The symptoms expressed by infected tomato plants vary depending on the type of TCDVd strain, tomato variety, age of the plant, plant vigour and climatic conditions. Initial symptoms appear as reduced growth and yellowing of leaves (chlorosis) in the young terminal parts of the plant, 3-6 weeks after initial infection. With time, the infected plants may become stunted, chlorosis may become more pronounced or turn to bronzing and/ or purpling; leaves may show necrotic lesions and become brittle and distorted.The commonly observed symptoms are stunting, overall bunchiness, reduced leaves and fruit, leaf chlorosis, leaf and petiolar necrosis, downward bending of leaves, fruit distortion and even death of plants.
All pospiviroids, including TCDVd, can easily be transmitted mechanically and spread by contact with contaminated pruning tools, farm equipment, clothing, crop handing, and contact between neighboring plants. Depending on the type of viroid and host plant, viroids can also be transmitted by seeds, vegetative propagation, pollen, grafting and insects. Although transmission of TCDVd by seeds is strongly suspected, TCDVd was not detected in seeds obtained from TCDVd-infected tomato plants.
