication of researchers and professionals in this field are essential to developing effective, sustainable strategies to benefit golf course superintendents globally.