Abstract Phyllody and apostasis of cassava plants were frequently observed during recent disease surveys in the Cauca Valley of Colombia. Many valuable cassava clones have been affected rendering them unsuitable for hybridization. Light and electron microscopic observations have revealed the presence of mycoplasma‐like organisms in the diseased phloem tissues. The causal agent is sensitive to tetracycline and streptomycin at 1000 ppm a. i., but not to penicillin.
