Common Tomato Diseases and Disorders
Tomatoes are the most popular garden vegetable crop in Texas. They are a good source of vitamin A and fair source of vitamin C. Fresh tomatoes are popular in salads, on sandwiches and sliced. They can be cooked and used in many ways.

As summer returns, so do the gardens but unfortunately some of the diseases and disorders of tomatoes return with them.

There are four disease and disorders we wanted to focus on.

Verticillium Wilt
Symptoms:
Vascular wilt disease that infects a plant through the roots. Initial symptoms include leaf wilting and yellowing. Vascular tissue appears brownish in cross section. Plants eventually collapse. Wilts tend to develop during the cooler periods of late spring. This wilt causes uniform yellowing and wilting of the lower leaves. As the disease progresses, younger leaves being to wilt and die, until only a few healthy leaves remain at the top of the plant. Although diseased plants are not killed, they are stunted and weak and produce small fruit. Verticillium wilt also causes discoloration of the vascular system almost identical to that in a Fusarium wilt.
Control:
Fungus survives in infected fields for several years. Long rotations (4 to 6 years), soil sterilization and soil solarization are the only effective controls. Utilize resistant varieties.
Fusarium Wilt
Symptoms:
Generally occurs in midsummer when air and soil temperatures are high. Diseased plants first develop a yellowing of the oldest leaves (those nearing the ground). Often affected leaves soon wilt and dry up. Serious problem in cucumber, watermelon and cantaloupe plantings but also affects many gardeners tomato plants. This disease may be expressed as damping off of young seedlings, or may be expressed as rapid wilting and vine decline of mature plants as they encounter stress. A yellow or brown discoloration may be noticed in the water conducting tissue when stem is cut in cross section. The stem remains firm and green on the outside, but exhibits a narrow band of brown discoloration in the vascular tissue. This discoloration can be viewed easily by slicing vertically through the stem near the soil line and looking for a narrow column of browning between the central pith region and the outer portion of the stem.

Control:
Long rotations (4 to 6 years). Race-specific resistance is widely available in commercial seed lines. Use disease resistant varieties. Fungus may survive in infected fields for many years and may be spread from field to field by farm equipment.
Blossom End Rot
Symptoms:
Blossom end rot is often misdiagnosed as a fruit disease. The blossom end of the fruit fails to develop normally, turning black-dark brown and eventually shriveling and becoming hard. Blossom end rot is usually due to a nutritional imbalance that is exaggerated by alternating periods of water stress.
Control:
Provide even soil moisture and follow recommended fertilization practices noting particularly the balance between nitrogen and calcium.
Tomato Cracking
Symptoms:
• Cracks appear in the stem end of tomatoes
• Two types of cracks appear in our area
– Radial cracks (spread outward from the stem scar) – occur when temperatures are
greater than 90° Fahrenheit and humidity is high
– Concentric cracks (circular cracks around the stem) occur from rapid fruit growth
stimulated by abundant wet weather or irrigation after a dry/drought period
• Black moldy growth can develop along cracks
• Cracks can easily be invaded by organisms that promote fruit rot
• Variations in soil moisture and temperature can cause cracking
• High nitrogen level combined with low potassium can also cause cracking

Control:
• Maintain regular irrigation and mulch to keep soil temperature and an adequate, consistent soil moisture level
• Maintain proper plant nutrition
• Plant resistant varieties
• Remove ripe fruit immediately after a rain to reduce cracking
• Plant at proper planting times for best temperature

For more information contact County Extension Agent Dale Dunlap at 806-826-5243
Article prepared by AgriLife Extension Summer Intern Kailey Hudson
The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by the Texas AgriLife Extensio