New bacterial disease of ornamental asparagus
Ornamental asparagus (Asparagus virgatus, A. setaceus, A. macowanii and A. densiflorus) are grown in Florida (US), and are popular cut foliage crops. In April 1995, dark green to brown water-soaked lesions were observed on stems of Asparagus virgatus in Volusia County in Florida. Lesions varied in length from a few millimetres to one centimetre. Preliminary studies on pathogenicity, host range and metabolic characteristics showed that the disease is probably caused by a xanthomonad bacterium (Xanthomonas campestris). It seems that the metabolic characteristics of most strains isolated from several A. virgatus diseased plants are similar to those of X. campestris pv. vitians or X. campestris pv. dieffenbachiae from Xanthosoma or Syngonium. The authors felt that these xanthomonads strains are probably a distinct X. campestris pathovar or a unique variant which is metabolically similar to X. campestris pv. dieffenbachiae strains which do not hydrolyse starch. Further studies are needed to better characterize this pathogen. This is the first report of a bacterial disease on ornamental asparagus.
Sources
Norman, D.J.; Yuen, J.M.F.; Hodge, N.C. (1997) New disease on ornamental asparagus caused by Xanthomonas campestris in Florida.
Plant Disease, 81(8), 847-850.