How To Identify Walnut Wilt And Control / Prevent Them On Tomato Plants?

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Quick Answer: How To Identify Walnut Wilt And Control Them On Tomato Plants?

Walnut wilt will cause wilting of tomato plants due to the uptake of juglone chemicals and eventually kill them. There is no cure for a plant affected by walnut toxicity. Transplant the tomato plants away from the walnut trees. Also, growing the plants in a raised bed by incorporating large amounts of organic matter and improving drainage can diminish the effects of juglone.

This is a complete guide to help you identify walnut wilt and control / prevent them on tomato plants.

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What Is Walnut Wilt And How Does It Harms Tomato Plants?

Walnut wilt is a disorder that occurs due to the uptake of a chemical called juglone which is toxic to tomato plants.

 It occurs if a tomato planted is planted in the vicinity of walnut trees. When the tomato plants develop walnut wilt, they wilt and die quickly.

Here is a useful experiment on walnut wilt:

How To Confirm That Walnut Wilt Is Troubling Your Tomato Plants?

You may look for telltale signs if the tomato plants are near walnut trees. It may cause wilting, drooping, or curled leaves that become severe over time. It will have discolored stems with a dark color or leaves with a yellowish shade.

There may be stunted or slow growth. Within a few days, the plant may wilt and die. It usually happens between early to mid-summer.

Check out this video to identify walnut wilt:

Natural Ways To Control Walnut Wilt On Tomato Plants

There is no cure to control walnut wilt on tomato plants. Once wilting occurs, the effect can not be reversed and can’t save the plants. You may remove and destroy dead plants.

Method 1- Change The Crowing Conditions

The high level of organic matter around the tomato plants may help reduce the condition. It provides beneficial bacteria that may degrade harmful chemicals. Also, excellent drainage will help in reducing the toxicity of juglone.

  • Incorporate rich organic matter– Add rich organic matter, rotted manure, composted grass clippings, and cover crops in the soil around the tomato plants. The high level of organic matter will provide beneficial microbes that can break juglone.
  • Provide adequate drainage– Provide good drainage with new soil to minimize the damage.

Physical Ways To Control Walnut Wilt On Tomato Plants

The most effective way to control walnut wilt is to transplant them to a newer location or raised bed away from walnut trees.

Method 1- Transplant The Tomato Plants

Transplanting the tomato plants from the juglone-affected area is the only feasible solution to save the plants from walnut wilt.

  • Transplant the tomato plants– Remove the tomato plants from the affected area. Transplant them into fresh containers with sterile potting mix.
  • Move away from walnut trees– Move the plants at least 50 feet away from walnut trees. You may plant them in a raised bed lined with landscape fabric.

Chemical Ways To Control Walnut Wilt On Tomato Plants

There are no chemicals to treat walnut wilt on tomato plants. Juglone can stay in the soil for a long time and can not be easily neutralized. The decomposition of juglone can be accelerated by well-drained and aerated soil with a healthy microbial population.

How To Prevent Walnut Wilt In Tomato Plants?

There is no cure for walnut wilting and juglone poisoning. The best preventive measure is to avoid planting tomatoes near walnut trees. 

Take care to remove debris from the walnut tree and grow tomatoes in a raised bed.

Method 1- Avoid Planting Near Walnut Tree

Avoid planting tomato plants near the spread of a walnut tree root system. It should be planted at least 50-80 feet away. Also, avoid planting tomatoes for at least two years in locations where walnut trees have been grown before as juglone can remain in the soil for several years.

Method 2- Clean Debris Of Walnut Tree

Clean up the debris, including fallen leaves, nuts, and other black walnut tree debris, regularly. Also, avoid using them as compost for tomato plants as they may still contain harmful chemicals.

Method 3- Grow In Raised Bed

Underline the garden with the plastic or weed barrier before planting tomatoes in a raised bed. It will prevent the walnut tree roots from growing into the raised beds and affecting the plants.

Also, build raised beds with wood, stone, or concrete barriers to limit root growth.

Check out this video for preventive measures to avois walnut wilt:

What Causes Walnut Wilt In Tomato Plants?

Walnut wilt can be caused by the leaching of juglone chemicals from the walnut trees into the soil during rain or released from roots.

It is uptaken by the tomato roots that make contact with the roots of the walnut or the soil, causing wilting of the plants.

Frequently Asked Questions

What are the sources of juglone?

Juglone can be produced by different parts of the walnut tree. The primary source is from the roots of the tree but can also be found in the bark, leaves, and hulls of the walnut. It can be spread into the soil.

Which plants are susceptible to walnut wilt?

The different plants susceptible to walnut wilt are tomato, potato, blackberry, apple, lilac, asparagus, chrysanthemum, and peony. These plants react to chemicals from walnut trees and will die. It is recommended to avoid planting these plants near black walnut trees.

Can you save wilted tomato plants?

The tomato plant can be wilted due to underwatering, overwatering, and transplanting shock.If these issues are identified early, you may revive a wilted plant. However, tomato wilting due to walnut juglone or pathogens can not be revived.


Hopefully, this guide has helped you understand walnut wilt on tomato plants and methods to control and prevent them.

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