How To Identify Bacterial Pith Necrosis And Control / Prevent Them On Tomato Plants?

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Quick Answer: How To Identify Bacterial Pith Necrosis And Control Them On Tomato Plants?

Pith necrosis of tomato plants is caused by different species of Pseudomonas and can be identified by wilting, yellowing of leaves, and lesions on the stems. Its likelihood can be controlled by planting in sunny, open areas with adequate spacing and air circulation. Avoid excessive nitrogen fertilization and discard the affected plants to prevent the spread of infection. There are no chemical sprays.

Are you wondering about identifying and controlling bacterial pith necrosis affecting tomato plants?

Then, check out this comprehensive guide prepared after extensive research to help you identify and control pith necrosis.

Scroll down for further information!

What Is Bacterial Pith Necrosis And How Does It Harms Tomato Plants?

Pith necrosis is caused primarily by the bacterium, Pseudomonas corrugated, which can affect fast-growing tomato plants. It can also attack the plants grown in greenhouses and high tunnels.

It affects the leaves and stems of tomato plants, causing lesions. It may rarely affect the fruits.

How To Confirm That Bacterial Pith Necrosis Is Troubling Your Tomato Plants?

Observe for the symptoms when the tomato fruits are at the mature green stage. The leaves of the affected plants appear yellow and wilting, which occurs in the upper portion of the plant. Pith has brown discoloration and necrosis, leading to hollow chambers.

The hollowing can lead to the cracking and breaking of tomato stems. The affected stems will have many adventitious roots all along.

The necrotic stems confirm the pith necrosis condition. Certain fruits may have greasy water-soaked brown tissue.

Check out this video on identifying tomato pith necrosis:

Natural Ways To Control Bacterial Pith Necrosis On Tomato Plants

There is no cure for severely affected tomato plants. But, if the infection is in the starting stage, the plants may recover after the spring when the weather becomes warm.

However, soil-inhabiting bacteria causing the condition may exist in the soil.

Method 1- Change The Crowing Conditions

The tomato plants at the initial stage of infection may recover as the weather becomes warmer and irrigation issues are corrected. The severely infected plants can not be recovered.

  • Water at the base of the plants– Plants may recover as the rapid growth during spring slows. Water only at the base of the plants using drip irrigation, soaker hoses, or by hand. Avoid overhead irrigation.
  • Correct excessive nitrogen in the soil– Follow the fertilization recommendation and correct nitrogen levels after the soil test.

Physical Ways To Control Bacterial Pith Necrosis On Tomato Plants

There are no effective physical ways to control bacterial pith necrosis on tomato plants. You may prune the infected parts of the plants before it spread to other parts and neighboring plants. 

If the plants are severely affected, destroy them. Also, sanitize the tools before and after pruning.

Chemical Ways To Control Bacterial Pith Necrosis On Tomato Plants

There is no effective chemical treatment or sprays for this disease. Copper fungicides may not work as the soil-borne pathogens causing this condition lives inside the plant. Also, there are no resistant varieties available for this condition.

How To Prevent Bacterial Pith Necrosis In Tomato Plants?

The best strategy to prevent bacterial pith necrosis is avoiding favorable conditions for the bacterium to survive.

You may reduce excessive nitrogen fertilization, ensure good air circulation, practice good sanitation techniques and follow crop rotation to prevent the incidence of the disease.

Method 1- Avoid The Use Of Excessive Nitrogen

Avoid using excessive nitrogen in the soil, especially when the nights are cool. You may do a soil test and follow balanced fertility programs.

Method 2- Reduce Humidity

Reduce humidity in the garden through the use of vents, especially on cloudy days. Also, follow proper plant spacing, staking, and pruning to provide adequate ventilation and reduce humidity.

Avoid working on plants when the foliage is wet.

Method 2- Practice Good Sanitation 

Remove infected plants, including roots, by bagging them to prevent the spread of infection. You may also burn the affected plant parts.

Clean pruning tools, stakes, ties, and trellises regularly using a commercial sanitizer or 10% household bleach.

Method 2- Practice Crop Rotation

Practice a three-year crop rotation in the vegetable garden. Grow plants resistant to Pseudomonas as these microbes reside in the soil until the following season.

What Causes Bacterial Pith Necrosis In Tomato Plants?

Bacterial pith necrosis is caused by soil-borne species of Pseudomonas affecting fast-growing tomato plants, primarily in greenhouses. It is favored by cool night temperatures, high humidity, plastic mulch, and high nitrogen levels in the soil. 

The prolonged periods of cloudy, cool weather also aggravates the condition. It can be brought in by workers’ hands, pruning tools, infected seeds, or transplants.

It can also survive in infected plant debris and soil.

Frequently Asked Questions

How to differentiate bacterial canker and pith necrosis?

Bacterial canker causes birds’ eye spots on the fruit. Pith necrosis rarely causes brown damaged areas on the fruits. The pith of stems with bacterial canker is white and spongy while the pith of stems with necrosis is hollow and dark brown.

Which plants are affected by pith necrosis?

Pith necrosis primarily affects tomato plants. It can also damage peppers and ornamental plants, including cranesbill geranium and chrysanthemum. It is favored by excessive irrigation, high humidity, low light, and high nitrogen in the soil.

Is tomato pith necrosis contagious?

Yes, tomato pith necrosis is contagious. The bacteria can spread from one infected plant to another by a variety of means, including infected seeds, plants, rainfall, splashing water, contaminated tools, and equipment during pruning.


I hope this guide has provided a few pointers for identifying bacterial pith necrosis and different measures to prevent it in tomato plants.

If you have any experience with this issue and have any tips or methods you would like to share, please do so in the comments section.

Lastly, I urge all readers to share this article with friends and family who may benefit from the information.