Observations on the Biology of Ophiodothella angustissima

Abstract

Ophiodothella augustissima causes a leafspot disease on shrubs of Vaccinium arboreum . In autumn, diseased leaves bearing lesions fall to the ground where they overwinter. These lesions contain perithecial initials that mature with the advent of warm temperatures and spring rains, conditions that also favor the development of new leaves on the host. Mature perithecia contain asci with ascospores that are forcibly ejected upward onto young host leaves, which they infect. These new lesions grow and produce an acervular stage that forms numerous conidia that spread the disease throughout the plant during the summer. The timing of these events is determined by weather conditions, especially rainfall. As infected leaves dehisce in autumn, they remain beneath the shrubs, where they overwinter, ready to begin the cycle again the following spring.