LATENT INFECTIONS OF IN-VITRO ANTHURIUM CAUSED BY XANTHOMONAS-CAMPESTRIS PV DIEFFENBACHIAE

Latent infections of tissue-cultured Anthurium andraeanum Lind. caused by the blight pathogen, Xanthomonas campestris pv. dieffenbachiae (Mc Culloch & Pirone) Dye, were examined. The pathogen survived in or on c allus for over 4 months without producing symptoms in callus or turbid ity in the medium. The pathogen survived for more than 1 year on or wi thin stage II shoots without producing symptoms and was successively t ransferred three times as latently infected shoots were multiplied. Th e pathogen did not grow or survive for more than 2 weeks in Murashige and Skoog medium lacking plant material. The addition of coconut water enhanced bacterial growth and produced turbidity in culture media. La tently infected in vitro anthuriums may be inoculum sources for subseq uent outbreaks of the disease.