Tomato mosaic virus

Affected plants show light and dark green mottling and distortion of the youngest leaves. The latter may be stunted or elongated resembling fern leaves. Under high temperature and light intensity, mottling can be severe. Under low temperature and low light intensity, stunting and leaf distortion are severe. Internal browning of the fruit sometimes occurs; this symptom is most common when fruits become infected at mature green or pink stage.

The disease can be seed-borne but can also survive on plant debris in the soil and so re-infect newly planted crops. The virus is easily mechanically transmissible by contact between plants or through human activities (transplanting seedlings or pruning).