Depending upon weather conditions, pathogen population and walnut variety, walnut blight caused by the bacterium Xanthomonas arboricola pv. juglandis (Xaj) can cause significant crop loss. Blight damage in later leafing varieties largely depends on how high the overwintering population of inoculum built up on bud scales. Initial inoculum in dormant buds can be used to predict subsequent disease severity. Continue reading →