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7 Hosta Diseases (Signs with Images And Treatment)

The hosta is an incredibly beautiful ornamental plant. Adding a succulent touch to any garden plot is as simple as planting one of these plants. 

Diseases rarely affect Hosta, but leaf-eating pests and insects can pose a threat to its health. 

The first signs of visible damage should be interpreted as a call to action. 

It’s critical to treat hosta diseases as soon as they appear, as waiting too long to address a problem could result in the plant dying.

What I’m about to share with you is details on common hosta diseases and how you can treat them. 

I’ll also share some real-life pictures of diseases pests that the plant is known to affect.

And how to avoid your hostas’ downfall by dealing with them.

You can easily tell by the outward signs that the first signs of disease are developing on your plant. 

So, what are the most common diseases that affect the hosta? 

[1] Hosta Virus X (HVX)

Late in the twentieth century, American scientist Lockhart discovered Hosta Virus X (HVX). 

The disease is spread by sap that gets on garden tools or hands while pruning or dividing shrubs. 

When you use an unwashed hoe or your hands to touch healthy plants, the virus enters the plant’s tissue through the cuts and wounds and begins to feed and multiply.

Signs 

Dark green stripes on veins of leaf confirm hosta virus x
Dark green stripes on veins of leaf confirm hosta virus x (Source)

Prior to the discovery of the virus, yellow spots, small flecks, dashes, and rings were mistaken for unusual hosta coloration. 

However, it was later discovered that it is a disease that causes stunted growth and curling leaves.

Hosta Virus X (HVX) distinguishing characteristics:

  • The heterogeneous coloration of the leaf due to variations in tissue density and coloration;
  • Dark green stripes on veins of leaf confirm hosta virus x infection. 
  • Chlorosis occurs, and as a result, the foliage turns a pale shade of green. Sometimes the vein starts turning yellow in an advanced stage. 
  • Small, fuzzy spots that look like a mosaic
  • stunted growth of the plant, resulting in dwarfism;
  • The flowers’ color is faded, and there is no ovary to be found.

Immediate action: If an infestation is detected, the entire garden should be replanted as far away from the infected area as possible, and the affected plants should be disposed of as household waste or burned to prevent the hosta virus from spreading to other plants.

Even though Hosta sieboldiana, also known as Siebold’s plantain lily, and its hybrids are virus-resistant, that doesn’t mean they’re completely free of the risk of infection.

Treatment

There’s no point in trying to save the plant if a virus has been found because the disease is incurable. 

It infects every part of the hosta plant, eventually killing it. I recommend burning the diseased hosta and disinfecting the used tools.

[2] Phyllosticta Leaf Spot

Indoor and outdoor plants are both susceptible to Phyllosticta Leaf Spot also known as brown spot disease. 

High humidity and temperatures above 77°F (25°C) are ideal for the Phyllosticta fungus.

Signs

 Phyllosticta Leaf Spot of Hosta
Phyllosticta Leaf Spot of Hosta
  • Large brown spots appear on the surface of plant leaves;
  • The spots gradually blend together to form a large lesion area.
  • The fungus appears as a white or yellowish plaque on the surface of the spots;
  • The disease frequently affects both the leaves and the flower stems of hostas;
  • Infected plants gradually dry out and die.
  • Brown spots appear on the leaves, which then crack and fall apart.
  • The advanced stage of the Phyllosticta leaf spot leads to the death of the plant. 

Treatment

Reduce the frequency and volume of watering of the hosta by burning leaves and stems with fungal spore centers. 

You should discard the entire plant if it is severely damaged. 

You should remove the diseased hostas from their original locations to prevent them from infecting other plants in the area.

Copper-based fungicides are effective in combating the disease. Spraying every 10 days until flowering begins is the treatment for brown spot disease. 

[3] Gray Rot

Gray rot fungi are omnivores, as are their hosts. Herbaceous plants, flowers, and fruit and berry plants are all affected. 

In addition to being widespread, the disease can be deadly for your hosta. 

The plant will die if you do not take appropriate measures in a timely manner. 

The botrytis fungus grows mycelium on the plant and releases spores that are carried by the wind to other nearby plants.

Signs

Dried leaf Edges and Tips Due to Gray Rot
Dried leaf Edges and Tips Due to Gray Rot

Gray rot symptoms differ depending on the stage of the disease’s development.

  • Botrytis spores are visible in the early stages of infection as blotchy, deformed, and dried leaf edges and tips.
  • The disease’s early stages begin with the decay of the hosta’s leaf tips.
  • Advanced stage: the rot has spread to every part of the leaf.
  • Initially, treatment consists of spraying fungicides on the diseased leaves.
  • You need to destroy the affected plant if the infestation is severe.

Treatment

Preventing gray rot is much easier than treating it once it has occurred. 

Early in the spring, when the soil is still loose, apply the first soil treatment.

Spray copper-based contact fungicide on planting sites using a sprayer.

