Association of phytoplasmas with a witches-broom disease of Withania somnifera (L.) Dunal in India

Abstract

A witches-broom disease of Withania somnifera first appeared in 1988 at CIMAP experimental fields, Lucknow, India. Thereafter, it spread to the commerical fields causing severe damage to the crop during the last 5 years. Phytoplasma was associated with the disease on the basis of symptomatology, mode of transmission, electron-microscopic studies and response of tetracycline spray on the recovery from diseased symptoms. Typical symptoms of the disease consisted of little leaf, shortening of internodes, excessive branching giving witches-broom appearance and premature drying and death of infected twigs and leaves. Ultrathin sections of infected leaf tissue showed pleomorphic bodies (measuring 250–550 nm) in sieve tubes of phloem. Disease was transmitted from infected plants to healthy plants through grafting. The treatment of infected plants with tetracycline provided temporary recovery from the infection.