Cause Tomato big bud has been reported in California and other regions. It is caused by a phytoplasma that is spread by leafhoppers, and the specific phytoplasma involved depends on the region. In California, the disease is caused by the beet leafhopper-transmitted virescence agent. The disease is rare on tomato but also occurs on celery, radish, and Chinese cabbage. The phytoplasma overwinters on weeds or other crop hosts. The disease follows the leafhopper migration.
Symptoms A range of symptoms can develop, depending on the phytoplasma involved. In California, lateral shoots exhibit leaf or shoot proliferation and greening of flower petals. In other cases, leaves may be small, distorted, and chlorotic. Aerial roots may appear and leaf veins may appear purple in color. Normal fruit may fail to develop.
- Control weed hosts.
- Control leafhopper vectors.
Chemical control This disease is rarely a problem in the PNW but management of leafhoppers may be warranted under certain conditions. See the PNW Insect Management Handbook for details.