[4] Root, Stem and Collar Rot

It’s a fungal rot caused by phytophthora. It’s a fungus that lives in the soil and attacks plants by infecting the roots and rhizome. 

These fungi can remain inactive in cold weather and activate when the environment becomes warmer and more humid.

It causes rot at a much slower rate than bacterial soft rot. This time, the odds are in your favor to save the pieces.

Signs

Signs of Hosta Root Rot
Signs of Hosta Root Rot

It is nearly impossible to predict root rot at the early stages without first identifying and inspecting the root system. The roots will rot, causing some symptoms to appear above ground.

The discoloration of the leaves is a surefire way to spot root rot. 

The leaves turn yellow from the edges to the center first, then discolor and dry out before falling off. 

Treatment

There is no such thing as a treatment for this condition whatsoever. 

Do not use soil from beneath the plant, and do not transplant infected shrubs or those suspected of being infected. 

To prevent the fungus from spreading further, remove all diseased hostas from the garden and dispose of them properly.

  • Treatment of the early stages of the disease entails digging up your hosta and Removing any soft roots and any rhizome material that isn’t hard and white, like coconut meat.
  •  Once clean, use hydrogen peroxide on it a couple times then let it dry thoroughly in the sun.
  • Use a systemic fungicide like Liquid Copper Fungicide to treat the problem. Phyton could also be a good option. 
  • Now, I’d dig out the soil in that hole and replace it.
  • If the infestation is too severe to be treated, dispose of the entire plant and the surrounding soil to prevent it from spreading further.

Copper Sulfate And Bordeaux Liquid Spraying Are Effective

However, putting the plant’s health at risk is not a good idea. As soon as the first leaf turns yellow, dug up the hosta thoroughly examined for any signs of root rot. 

Cut the affected areas with a sharp knife, and treat the cuts with fungicides or crushed activated charcoal. 

Do not replant the diseased hosta until it has dried out for 1-2 hours and then plant it in a new container.

[5] Bacterial Soft Rot

Bacterial soft rot can be caused by a variety of bacteria and typically occurs when a leaf has been damaged. 

Winter icing can also leave these types of wounds. It usually appears during the warming period after a frost.

Signs

Decaying Hosta Roots Due to Bacterial Soft Rot
Decaying Hosta Roots Due to Bacterial Soft Rot

The decaying cuttings and lower leaves give off a distinct rotten smell that you won’t be able to mistake for anything else. 

You will see some visible damage to the plant. This explains why the hosta’s leaves have developed new brown spots.

Treatment

Plants that are infested should be removed and destroyed. 

Make sure all tools that have come into contact with the plant are thoroughly cleaned and wash your hands and gloves thoroughly as well.

Due to the fact that the bacteria spreads slowly and only to the damaged areas, removing the entire garden isn’t necessary for this situation.

[6] Anthracnose

The disease affects healthy leaves and neighboring shoots quickly, and it is very widespread. 

The most vulnerable plant species are those that require a lot of shade and a lot of moisture.

Signs

Round Shaped Brown Spots are Sure Sign of Anthracnose
Round Shaped Brown Spots are Sure Sign of Anthracnose

When a hosta is infected, you’ll notice small round shaped brown spots on the leaves that grow larger and have darker borders, much like rust on the plant. 

The spots literally “tear” the leaf, leaving only the tough veins intact.

Treatment

Get rid of diseased leaves, lower humidity levels, and make sure plants have adequate ventilation (make sure there is plenty of room for air circulation).

Then, use a fungicide to keep the remaining healthy leaves from becoming infected again.

[7] Crown rot (Southern Blight)

Petiole rot, also known as crown rot, is a dangerous fungal disease.

Petiole rot, also known as crown rot, is a dangerous fungal disease. It is caused by a fungus called fusarium, which rots the roots from within. 

It isn’t usually a big deal until it gets into the crown, at which point you have to cut it out until you get to clean tissue. 

Fusarium can be a bigger problem in potting soil that dries out too much between waterings, but it usually has to get on the plant or soil somehow for it to become a major issue.

Signs

Hosta Become Floppy Spongy and Rotten at the Base
Hosta Become Floppy Spongy and Rotten at the Base Due to Crown Rot

Yellowing and wilting of the leaves along the outline are the primary symptoms. 

At the base of the leaf, it becomes floppy, spongy and  rotten.

Leaves that are too large to support themselves can “fall off” the main shrub altogether. 

You may also visually identify fungal filaments (mycelium) that are white. 

As the fungus grows, it spreads tiny round sclerotia seeds, which eventually cover the whole plant. 

When it’s cold outside, the fungus is dormant, but when it gets warmer and wetter, it comes to life.

Hosta Base Rotten Duew to Crown Rot
Hosta Base Rotten Duew to Crown Rot

Treatment

There is no treatment for this disease. Avoid using the old soil for replanting.  

To stop the spread of the fungus, get rid of or destroy any infected hosts in the garden.

Now, you should now be able to identify and treat common hosta diseases. If you have any questions or suggestions, please share them with me.