Recognizing and Combating Root Diseases

Last updated: 19.07.2024

Reading time: 4 minutes

Healthy roots are the basis for good development and growth of your crops. Damaged roots can promote diseases such as root rot or verticillium wilt and reduce your harvest. It is therefore important to act quickly if you suspect that your plants have diseased roots. In this article, we give you an overview of the most common root diseases in the garden.

This Article Contains:

How to Recognize Root Rot vs. Healthy Roots
Verticillium Wilt Fungus (v. Dahliae & v. Albo-Atrum)
Root Burn: Symtoms and Susceptible Plants

Quick Overview

Common Diseases at the Roots

Root Rot

Cause: Incorrect care (e.g. unfavorable water supply) or pathogens such as fungi (e.g. Phytophthora) and bacteria (e.g. Erwinia)
Symptoms: Rotten roots; chlorosis on leaves; plants are not stable in the soil
Risk of confusion with water deficiency

Verticillium Wilt Fungus

Cause: Fungus that infects plants via damaged roots
Symptoms: Chlorosis on leaves; individual shoots wilt; wrinkled bark
Risk of confusion with water deficiency

Root Blight

Cause: Fungi that occur in the soil (can also be introduced through purchased soil!)
Symptoms: Infested seedlings emerge poorly and fall over

How to Recognize Root Rot vs. Healthy Roots

Root rot can have various causes. In addition to fungi such as Phytophthora and bacteria, incorrect care can also be the cause of the symptoms. First rule out care errors before suspecting a plant disease! In our article on Recognizing and Combating Plant Diseases, you will find other possible causes and care errors that can also lead to root rot.
Possible biotic pathogens that cause root rot: Fungi such as Fusarium, Phytium, Phytophthora (these diseases are called hard rot, black rot or rotting disease) and bacteria such as Erwinia, Rhizomas or Pseudomonas attack plants; if care errors are the cause of damaged, rotten roots, these pathogens have a particularly easy time penetrating the plant; the exact cause of infestation is usually difficult to determine
Symptoms: Brown and rotten, sometimes muddy roots; this causes the plant to wilt (individual shoots gradually wither until the whole plant is wilted) and dies completely if the rot is severe; chlorosis on the leaves; plants are wobbly in the soil; possibly constrictions on the root neck or stem
Danger of confusion: The wilting of individual shoots is often interpreted as a lack of water, but can also indicate an infestation with root rot. Watering even more will only exacerbate the root rot. So before watering wilted parts of the plant, check whether the soil or roots are damp or rotten.
Our tip: Healthy roots are whitish to light brown and firm. Dark roots usually indicate root rot. Ferns are an exception: their roots are dark brown even without rot!
Susceptible plants: Seedlings (especially root rot and root burn); strawberries, potatoes, tomatoes (Phytophthora); however, the disease can affect almost any plant!
Recognizing and combating root rot (the article on this will follow soon!)

Spring onion roots. — Healthy roots are whitish to light brown, with the exception of ferns. Some diseases can cause roots to rot. Picture by Hans on Pixabay.

Verticillium Wilt Fungus (v. Dahliae & v. Albo-Atrum)

Symptoms: yellowed leaves and dried shoots (easy to confuse with drought damage and lack of water!) initially only individual shoots; bark becomes wrinkled
Like almost all root diseases, this fungus has a particularly easy time when the roots are already damaged (care errors due to unfavorable water supply?); the fungus penetrates the plant, inhibits water and nutrient uptake and the plants wither as a result
Susceptible plants: Over 200 host plants for this pathogen; woody plants such as maple, chestnut, lilac, rhododendron; needle trees are not affected; plants such as potatoes, peppers, tomatoes and strawberries are often affected
Recognizing and combating Verticillium fungus (article to follow soon!)

Keep Pests & Diseases at Bay!

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Root Burn: Symtoms and Susceptible Plants

Also known as emergence or fall sickness
Can be caused by various fungi in the soil
Symptoms: seedlings have problems emerging; seedlings show damage to roots, root neck and shoot; brown-black discoloration and constrictions; young plants fall over and die; individual plants that survive develop poorly with reduced (root) growth and usually wither in the end (June wilt)
Susceptible plants: Sugar beet, beetroot, spinach, chard and wild herbs such as white goosefoot, (soy) beans, peas, tomatoes, potatoes, barley, strawberries, etc.
Recognizing and combating fall sickness (the article on this will follow soon!)

Seedlings emerging. — This is what healthy seedlings look like. If they fall over as soon as they emerge, they could be infected with fall sickness! Image by onehundredseventyfive on Pixabay

Hopefully you have now found the cause of the symptoms of your diseased plants. As it is difficult to combat root diseases, you should use preventative plant protection. You can find tips on Preventive Plant Protection and measures in the article on this topic!

If you have any questions or comments, please write to us at [email protected].

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Cover picture by Alexey Hulsov on Pixabay

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