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Tomato disorders

Quick facts

  • Tomato plants can develop disorders that distort plants and blemish fruits.
  • Tomato disorders are generally caused by varietal, environmental, or management issues
  • For most disorders, good nutrient management and watering practices will reduce occurrence of issues.
  • Different tomato varieties may be more or less likely to develop certain disorders.
  • You may have to try out different tomatoes before finding varieties that do well in your location. Seed catalogs often give information that can help you choose varieties that avoid problems.

Tomatoes are susceptible to many issues, some of which are caused by pathogens, some of which are caused by mismatches between tomato growth and the environment.  Below are some of the most common issues caused by plant nutrition and the Minnesota environment.

Blossom-end rot

Blossom-end rot is one of the most common tomato disorders seen in Minnesota.  It affects tomato fruit, especially the first set of fruit.

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Leaf roll

Leaf roll is a physical disorder of tomatoes associated with hot dry weather but it can occur in response to other stresses like fast growth and pruning. This disorder is believed to be a strategy to conserve moisture.

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Sunscald

Sunscald occurs on tomato fruit that have been exposed to too much sun. This is common in plants that have lost leaves from a leaf spot disease or insect feeding, but can also occur on plants that are over pruned or on fruit that are otherwise exposed to the sun.

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Growth cracks

Extremely fast fruit growth can cause growth cracks. This may be caused by periods of abundant rain and high temperatures or can happen when it rains or you water plants after a period of drought.

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Catfacing

Catface is a condition involving malformation and scarring of fruits, particularly at the blossom end.

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Yellow shoulders

Yellow shoulders refer to when the top area on tomato fruit (“shoulder”) never ripens, staying hard and yellow or green even as the rest of the fruit is red.  Tomatoes can also have issues ripening on the inside, with the inside flesh being white and hard.  No matter how long these tomatoes are left on the vine, the shoulder and interior do not ripen.

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Herbicide injury

The most common injury symptoms are caused by phenoxy herbicides such as 2,4-D (2,4-dichlorophenoxyacetic acid) and dicamba (substituted benzoic acid). These chemicals are growth regulators; they mimic plant hormones.

Tomato plants usually come in contact with the chemical through spray drift or the use of a sprayer that was previously used to apply an herbicide. It is also possible to expose tomato plants to broadleaf herbicides by using grass clippings from lawns recently treated for these weeds as mulch in the vegetable garden.

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Authors: Marissa Schuh, horticultural IPM Extension educator, Michelle Grabowski, Frank Pfleger and Sandy Gould

Reviewed by Natalie Hoidal, Extension educator

Reviewed in 2022

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