Cause Possibly high temperatures or exposure to sun. Chlorophyll breaks down more slowly in certain areas of an affected fruit than the fruit areas turning red.
Cause The tomato yellow leaf curl virus was found in California during 2007 and is transmitted by adult silverleaf whiteflies, but not by seed. This viral disease has not been reported in the Pacific Northwest.
Symptoms The margins of tomato leaves turn yellow and a yellow mottling of the leaf area. Leaves cup upwards, may be reduced in size, and flowers may drop.
Greenhouse Plants, Tomato - Common Mosaic of Tomato (Internal Browning of Fruit)
Tomato plant exhibiting symptoms of TMV.
Image by OSU Plant Clinic, 2013.
Image by OSU Plant Clinic, 2013.
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.
We assume the plant on the left is infected.
OSU Extension Plant Pathology Slide Collection, 19
Cause The fungi, Leveillula taurica (syn. = Oidiopsis taurica, Erysiphe taurica) and Oidium neolycopersici (syn. = Pseudoidium neolycopersici), are both occurring on tomato in western Oregon. Oidium lycopersici has been reported on tomato in California.
Powdery mildew colonies can occur on fruit stems as well as leaves.
Jay W. Pscheidt, 2020.
Some powdery mildew fungi can produce profuse white powdery growth on the upper leaf surface as seen here while others may only be seen as a sparse growth on the leaf's lower side.
Jay W. Pscheidt, 2020.
Powdery mildew colonies on the underside of a tomato leaflet.
Photo by Cynthia M. Ocamb, 2020.
A tomato plant with a large number of discrete powdery mildew colonies on the leaves.
Photo by Cynthia M. Ocamb, 2019.
Powdery mildew colonizing extensively the stems, petioles, and leaflets of an affected plant. Note the whitish cast on the stems and petioles.
Photo by Cynthia M. Ocamb, 2016.
Powdery mildew heavily colonizing on a tomato plant and causing the affected leaflets to turn brown and die.
Photo by Cynthia M. Ocamb, 2016.
See:
Tomato Varietal Resistance
Cause Meloidogyne hapla, a sedentary endoparasite. Only second-stage juveniles (the infective stage) and adult males (which may be rare) are in soil. Root-knot nematodes are found nearly everywhere and are the only known nematode pest of Oregon vegetables grown in the greenhouse. The nematodes usually are introduced with infested soil or mulch materials and in transplants.
Galls on roots are due to nematode and not bacteria.
Herald Jensen.
Note the numerous galls or knots along the roots.
Photo by R. H. Henderson, 1976.
Lots of tomato roots knotted up with a lawn background.
Cause Botrytis cinerea, a fungus. Symptoms of ghost spot on fruit result from the fungus' unsuccessful attempt to infect. There is no rot, but fruit is unmarketable. The fungus can also colonize leaves and stems. The disease is promoted by wet, humid conditions.
Faint, pale halos appear white on immature fruit, yellow on ripe fruit.
OSU Extension Plant Pathology slide
A tomato with Botrytis (cause of gray mold) infecting the stem.
