"Pseudomonas helianthi" is a Gram-negative plant pathogenic bacterium that infects a variety of plants. It was once considered a pathovar of Pseudomonas syringae, but following DNA-relatedness studies, it was recognized as a separate species and P. syringae pv. tagetis was incorporated into it, as well. Since no official name has yet been given, it is referred to by the epithet 'Pseudomonas helianthi' .