Phytophthora root and crown rot, a devastating disease impacting English lavender, has become a significant threat to commercial production. Recent research conducted under controlled greenhouse conditions has evaluated the effectiveness of various fungicide applications in managing this disease. The findings reveal that specific treatments can substantially reduce disease severity, thereby enhancing plant survival and vigor.
This research comes at a crucial time as Phytophthora nicotianae, one of the most studied species of the pathogen, continues to affect lavender crops not only in the United States but also across Europe, including Spain, Italy, Bulgaria, and Greece. First identified in 1896 as a pathogen on tobacco, P. nicotianae has since been recognized for its pathogenicity across 255 plant genera and 90 families. Symptoms of infection in lavender include grey discoloration and wilting of foliage, root rot, vascular discoloration, and eventual plant mortality.
Research Findings and Implications
The study offers practical solutions for lavender growers by identifying the most effective chemical management options. These findings contribute to the development of integrated disease management approaches, combining fungicides with cultural practices to improve long-term plant health. Dr. Dlugos, a Senior Research Specialist in plant breeding at Holden Forests & Gardens, emphasizes the importance of these results for maintaining high-quality lavender production.
Dr. Dlugos, who earned his Ph.D. from Clemson University, conducted this research as part of his dissertation project. His expertise in plant disease management is instrumental in this ongoing research, which is being conducted in collaboration with the US Lavender Growers Association and supported by the USDA Floriculture and Nursery Research Initiative.
Expert Insights
Dr. Bridges, a Distinguished Alumni Professor of Mathematics and Statistics at Clemson University, and Dr. Jeffers, a Professor of Plant Pathology and State Extension Specialist, have also contributed to this research. Their combined expertise in statistics, data analysis, and plant pathology ensures a comprehensive approach to managing diseases in ornamental plants and trees.
According to Dr. Jeffers, “The integration of fungicides with cultural practices is key to sustainable lavender production. Our research aims to minimize losses and promote the sustainability of lavender cultivation nationwide.”
Broader Context and Future Directions
This study is part of a larger research initiative to identify and manage Phytophthora species causing root and crown rot in lavender. The ongoing project seeks to enhance the sustainability of lavender production by providing growers with effective tools and strategies.
The American Society for Horticultural Science (ASHS), established in 1903, plays a pivotal role in promoting scientific research and education in horticulture. With thousands of members worldwide, ASHS represents a diverse group of horticultural professionals, including scientists, educators, and industry experts. For more information, visit ashs.org.
The full study is available on the ASHS HortScience electronic journal website at https://doi.org/10.21273/HORTSCI18302-24.
As the research progresses, the collaboration between academic institutions and industry associations continues to be vital in addressing the challenges posed by Phytophthora root and crown rot. The ongoing efforts aim to equip lavender growers with the knowledge and tools necessary for effective disease management and sustainable production practices.
