Richard T. Olsen

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Hemlock (Tsuga) species and hybrids were evaluated for resistance to the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). The adelgid was accidentally introduced from Asia to the eastern United States, where it is causing widespread mortality of the native hemlocks, Tsuga canadensis (L.) Carrière and Tsuga caroliniana Engelm. These two(More)
PREMISE OF THE STUDY Exotic diseases are threatening many North American tree species, and management of diseases requires understanding the biology of the host as well as the pathogen. Ulmus americana is a widespread dominant tree of eastern North America that has been widely planted as an ornamental and shade tree. Populations of the species have suffered(More)
A diverse collection of germplasm representing 24 taxa from Catalpa sect. Catalpa Paclt and sect.MacrocatalpaGrisebach, Chilopsis D. Don, and ·Chitalpa Elias & Wisura were screened for susceptibility to powdery mildew (PM) incited by Erysiphe elevata (Burr.) U. Braun & S. Takam and feeding by catalpa sphinx larvae (CSL), Ceratomia catalpae (Boisduval). PM(More)
UNLABELLED PREMISE OF THE STUDY Genic microsatellites or simple sequence repeat (genic-SSR) markers were developed in boxwood (Buxus taxa) for genetic diversity analysis, identification of taxa, and to facilitate breeding. • METHODS AND RESULTS cDNA libraries were developed from mRNA extracted from leaves of Buxus sempervirens 'Vardar Valley' and(More)
A taxonomic revision of Catalpa (Bignoiaceae), a genus of perennial trees frequently used in horticulture as garden and street trees, is provided. Eight natural species and two hybrid species are recognized, four in sect. Catalpa, four in sect. Macrocatalpa, and two hybrid species in sect. Catalpa. Although C. punctata has been used for one of the tropical(More)
Boxwoods (Buxus L., Buxaceae) are popular woody landscape shrubs grown for their diverse forms and broad-leaved evergreen foliage. We used genic simple sequence repeat (genic-SSR) markers to assess genetic diversity and relatedness of 275 accessions from the National Boxwood Collection at the U.S. National Arboretum. Flow cytometry was conducted to(More)