Four New Host and Three New State Records of Dothistroma Needle Blight Caused by Dothistroma pini in the United States.

During 2010 and 2011, Dothistroma needle blight (DNB), also known as red band needle blight, was observed for the first time in Cass and Pembina counties in North Dakota (ND). In Pembina Co., DNB was observed in two sites in the Jay V.

Quantitative phenotyping of X-disease resistance in chokecherry using real-time PCR.

A quantitative real-time SYBR Green PCR (qPCR) assay has been developed to detect and quantify X-disease phytoplasmas in chokecherry. An X-disease phytoplasma-specific and high sensitivity primer pair was designed based on the 16S rRNA gene sequence of X-disease phytoplasmas. This primer pair was specific to the 16SrIII group (X-disease) phytoplasmas.

Development and cross-species/genera transferability of microsatellite markers discovered using 454 genome sequencing in chokecherry (Prunus virginiana L.).

Chokecherry (Prunus virginiana L.) (2n = 4x = 32) is a unique Prunus species for both genetics and disease-resistance research due to its tetraploid nature and X-disease resistance. However, no genetic and genomic information on chokecherry is available.

Characterization of X-Disease Phytoplasmas in Chokecherry from North Dakota by PCR-RFLP and Sequence Analysis of the rRNA Gene Region.

Genetic variation of X-disease phytoplasma strains from chokecherry (ChX) in North Dakota and nearby sites, and their relatedness with three standard strains of the X-disease phytoplasma group, eastern X-disease (CX), western X-disease (WX), and goldenrod yellows (GR1) phyto-plasmas, were studied. Primer pairs were developed to amplify the 23S ribosomal RNA (rRNA) gene and the 16S/23S spacer region. The rRNA genes (16S rRNA, 23S rRNA, and two ribosomal protein [rp] genes) and the 16S/23S spacer region were amplified by polymerase chain reactions.

Condition of Green Ash, Incidence of Ash Yellows Phytoplasmas, and Their Association in the Great Plains and Rocky Mountain Regions of North America.

About 50% of 1,057 green ash (Fraxinus pennsylvanica) systematically sampled in the Great Plains and Rocky Mountain regions had substantial dieback (>10% of crown branches with dieback), and the average growth ring width during the last 20 years was 2.9 mm. The overall condition of the population was rated fair.

First Report of Dothistroma septospora on Native Limber and Whitebark Pine in Montana.

Dothistroma septospora (Doroguine) Morelet (= Dothistroma pini Hulbary), the anamorph of Mycosphaerella pini Rostr. in Munk, has been reported to cause needle blight in 29 Pinus species and hybrids in North America, including limber pine (P. flexilis James) in plantings in Kansas, Nebraska, and Ohio.

Lilac Witches'-Broom in North Dakota.

Lilac witches'-broom (LWB), caused by the ash yellows (AshY) phytoplasma, was identified in common lilac (Syringa vulgaris L.) in Cass and Ransom counties in southeast North Dakota in 1997 and 1998. The infected plants were immature, naturally regenerating lilac in the understory of three 57- and 58-year-old Prairie States Forestry Project windbreaks that have lilac as a planted component.

Expression of Inoculum and Family Specific Responses in the Ponderosa Pine-Western Gall Rust Pathosystem.

Host-pathogen interactions in the ponderosa pine-western gall rust pathosystem were studied using seedlings from eight open-pollinated mother-tree families and Peridermium harknessii aeciospores from two geographically separate sources. Pregall symptoms occurred on seedlings by 4 days after inoculation (DAI). Gall occurrence was essentially complete by 230 DAI.