The Most Common Diseases That Affect Gardens

Garden Diseases

Mold, fungus, and viruses can affect any plant and destroy a garden if not properly dealt with in a timely matter.

A plant disease’s symptoms can vary based on its cause, but these can include leaf spots, fruit rot, wilting, root rot, and unusual or stunted growth.

Fungi are the main culprits of plant disease and are responsible for most of the problems that you may experience in your garden.

They can devastate a garden if not properly dealt with and in a timely matter. Fungi can overwinter in soil and plant debris.

Viruses, on the other hand, can be completely disastrous because there is no treatment, therefore the infected plant needs to be removed and disposed of properly to prevent further spread.


Molds are a type of fungus that spreads by releasing spores into the air and it grows multi-cellular filaments that are known as hyphae.

Molds digest organic material and it changes the soil’s chemical makeup, improving the soil over time.

Some molds will not affect a plant while others can cause a reduction in vegetation, but not doing anything can be harmful to your health if inhaled.


  • Essential oils – neem, mint, cinnamon, and rosemary oils are antifungal. You can use a mix of the oils or a single oil and add 3 tablespoons of oil into a spray bottle, add water, and shake the bottle vigorously before spraying.
  • Baking soda – neutralizes the ph levels on the surface of the leaf, killing the mildew. Add 3 tablespoons to one gallon of water, or 1 teaspoon to the essential oil spray.
  • Cinnamon – powdered cinnamon can be sprinkled on the soil and leaves as well as used for a preventative measure.
  • Remove any parts of the affected plant and throw them away and never put them in a compost pile.


Powdery mildew is a fungal disease that can cripple plants and produce unsightly damage but it isn’t deadly to plants.

Powdery mildew is a generic term used to describe fungi that cause a fuzzy powder look on leaves.

The best environment for this fungal disease is shady areas that have inadequate air circulation, high humidity, and mild air temperature.


When a plant is infested, it looks as if someone sprinkled baby powder on the leaves, some leaves will turn a red to purple color, and young leaves may become twisted and deformed when they grow.


Like powdery mildew, downy mildew is a generic term for a variety of plant diseases and when you see the signs of mold, it will be too late for the plants.

All that can be done is prevention and this can be done naturally.


Yellow spots on the surface of the leaves that are between the veins. The spots get bigger and take over the area between the veins.

The veins will then turn brown and the leaf will die. If enough leaves are affected then photosynthesizing can’t happen and the plant will die.


Fungi break down organic matter and decompose them which is good for the soil but they can kill a plant by killing its cells in order to feed on the nutrients in it.

While some fungi are good for the soil and eatable, some are destructive for plants like blight which is a fungal disease.


  • Apple cider vinegar – 1 tablespoon per 1 gallon of water, shake well before using, ad spray the affected area.
  • Essential oils – peppermint, cinnamon, and thyme.
  • Cinnamon – powdered cinnamon can be sprinkled on the soil and leaves as well as used as a preventative measure.
  • Baking soda – 1 tablespoon per 1 gallon of water, mix the solution well, and spray on the affected area.


Rhizoctonia Aerial also known as web blight is characterized by small water-soaked spots that spread throughout the plant’s leaves.

To know for sure if you are dealing with Rhizoctonia aerial for a fungus, a lab test needs to be done to pinpoint the issue.


Symptoms start with leaf spots on the leaves and can get more severe within a week.

Leaf spots are brown, irregularly shaped spots that can also form on the stem of the leaf.

Rhizoctonia aerial creates root rot, where the roots turn brown and are mushy.


Rhizoctonia solani is a soil-borne pathogenic fungus, also known as damping off, and it can cause serious losses in the harvest.

To know for sure if you are dealing with Rhizoctonia solani for a fungus, a lab test needs to be done to pinpoint the issue.


Rhizoctonia solani lives in the top part of the soil where it affects the stem of the plant near the surface of the soil.

The stem will turn brown to a reddish-brown color because of lesions that form and get bigger.

The stem of the plant will also look dry and wilted because the fungus restricts the flow of water and the nutrients that the plant needs at the roots.

