Alternative Hosts in the Families Poaceae and Cyperaceae for pv. , Causal Agent of Bacterial Leaf Streak of Corn.

The bacterial pathogen pv. was first reported in the United States causing bacterial leaf streak on Nebraska corn () in 2016. The bacterium is also known to cause disease in sugarcane, grain sorghum, broom bamboo, and various palm species. The objective of this study was to identify alternative hosts for pv. among plants commonly found in corn growing areas of the United States. In repeated greenhouse experiments, 53 species of plants found in the United States that had not been tested previously for susceptibility to pv. were inoculated with the pathogen and monitored for symptom development. Eleven species in the family Poaceae exhibited symptoms: oat (), rice (), orchardgrass (), indiangrass (), big bluestem (), little bluestem (), timothy (), sand bluestem (), green foxtail (), bristly foxtail (), and johnsongrass (). Yellow nutsedge () in the Cyperaceae also was a symptomatic host. In addition, endophytic colonization by pv. was found in three asymptomatic alternative hosts: downy brome (), tall fescue (), and western wheatgrass (). Experiments were also conducted in the field to determine the potential for alternative hosts to become infected by natural inoculum. Symptoms developed only in big bluestem and bristly foxtail in field experiments. These results suggest that infection of alternative hosts by pv. can occur, but infection rates might be limited by environmental conditions.