Needle Blight on Spruce in North Dakota Caused by Lirula macrospora.. J. A. Walla, Department of Plant Pathology. North Dakota State University. Fargo 58105. Plant Disease 68:1016, 1984. Plant Dis. 68:1016. Accepted for publication I August 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-1016c.
Lirula macrospora (Hartig) Dark. is causing a needle blight of spruce (Piceapungens Engelm. and P. glauca (Moench) Voss) in several 16- to 35-pr-old farmstead shelterbelts and urban landscape piantings in North Dakota. Aesthetic value has been destroyed and lower branch dieback has occurred on some heavily infected trees. Identity of the pathogen was confirmed in 1980 by J. Staley. currently at Western Washington Research and Extension Center. Puyallup. In North Dakota. symptoms first appeared in October on second-year needles as yellow to brown bands. Needles were entirely reddish brown by November. and pycnidia were present the following April. In June of their third year. needles were light brown and hysterothecia were present. Hysterothecia began sporulating in June on 4-yr-old needles when current-sea3on shoots were 5-8 cm long; sporulation was associated with measurable precipitation. By August of their fourth year, needles were gray and shriveled but remained attached. L. Macrospora in North Dakota appears to fit Hartig's type 2 pattern of development (Phytopathological Classics 12, 1975).