Rhizoctonia solani also causes the roots to turn brown and mushy because of root rot.


Damping off is a fungal disease that comes from the soil and mainly affects seedlings, leading to the stem rotting as well as root issues at the surface of the soil and below.

This can happen when old seeds are sown in soil that is cold and wet as well as high humidity levels.


Shortly after breaking the surface of the soil, seedlings collapse and fall over because the stem of the seedling has rotted along with the roots.


Fusarium wilt prefers warmer weather with highly acidic soil and affects a plant through wounds to the roots that are caused by feeding nematodes.

This fungus is known to be able to live in the soil for years, is spread by water, and prefers dry hot weather where it can become damaging above 80 degrees.


Typically, the symptoms of the disease show later in the growing season and appear in the lower leaves.

As the disease progress, it moves up the plant causing the foliage to wilt and become yellow.

Seedlings will have stunted growth, turn yellow, and die while older plants will experience stunted growth and turn yellow.

The leaves of an infected plant will wilt, sag, turn yellow, and dry out.


Cercospora leaf spot is part of the Cercospora genus which includes more than 1,200 different fungal species.

This fungal disease prefers air temperatures above 80 degrees with high humidity and is known to be an issue under irrigation systems.


Cercospora leaf spot causes brown circular spots on the lower leaves in late June to July, they will turn yellow, orange, or red along with the spots, the border of the leaves will be dark brown to a reddish-purple color, and they will fall off soon after.


Leaf spot is a bacterial or fungal issue that is caused by bacteria or fungi spreading spores or some insects.

it is a broad description given of many different diseases that affect the foliage of many different plants, shrubs, and trees.

Leaf spot prefers high humidity for a long period of time and typically first affects a plant around the lower branches where the humidity will be elevated along with shade.


Leaf spot causes spots on older leaves that are water soaked with the spots being between the veins of the leaves and they are angular in shape.

The spots turn black and if there are enough spots then the leave will die.


Plant viruses can cause devastating damage to a garden with 73 genera and 49 families that are currently known because of the cultivation of plants and it is unknown how many are in the wild.

Currently, there is no treatment for plant viruses, the only option is their prevention and the removal and proper disposal of affected plants.

To properly dispose of an affected it is recommended to throw it away with your trash or burn them are the best option.


Yellow dwarf is a virus that is spread by aphids and is also known as barley yellow dwarf and cereal yellow dwarf.

Yellow dwarf affects all grasses, therefore when treating or when preventing aphids, remember to treat all plants around the home as well as the lawn.


This plant virus causes the leaves of the plant to turn yellow starting at the tips of the leaf and moving to the base of the leaf, turning the whole leaf a golden yellow color, and stunted growth is another main symptom of this virus.


The cucumber mosaic virus has the most worldwide distribution and it is from plant to plant through the sap of the plant or through aphids.

Plants in the cucumber family are most affected by this virus but it also affects more than 100 plant families and over 1,200 plant species.


Cucumber mosaic stunts the plant’s growth, the leaves form dark green and light green mosaic patterns, miss-shaped leaves, yellow streaks in the leaves, yellow spots on the leaves, and lines or spots in the shape of rings on the leaves or the fruit.


The tobacco mosaic virus is the first virus discovered in 1886 but it wasn’t until 1930 that it was understood to be a virus.

This virus has the ability to affect over 350 different plant species and it can cause a lot of devastation in any kind of garden.


Tobacco mosaic can cause spots or smears of color, cells in the plant will die, the growth will be stunted, the leaves will become curled, and the plant will turn yellow.

Joel Simon

As a kid, Joel found enjoyment in caring for the many houseplants he grew up with, learning how to transplant them safely, cloning them, and more. At about the age of 10, he wanted to see if he could sprout an orange seed from a store-bought orange and ended up using it as a science experiment in a school project. Throughout the many years of gardening, he has helped many friends and family set up their food and botanical gardens. After years of caring for plants, he was talking with other gardeners and discovering old methods of farming and botanical gardening. Joel has decided to share his knowledge for others to enjoy as he has for many years.

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