Ventenata dubia's native range and consideration of plant pathogens for biological control.
Ventenata [Ventenata dubia (Leers) Coss.] is a nonindigenous, invasive grass in the inland Pacific Northwest (PNW) of the United States. It appears to be present in the PNW without any evidence of disease expression. Surveys of V. dubia in the PNW (Idaho, Montana, Oregon, and Washington) were entirely negative for fungi, including types of pathogens that might be expected in grasses (e.g., rust, powdery mildew, choke). In Europe, where V. dubia is native, fungi were documented (i.e., Septoria ventenatae Sandu, Tilletia fusca Ellis & Everh., and Tilletia elisabethae T. Denchev & Denchev) on V. dubia. In its native range there likely are natural enemies that may limit V. dubia abundance, and these may include fungal pathogens. Pathogens of V. dubia from its native range may hold potential for use as classical biological control agents in North America, and if deemed safe, could be introduced. To ascertain V. dubia's native range, we compiled data from herbarium specimens, consulted with herbarium curators in the region, and searched relevant literature. We found that V. dubia primarily is reported in southern Europe and western Asia. Ventenata dubia has been reported only occasionally from North Africa in Algeria and Morocco. The common name "North Africa grass" likely originated from references to V. dubia in the 19th-century botanical explorations in Algeria of the French botanist, Ernest Cosson, who published the current scientific name based on a preexisting name in 1854. Another finding of interest is that the latitudinal range of collections from Europe and North Africa of V. dubia spans Tunisia to Finland. The plant may thus be adapted to a range of environments, indicating it could become more widely distributed in North America. Efforts to search its native range for pathogens should also consider the range of environmental conditions found within its native and introduced ranges.