Several North American walnut species (Juglans spp.) are threatened by thousand cankers disease which is caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and its associated fungal plant pathogen, Geosmithia morbida M. Kolarík, E. Freeland, C. Utley and N. Tisserat sp. nov. Spread of this disease may occur via movement of infested black walnut (Juglans nigra L.) wood. This stu...

embryo culture were used to produce inter specific walnut hybrid plants between juglans nigra l. and j. regia l. developed ovaries were collected from j. rejia female flowers which were pollinated with j. nigra pollen grain by high dusting on a mature tree. in order to isolate embryos, exocarps were aseptically removed. isolated embryos from ovules at different developmental stages were transfe...

Thousand cankers disease (TCD) is a newly recognized disease of various species of walnut (Juglans). Black walnut (Juglans nigra) is particularly susceptible to TCD and during the past decade it has devastated plantings of black walnut in most western states. In July 2010 thousand cankers disease was found over an extensive area around Knoxville, Tennessee, the first finding of TCD within the n...