Thousand Cankers Disease is Widespread in Black Walnut in the Western United States

Fig. 2. Distribution of thousand cankers disease on black walnut (Juglans nigra) in the western United States. Counties highlighted in blue represent those in which Geosmithia morbida has been isolated from symptomatic trees. Counties highlighted in red represent those where symptoms of thousand cankers disease were observed, but where isolation of G. morbida was not attempted because trees were removed before samples could be collected. Some of the trees sampled for confirmation of G. morbida in Oregon are hybrids of J. nigra with J. hindsii.



Image from Plant Health Progress article:
Thousand Cankers Disease is Widespread in Black Walnut in the Western United States