Submitted to: Forest Microbiology
Publication Type: Book / Chapter
Publication Acceptance Date: 8/24/2021
Publication Date: N/A
Interpretive Summary: Foliar nematodes can cause millions of dollars in damage to forestry and ornamental plant commerce each year. Beech leaf disease was an emerging, mysterious forest disease for 8 years before 2020 when USDA scientists from Beltsville, MD, Morgantown, WV, the state of Ohio and the province of Ontario, Canada, reported identification and transmission of symptoms by a damaging, fast-moving foliar nematode. This nematode subspecies was new to North America with the original species description from Japan in 2019. This chapter provides a summary and update of the high resolution anatomical and molecular detection of the nematode and its ecology. This information will assist plant pathologists and foresters to conduct research needed to reduce the spread of this invasive pathogen.
Technical Abstract: American beech trees are critical sources of food and shelter for wildlife in northeastern U.S. forests. Beech leaf disease is an emerging forest disease first discovered near Lake Erie by Cleveland Metroparks biologists in 2012. Plant scientists from the U.S. and Canada demonstrated symptoms could be transmitted in the greenhouse by nematodes new to North America, providing a focus for further research. This rapidly advancing disease recently reached the Atlantic coast up through Maine and down to West Virginia. This chapter documents high resolution fluorescent and low-temperature scanning electron microscopic images of diseased leaves that show reduced chlorophyll in infested leaves, damage and distortion of internal and external leaf tissue, and describes mites entwined with nematodes that could possibly transmit the disease. Various images of symptomatic leaves and a discussion of possible microbial co-factors that may relate to increased virulence in North America is included.