Thousand Cankers Disease (TCD) of Juglans and Pterocarya (Juglandaceae) involves a fungal pathogen, Geosmithia morbida, and a primary insect vector, Pityophthorus juglandis. TCD was described originally from dying Juglans nigra trees in the western United States (USA), but it was reported subsequently from the eastern USA and northern Italy. The disease is often difficult to diagnose due to the...

The bacterial species Xanthomonas arboricola contains plant pathogenic and nonpathogenic strains. It includes the pathogen X. arboricola pv. juglandis, causing the bacterial blight of Juglans regia. The emergence of a new bacterial disease of J. regia in France called vertical oozing canker (VOC) was previously described and the causal agent was identified as a distinct genetic lineage within t...

MONG species of insects that have been used for genetic studies, there Aoccasionally appear adults which are composed of two or more different genomes. In Drosophila melanogaster, where most of these mosaics were of the gynandromorph type, it has been shown that elimination of an X chromosome during early cleavage was involved (MORGAN and BRIDGES 1919; PATTERSON 1931). In a few instances, ferti...